Vox: All Posts by Brad Plumerhttps://cdn.vox-cdn.com/community_logos/52517/voxv.png2018-12-28T14:50:15-05:00https://www.vox.com/authors/brad-plumer/rss2018-12-28T14:50:15-05:002018-12-28T14:50:15-05:009 questions about climate change you were too embarrassed to ask
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<img alt="earth" src="https://cdn.vox-cdn.com/thumbor/NHaNizZL5z6na1KL5U2EI3i1H30=/0x255:2040x1785/1310x983/cdn.vox-cdn.com/uploads/chorus_image/image/55048473/North_America_from_low_orbiting_satellite_Suomi_NPP.0.jpg" />
<figcaption>Our choices do matter. | NASA/NOAA/GSFC/Suomi NPP/VIIRS/Norman Kuring</figcaption>
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<p>Basic answers to basic questions about global warming and the future climate.</p> <p id="yCVFyG"><em>This explainer was updated by Umair Irfan in December 2018 and draws heavily from a </em><a href="https://www.vox.com/cards/global-warming"><em>card stack</em></a><em> written by Brad Plumer in 2015. Brian Resnick contributed the section on the Paris climate accord in 2017.</em></p>
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<p id="wfA9Bo">There’s a vast and growing gap between the urgency to fight climate change and the policies needed to combat it. </p>
<p id="AI6S43">In 2018, the United Nations’ <a href="https://www.vox.com/2018/10/8/17948832/climate-change-global-warming-un-ipcc-report">Intergovernmental Panel on Climate Change</a> found that it is possible to limit global warming to 1.5 degrees Celsius this century, but the world may have as little as 12 years left to act. The US government’s <a href="https://www.vox.com/2018/11/24/18109883/climate-report-2018-national-assessment">National Climate Assessment</a>, with input from NASA, the Environmental Protection Agency, and the Pentagon, also reported that the consequences of climate change are already here, ranging from nuisance flooding to the spread of mosquito-borne viruses into what were once colder climates. Left unchecked, warming will cost the US economy hundreds of billions of dollars.</p>
<p id="pJOT9O">However, these facts have failed to register with the Trump administration, which is actively pushing policies that will increase the emissions of heat-trapping gases. </p>
<p id="WLYoet">Ever since he took office, President Donald Trump has rejected or undermined President Barack Obama’s signature climate achievements: the Paris climate agreement; the <a href="https://www.vox.com/energy-and-environment/2017/10/10/16443246/gop-climate-health-care">Clean Power Plan</a>, the main domestic policy for limiting greenhouse gas emissions; and <a href="https://www.vox.com/2018/4/2/17181476/epa-fuel-economy-standards-tesla">fuel economy standards</a>, which target transportation, the largest US source of greenhouse gases.</p>
<p id="MCgd69">At the same time, the Trump administration has aggressively boosted fossil fuels: opening unprecedented swaths of public lands to <a href="https://www.vox.com/policy-and-politics/2018/3/5/16853432/ryan-zinke-interior-department-secretary">mining and drilling</a>, attempting to bail out foundering <a href="https://www.vox.com/energy-and-environment/2018/1/9/16866196/perry-coal-bailout-nopr-ferc">coal power plants</a>, and promoting hydrocarbon exploitation at <a href="https://www.vox.com/energy-and-environment/2018/12/14/18139402/cop24-climate-change-katowice-poland">climate change conferences</a>.</p>
<p id="1DxEUk">Trump has also appointed <a href="https://www.politico.com/story/2018/03/07/trump-climate-change-deniers-443533">climate change skeptics</a> to key positions. Quietly, officials at these and other science agencies have been removing the words “climate change” from <a href="https://www.vox.com/2017/12/20/16793010/cdc-word-ban-trump-censorship-language">government websites</a> and press releases. </p>
<p id="W02Fjj">Yet the evidence for humanity’s role in changing the climate continues to mount, and its consequences are increasingly difficult to ignore. Atmospheric carbon dioxide concentrations now top 408 parts per million, a threshold the planet hasn’t seen in <a href="http://www.climatecentral.org/news/we-just-breached-the-410-parts-per-million-threshold-21372">millions of years</a>. <a href="https://www.vox.com/energy-and-environment/2018/12/14/18139402/cop24-climate-change-katowice-poland">Greenhouse gas emissions</a> reached a record high in 2018. <a href="https://www.vox.com/2018/12/27/18150160/natural-disasters-2018-hurricanes-wildfires-heat-climate-change-cost-deaths">Disasters</a> worsened by climate change have taken hundreds of lives, destroyed thousands of homes, and cost billions of dollars. </p>
<p id="j4r1zX">The big questions now are how these ongoing changes in the climate will reverberate throughout the rest of the world, and what we should do about them. The answers bridge decades of research across geology, economics, and social science, which have been confounded by uncertainty and obscured by jargon. That’s why it can be a bit daunting to join the discussion for the first time, or to revisit the conversation after a hiatus. </p>
<p id="LoGNhO">To help, we’ve provided answers to some fundamental questions about climate change you may have been afraid to ask. </p>
<h3 id="2MKSZ7">1) What is global warming?</h3>
<p id="4X50Fv">In short: The world is getting hotter, and humans are responsible.</p>
<p id="xwtrxV">Yes, the planet’s temperature has changed before, but it’s the rise in average temperature of the Earth's climate system since the late 19th century, the dawn of the Industrial Revolution, that’s important here. Temperatures over land and ocean <a href="https://climate.nasa.gov/vital-signs/global-temperature/">have gone up</a> 0.8° to 1° Celsius (1.4° to 1.8° Fahrenheit), on average, in that span:</p>
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<img alt=" " data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/40NEq6iy66zMUVZUXB-MeVMn90Y=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/10346257/Screen_Shot_2018_03_05_at_10.29.11_AM.png">
<cite><a href="https://earthobservatory.nasa.gov/Features/WorldOfChange/decadaltemp.php">NASA Earth Observatory</a></cite>
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<p id="xUXxBB">Many people use the term “climate change” to describe this rise in temperatures and the associated effects on the Earth's climate.<strong> </strong>(The shift from the term “global warming” to “climate change” was also part of a deliberate <a href="https://www.motherjones.com/files/LuntzResearch_environment.pdf">messaging effort</a> by a Republican pollster to undermine support for environmental regulations.)</p>
<p id="503VcF">Like detectives solving a murder, climate scientists have found <a href="https://www.vox.com/cards/global-warming/how-do-we-know-humans-are-responsible-for-global-warming">humanity’s fingerprints</a> all over the planet’s warming, with the overwhelming majority of the evidence pointing to the extra greenhouse gases humans have put into the atmosphere by burning fossil fuels. Greenhouse gases like carbon dioxide <a href="http://climate.nasa.gov/causes">trap heat</a> at the Earth’s surface, preventing that heat from escaping back out into space too quickly. When we burn coal, natural gas, or oil for energy, or when we cut down forests that usually soak up greenhouse gases, we <a href="http://www.fas.org/sgp/crs/misc/RL34059.pdf">add even more</a> carbon dioxide to the atmosphere, so the planet warms up.</p>
<p id="YSRDN7">Global warming also refers to what scientists think will happen in the future if humans <em>keep</em> adding greenhouse gases to the atmosphere. </p>
<p id="KqWrle">Though there is a steady stream of new studies on climate change, one of the most robust aggregations of the science remains the Intergovernmental Panel on Climate Change’s <a href="http://www.ipcc.ch/report/ar5/wg1/">fifth assessment report</a> from 2013. The IPCC is convened by the United Nations, and the report draws on more than 800 expert authors. It <a href="http://www.vox.com/cards/global-warming/how-high-will-temperatures-rise-if-global-warming-continues">projects</a> that temperatures could rise at least 2°C (3.6°F) by the end of the century under many plausible scenarios — and possibly 4°C or more. A more recent <a href="https://www.nature.com/articles/nature25450.epdf?referrer_access_token=gpv6LEKDPKPeMABlJ6gB4tRgN0jAjWel9jnR3ZoTv0PyODaZGGnFL0k_aLNPU_eSZO_ob8Z2mlyde8dguBezZxtpDo_xF-Mqobj7RMKekx9HEqQcbG4OD6-kzo5_BB5p9U6XWYopgdiUf_L1zvgjEpIjm8XrnCm5AewdXD43gCmWJ6HdwLcXILvZTV2_1HYmQLLJretnrL0HKdAzLuOlxfrGaKkk4ZeSh6HW4EhtEjI%3D&tracking_referrer=www.wsj.com">study</a> by scientists in the United Kingdom found a narrower range of expected temperatures if atmospheric carbon dioxide doubled, rising between 2.2°C and 3.4°C.</p>
<p id="ymdSH7">Many experts consider 2°C of warming to be <a href="http://www.vox.com/cards/global-warming/why-dangerous-2-degrees-global-warming">unacceptably high</a>, increasing the risk of deadly heat waves, droughts, flooding, and extinctions. Rising temperatures will drive up global sea levels as the world’s glaciers and ice sheets melt. Further global warming <a href="http://www.vox.com/cards/global-warming/what-impacts-will-global-warming-have-in-the-future">could affect</a> everything from our ability to grow food to the spread of disease.</p>
<p id="pSNgAu">That’s why the IPCC put out another report in 2018 comparing 2°C of warming to a scenario with <a href="https://www.vox.com/2018/10/9/17951924/climate-change-global-warming-un-ipcc-report-takeaways">1.5°C of warming</a>. The researchers found that this half-degree difference is actually pretty important, since every bit of warming matters. Between the two outlooks, less warming means fewer people will have to move from coastal areas, natural weather events will be less severe, and economies will take a smaller hit. </p>
<p id="8jo53W">However, limiting warming would likely require a complete overhaul of our energy system. Fossil fuels currently <a href="https://data.worldbank.org/indicator/EG.USE.COMM.FO.ZS">provide just over 80 percent</a> of the world’s energy. To zero out emissions this century, we’d have to replace most of that with low-carbon sources like wind, solar, nuclear, geothermal, or carbon capture. </p>
<p id="O8m3ii">Beyond that, we may have to <a href="https://www.vox.com/2016/9/19/12938086/electrify-everything">electrify everything</a> that uses energy and start <a href="https://www.vox.com/energy-and-environment/2017/8/18/16166014/negative-emissions">pulling greenhouse gases</a> straight from the air. And to get on track for 1.5°C of warming, the world would have to halve greenhouse gas emissions from current levels by 2030. </p>
<p id="JfYUbR">That’s a staggering task, and there are huge technological and political hurdles standing in the way. As such, the world's nations have been slow to act on global warming — many of the existing targets for curbing greenhouse gas emissions are <a href="https://www.vox.com/energy-and-environment/2017/10/31/16579844/climate-gap-unep-2017">too weak</a>, yet many countries are <a href="https://www.vox.com/energy-and-environment/2017/10/31/16579844/climate-gap-unep-2017">falling short</a> of even these modest goals.</p>
<h3 id="gsLOkb">2) How do we know global warming is real?</h3>
<p id="h1WH22">The simplest way is through temperature measurements. Agencies in the United States, Europe, and Japan have <a href="http://www.cru.uea.ac.uk/cru/data/temperature/">independently</a> <a href="http://www.ncdc.noaa.gov/sotc/">analyzed</a> <a href="https://ds.data.jma.go.jp/tcc/tcc/products/gwp/temp/ann_wld.html">historical</a> temperature data and reached the same conclusion: The Earth’s average surface temperature has risen roughly 0.8° Celsius (1.4° Fahrenheit) since the early 20th century.</p>
<p id="VakBYE">But that’s not the only clue. Scientists have also noted that glaciers and ice sheets around the world are melting. Satellite observations since the 1970s have shown warming in the lower atmosphere. There’s more heat in the ocean, causing water to expand and sea levels to rise. Plants are <a href="https://ds.data.jma.go.jp/tcc/tcc/products/gwp/temp/ann_wld.html">flowering earlier</a> in many parts of the world. There’s more humidity in the atmosphere. <a href="http://www1.ncdc.noaa.gov/pub/data/cmb/bams-sotc/2009/bams-sotc-2009-chapter2-global-climate-lo-rez.pdf">Here’s</a> a summary from the National Oceanic and Atmospheric Administration:</p>
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<cite>NOAA</cite>
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<p id="k0faAF">These are all signs that the Earth really is getting warmer — and that it’s not just a glitch in the thermometers. That explains why climate scientists <a href="https://www.ipcc.ch/news_and_events/docs/ar5/press_release_ar5_wgi_en.pdf">say things like</a>, “Warming in the climate system is unequivocal.” They’re really confident about this one.</p>
<h3 id="QqsQK0">3) How do we know humans are causing global warming?</h3>
<p id="4Q2IbP">Climate scientists say they are more than <a href="http://www.climatechange2013.org/images/report/WG1AR5_SPM_FINAL.pdf">95 percent certain</a><strong> </strong>that human influence has been the dominant cause of global warming since 1950. They’re about <a href="http://bigstory.ap.org/article/what-95-certainty-warming-means-scientists">as sure of this</a> as they are that cigarette smoke causes cancer.</p>
<p id="8ACLJh">Why are they so confident? In part because they have a good grasp of how greenhouse gases can warm the planet, in part because the theory fits the available evidence, and in part because alternate theories have been ruled out. Let's break it down in six steps:</p>
<p id="kdiRLg">1) Scientists have long known that <a href="http://climate.nasa.gov/causes">greenhouse gases</a> in the atmosphere — such as carbon dioxide, methane, or water vapor — absorb certain frequencies of infrared radiation and <a href="http://www.ucsusa.org/global_warming/science_and_impacts/science/CO2-and-global-warming-faq.html">scatter them back</a> toward the Earth. These gases essentially prevent heat from escaping too quickly back into space, trapping that radiation at the surface and keeping the planet warm.</p>
<p id="zMxCr4">2) Climate scientists also know that concentrations of greenhouse gases in the atmosphere <a href="http://www.esrl.noaa.gov/gmd/ccgg/trends/">have grown significantly</a> since the Industrial Revolution. Carbon dioxide has risen <a href="https://www.reuters.com/article/us-climatechange-greenhouse/carbon-dioxide-levels-grew-at-record-pace-in-2016-u-n-says-idUSKBN1CZ0YB">45 percent</a>. Methane has risen more than <a href="https://www.epa.gov/climate-indicators/climate-change-indicators-atmospheric-concentrations-greenhouse-gases">200 percent</a>. Through some relatively straightforward <a href="http://www.esrl.noaa.gov/gmd/icdc7/proceedings/abstracts/keeling.rFF328Oral.pdf">chemistry</a> and <a href="https://www.esrl.noaa.gov/gmd/outreach/isotopes/mixing.html">physics</a>, scientists can trace these increases to human activities like burning oil, gas, and coal.</p>
<p id="qzJ2sz">3) So it stands to reason that more greenhouse gases would lead to more heat. And indeed, satellite measurements have shown that less infrared radiation is <a href="http://www.nature.com/nature/journal/v410/n6826/abs/410355a0.html">escaping out</a> into space over time and instead <a href="http://onlinelibrary.wiley.com/doi/10.1029/2009JD011800/abstract">returning</a> to the Earth’s surface. That’s strong evidence that the greenhouse effect is increasing.</p>
<div id="Ia1czA"><div style="left: 0; width: 100%; height: 0; position: relative; padding-bottom: 56.2493%;"><iframe src="https://www.youtube.com/embed/WEGwCPmELh8?rel=0&" style="border: 0; top: 0; left: 0; width: 100%; height: 100%; position: absolute;" allowfullscreen="" scrolling="no"></iframe></div></div>
<p id="6aCXzr">4) There are other <a href="http://www.skepticalscience.com/10-Indicators-of-a-Human-Fingerprint-on-Climate-Change.html">human fingerprints</a> that suggest increased greenhouse gases are warming the planet. For instance, back in the 1960s, simple climate models predicted that global warming caused by more carbon dioxide would lead to cooling in the upper atmosphere (because the heat is getting trapped at the surface). Later satellite measurements confirmed <a href="http://www.agu.org/pubs/crossref/2003/2002GL016377.shtml">exactly that</a>. Here are <a href="http://www.knmi.nl/publications/showAbstract.php?id=706">a few</a> other <a href="http://www.math.nyu.edu/~gerber/pages/documents/santer_etal-science-2003.pdf">similar</a> <a href="http://www.ufa.cas.cz/html/climaero/topics/global_change_science.pdf">predictions</a> that have also been confirmed. </p>
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<img alt=" " data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/siploQ9ntxCaZr5kHlm2seCDczM=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/8613609/HumansGW.jpg">
<cite><a href="http://www.skepticalscience.com/10-Indicators-of-a-Human-Fingerprint-on-Climate-Change.html"><strong>Skeptical Science</strong></a></cite>
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<p id="VfI2ig">5) Meanwhile, climate scientists have ruled out other explanations for the rise in average temperatures over the past century. To take one example: Solar activity can shift from year to year, affecting the Earth's climate. But satellite data shows that total solar irradiance <a href="http://www.skepticalscience.com/solar-activity-sunspots-global-warming-basic.htm">has declined slightly</a> in the past 35 years, even as the Earth has warmed.</p>
<p id="VK3XSC">6) More <a href="http://www.pnas.org/content/early/2013/09/10/1305332110.abstract">recent calculations</a> have shown that it’s impossible to explain the temperature rise we’ve seen in the past century without taking the increase in carbon dioxide and other greenhouse gases into account. Natural causes, like the sun or volcanoes, have an influence, but they’re not sufficient by themselves.</p>
<p id="aSIeh8">Ultimately, the Intergovernmental Panel on Climate Change <a href="http://www.climatechange2013.org/images/report/WG1AR5_SPM_FINAL.pdf">concluded</a> that most of the warming since 1951 has been due to human activities. The Earth’s climate can certainly fluctuate from year to year due to natural forces (including oscillations in the Pacific Ocean, such as <a href="http://en.wikipedia.org/wiki/El_Ni%C3%B1o%E2%80%93Southern_Oscillation">El Niño</a>). But greenhouse gases are driving the larger upward trend in temperatures.</p>
<p id="c8sgZ7">And as the <a href="https://science2017.globalchange.gov/">Climate Science Special Report</a>, released by 13 US federal agencies in November 2017, put it, “For the warming over the last century, there is no convincing alternative explanation supported by the extent of the observational evidence.”</p>
<p id="98YJYO">More: <a href="http://www.realclimate.org/index.php/archives/2013/10/the-evolution-of-radiative-forcing-bar-charts/">This chart</a> breaks down all the different factors affecting the Earth’s average temperature. And there’s much more detail in the IPCC’s <a href="http://www.google.com/url?q=http%3A%2F%2Fwww.climatechange2013.org%2Fimages%2Freport%2FWG1AR5_SPM_FINAL.pdf&sa=D&sntz=1&usg=AFQjCNHIz6BWj9eiHexaqRmbade5-Vh-YQ">report</a>, particularly <a href="http://www.google.com/url?q=http%3A%2F%2Fwww.climatechange2013.org%2Fimages%2Freport%2FWG1AR5_Chapter08_FINAL.pdf&sa=D&sntz=1&usg=AFQjCNHC_Ue87V-TVDRujUOVvGohEtl8Kg">this section</a> and <a href="http://www.google.com/url?q=http%3A%2F%2Fwww.climatechange2013.org%2Fimages%2Freport%2FWG1AR5_Chapter10_FINAL.pdf&sa=D&sntz=1&usg=AFQjCNHMijN15A8A0gb8S5xpASqeS3dgow">this one</a>.</p>
<h3 id="u69wNz">4) How has global warming affected the world so far?</h3>
<p id="RYEkxC">Here’s a list of ongoing changes that climate scientists have concluded are likely linked to global warming, as detailed by the IPCC <a href="https://www.ipcc.ch/report/ar5/wg1/">here</a> and <a href="https://www.ipcc.ch/working-group/wg2/">here</a>.</p>
<p id="52hZly"><strong>Higher temperatures:</strong> Every continent has warmed substantially since the 1950s. There are <a href="https://www.nytimes.com/interactive/2017/07/28/climate/more-frequent-extreme-summer-heat.html">more hot days</a> and fewer cold days, on average, and the hot days are hotter.</p>
<p id="1hU1q0"><strong>Heavier storms</strong><strong> and floods</strong><strong>:</strong> The world’s atmosphere can hold more moisture as it warms. As a result, the overall number of heavier storms has <a href="https://www.vox.com/energy-and-environment/2017/9/28/16362522/hurricane-maria-2017-irma-harvey-rain-flooding-climate-change">increased</a> since the mid-20th century, particularly in North America and Europe (though there’s plenty of regional variation). Scientists reported in December that at least <a href="http://onlinelibrary.wiley.com/doi/10.1002/2017GL075888/full">18 percent</a> of Hurricane Harvey’s record-setting rainfall over Houston in August was due to climate change. </p>
<p id="nrdi7X"><strong>Heat waves:</strong> Heat waves have become <a href="http://www.climatechange2013.org/images/report/WG1AR5_Chapter02_FINAL.pdf">longer and more frequent</a> around the world over the past 50 years, particularly in Europe, Asia, and Australia.</p>
<p id="vJRXnt"><strong>Shrinking sea ice:</strong> The extent of sea ice in the Arctic, always at its maximum in winter, has shrunk since 1979, by <a href="http://nsidc.org/arcticseaicenews/">3.3 percent</a> per decade. Summer sea ice has dwindled even more rapidly, by <a href="https://climate.nasa.gov/vital-signs/arctic-sea-ice/">13.2 percent</a> per decade. Antarctica has seen recent years with <a href="https://www.nasa.gov/content/goddard/antarctic-sea-ice-reaches-new-record-maximum">record growth</a> in sea ice, but it’s a very different environment than the Arctic, and the losses in the north far exceed any gains at the South Pole, so total global sea ice is on the decline:</p>
<div id="SpWuq3">
<blockquote class="twitter-tweet">
<p lang="ro" dir="ltr">Global, Arctic and Antarctic Sea Ice Area Spiral February 2018 <a href="https://twitter.com/hashtag/GlobalWarming?src=hash&ref_src=twsrc%5Etfw">#GlobalWarming</a> <a href="https://twitter.com/hashtag/ClimateChange?src=hash&ref_src=twsrc%5Etfw">#ClimateChange</a> <a href="https://t.co/gayoLFSJ5u">pic.twitter.com/gayoLFSJ5u</a></p>— Kevin Pluck (@kevpluck) <a href="https://twitter.com/kevpluck/status/969319123678322688?ref_src=twsrc%5Etfw">March 1, 2018</a>
</blockquote>
<script async="" src="https://platform.twitter.com/widgets.js" charset="utf-8"></script>
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<p id="MV7X8Z"><strong>Shrinking glaciers</strong><strong> and ice sheets</strong><strong>:</strong> Glaciers around the world have, on average, been losing ice since the 1970s. In some areas, that <a href="http://ipcc-wg2.gov/AR5/images/uploads/IPCC_WG2AR5_SPM_Approved.pdf">is reducing</a> the amount of available freshwater. The ice sheet on Greenland, which would raise global sea levels by 25 feet if it all melted, is declining, with some sections experiencing a <a href="https://www.vox.com/energy-and-environment/2017/12/14/16772722/greenland-ice-sheet-melting-sea-level-rise">sudden surge</a> in the melt rate. The Antarctic ice sheet is also getting smaller, but at a much <a href="https://nsidc.org/cryosphere/quickfacts/icesheets.html">slower rate</a>. </p>
<p id="78CeJe"><strong>Sea</strong><strong> </strong><strong>level rise:</strong> Global sea levels rose 9.8 inches (25 centimeters) in the 19th and 20th centuries, after 2,000 years <a href="http://www.climatechange2013.org/images/report/WG1AR5_Chapter13_FINAL.pdf">of relatively little change</a>, and the pace is <a href="https://sealevel.nasa.gov/news/108/new-study-finds-sea-level-rise-accelerating">speeding up</a>. Sea level rise is caused by both the thermal expansion of the oceans — as water warms up, it expands — and the melting of glaciers and ice sheets (but not sea ice).</p>
<p id="MfVGli"><strong>Food supply:</strong> A hotter climate can be both good for crops (it lengthens the growing season, and more carbon dioxide can increase photosynthesis) and bad for crops (excess heat can damage plants). The IPCC <a href="http://ipcc-wg2.gov/AR5/images/uploads/WGIIAR5-Chap7_FGDall.pdf">found</a> that global warming was currently benefiting crops in some high-latitude areas but that negative effects are becoming increasingly common worldwide. In areas like California, crop yields are estimated to decline <a href="http://www.mdpi.com/2073-4395/8/3/25/htm">40 percent</a> by 2050. </p>
<p id="UgTW2R"><strong>Shifting species:</strong> Many land and marine species <a href="http://ipcc-wg2.gov/AR5/images/uploads/IPCC_WG2AR5_SPM_Approved.pdf">have had to shift</a> their geographic ranges in response to warmer temperatures. So far, several extinctions <a href="http://ipcc-wg2.gov/AR5/images/uploads/WGIIAR5-Chap4_FGDall.pdf">have been linked</a> to global warming, such as certain frog species in Central America.</p>
<p id="QdJnee"><strong>Warmer winters: </strong>In general, <a href="https://www.vox.com/science-and-health/2018/12/20/18136006/climate-change-warmer-winters">winters are warming faster than summers</a>. Average low temperatures are rising all over the world. In some cases, these temperatures are climbing above the freezing point of water. We’re already seeing massive declines in snow accumulation in the United States, which can paradoxically increase flood, drought, and wildfire risk — as water that would ordinarily dispatch slowly over the course of a season instead flows through a region all at once. </p>
<h4 id="rUtUT1">Debated impacts</h4>
<p id="IU1zhW">Here are a few other ways the Earth’s climate has been changing — but scientists are still debating whether and how they’re linked to global warming:</p>
<p id="IfvybG">Droughts have become <a href="http://www.climatechange2013.org/images/report/WG1AR5_Chapter02_FINAL.pdf">more frequent and more intense</a> in some parts of the world — such as the American Southwest, Mediterranean Europe, and West Africa — though it’s hard to identify a clear global trend. In other parts of the world, such as the Midwestern United States and Northwestern Australia, droughts appear to have become <em>less</em> frequent. A recent <a href="https://www.nature.com/articles/nature23021">study</a> shows that, globally, the time between droughts is shrinking and more areas are affected by drought and taking longer to recover from them.</p>
<p id="973Nq5">Hurricanes have clearly become more intense in the North Atlantic Ocean since 1970, the IPCC says. But it’s less clear whether global warming is driving this. 2017 was an <a href="https://www.vox.com/energy-and-environment/2017/12/28/16795490/natural-disasters-2017-hurricanes-wildfires-heat-climate-change-cost-deaths">exceptionally bad</a> year for Atlantic hurricanes in terms of strength and damage. And while scientists are still uncertain whether they were a fluke or part of a trend, they <a href="https://www.vox.com/energy-and-environment/2017/10/25/16504488/hurricane-season-2017-what-the-hell">are warning</a> we should treat it as a baseline year. <a href="http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-11-00719.1">There doesn’t yet seem to be</a> any clear trajectory for tropical cyclones worldwide.</p>
<h3 id="1VV4La">5) What impacts will global warming have in the future?</h3>
<p id="B1gg74">It depends on how much the planet actually heats up. The changes associated with 4° Celsius (or 7.2° Fahrenheit) of warming are expected to be more dramatic than the changes associated with 2°C of warming.</p>
<p id="dVJwpn">Here’s a basic rundown of big impacts we can expect if global warming continues, via the IPCC (<a href="https://www.ipcc.ch/report/ar5/wg1/"><strong>here</strong></a> and <a href="https://www.ipcc.ch/working-group/wg2/"><strong>here</strong></a>).</p>
<p id="p1cJ2D"><strong>Hotter temperatures:</strong> If emissions keep rising unchecked, then global average surface temperatures will be at least 2°C higher (3.6°F) than preindustrial levels by 2100 — and possibly 3°C or 4°C or more.</p>
<p id="jw3js5"><strong>Higher sea</strong><strong> </strong><strong>level rise:</strong> The expert consensus is that global sea levels will rise somewhere between <a href="https://sealevel.nasa.gov/understanding-sea-level/projections/empirical-projections">0.2 and 2 meters</a> by the end of the century if global warming continues unchecked (that’s between 0.6 and 6.6 feet). That’s a wide range, reflecting some of the uncertainties scientists have in how ice will melt. In specific regions like the Eastern United States, sea level rise could be even higher, and around the world, the rate of rise is <a href="https://sealevel.nasa.gov/news/108/new-study-finds-sea-level-rise-accelerating">accelerating</a>. </p>
<p id="QE1XFb"><strong>Heat waves:</strong> A hotter planet will mean more frequent and severe <a href="https://www.epa.gov/heat-islands/climate-change-and-heat-islands">heat waves</a>.</p>
<p id="vBlc2k"><strong>Droughts and floods:</strong> Across the globe, wet seasons are expected to become wetter, and dry seasons drier. As the IPCC <a href="http://www.climatechange2013.org/images/report/WG1AR5_Chapter12_FINAL.pdf"><strong>puts it</strong></a>, the world will see “more intense downpours, leading to more floods, yet longer dry periods between rain events, leading to more drought.”</p>
<p id="FbGUvK"><strong>Hurricanes:</strong> It’s not yet clear what impact global warming will have on tropical cyclones. The IPCC <a href="http://www.climatechange2013.org/images/uploads/WGIAR5_WGI-12Doc2b_FinalDraft_Chapter14.pdf"><strong>said</strong></a> it was likely that tropical cyclones would get stronger as the oceans heat up, with faster winds and heavier rainfall. But the overall number of hurricanes in many regions was likely to “either decrease or remain essentially unchanged.”</p>
<p id="df61VQ"><strong>Heavier storm surges:</strong> Higher sea levels will <a href="http://www.washingtonpost.com/blogs/wonkblog/wp/2012/10/29/yes-hurricane-sandy-is-a-good-reason-to-worry-about-climate-change/"><strong>increase the risk of storm surges</strong></a> and flooding when storms do hit.</p>
<p id="w1yBPH"><strong>Agriculture:</strong> In many parts of the world, the mix of increased heat and drought is expected to make food production more difficult. The IPCC <a href="https://www.ipcc.ch/site/assets/uploads/2018/02/WGIIAR5-Chap7_FINAL.pdf"><strong>concluded</strong></a> that global warming of 1°C or more could start hurting crop yields for wheat, corn, and rice by the 2030s, especially in the tropics. (This wouldn’t be uniform, however; some crops may benefit from mild warming, such as winter wheat in the United States.)</p>
<figure class="e-image">
<img alt=" " data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/Cj6CsSWCD2nqzAKlpd5_cfEbS14=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/8613683/WGII_AR5_Fig7_4.jpg">
<cite>IPCC</cite>
</figure>
<p id="hfD7kB"><strong>Extinctions:</strong> As the world warms, many plant and animal species will need to shift habitats at a rapid rate to maintain their current conditions. Some species will be able to keep up; others likely won’t. The Great Barrier Reef, for instance, may not be able to <a href="https://www.vox.com/science-and-health/2017/4/18/15272634/catastrophic-coral-bleaching-great-barrier-reef-map">recover</a> from major recent bleaching events linked to climate change. The National Research Council <a href="http://www.washingtonpost.com/blogs/wonkblog/wp/2013/12/04/what-surprises-could-climate-change-have-in-store-for-us/"><strong>has estimated</strong></a> that a mass extinction event “could conceivably occur before the year 2100.”</p>
<p id="u5IIRC"><strong>Long-term changes:</strong> Most of the projected changes above will occur in the 21st century. But temperatures will keep rising after that if greenhouse gas levels aren’t stabilized. That increases the risk of more drastic longer-term shifts. One example: If West Antarctica’s ice sheet started crumbling, that could push sea levels up significantly. The National Research Council in 2013 <a href="http://www.washingtonpost.com/blogs/wonkblog/wp/2013/12/04/what-surprises-could-climate-change-have-in-store-for-us/"><strong>deemed</strong></a> many of these rapid climate surprises unlikely this century but a real possibility further into the future.</p>
<h3 id="5f7F8s">6) What happens if the world heats up more drastically — say, 4°C?</h3>
<p id="b0gHkS">The risks of climate change would rise considerably if temperatures rose 4° Celsius (7.2° Fahrenheit) above preindustrial levels — something that’s possible if greenhouse gas emissions keep rising at their current rate.</p>
<p id="FX4vKB">The IPCC <a href="https://www.ipcc.ch/site/assets/uploads/2018/02/ar5_wgII_spm_en.pdf"><strong>says</strong></a> 4°C of global warming could lead to “substantial species extinctions,” “large risks to global and regional food security,” and the risk of irreversibly destabilizing Greenland’s massive ice sheet.</p>
<p id="c3UyYj">One huge concern is food production: A <a href="http://www.nature.com/nclimate/journal/v2/n3/full/nclimate1356.html"><strong>growing</strong></a> <a href="http://www.ocf.berkeley.edu/~marshall/papers/Hertel_etal_GEC_2010.pdf"><strong>number</strong></a> of <a href="http://iopscience.iop.org/1748-9326/5/1/014010"><strong>studies</strong></a><strong> </strong>suggest it would become significantly more difficult for the world to grow food with 3°C or 4°C of global warming. Countries like Bangladesh, Egypt, Vietnam, and parts of Africa could see large tracts of farmland turn unusable due to rising seas. Scientists are also concerned about crops <a href="https://www.politico.com/agenda/story/2017/09/13/food-nutrients-carbon-dioxide-000511">getting less nutritious</a> due to rising CO2.</p>
<p id="LDPdTs">Humans could struggle to adapt to these conditions. Many people might think the impacts of 4°C of warming will simply be twice as bad as those of 2°C. But as a 2013 <a href="http://www.worldbank.org/en/topic/climatechange/publication/turn-down-the-heat-climate-extremes-regional-impacts-resilience">World Bank</a> report argued, that’s not necessarily true. Impacts may interact with each other in unpredictable ways. Current agriculture models, for instance, don’t have a good sense of what will happen to crops if increased heat waves, droughts, new pests and diseases, and other changes all start to combine.</p>
<p id="z0C9GU">“Given that uncertainty remains about the full nature and scale of impacts,” the World Bank report said, “there is also no certainty that adaptation to a 4°C world is possible.” Its conclusion was blunt: “The projected 4°C warming simply must not be allowed to occur.”</p>
<h3 id="sYCnAv">7) What do climate models say about the warming that could actually happen in the coming decades?</h3>
<p id="EvilFF">That depends on your faith in humanity. </p>
<p id="IYUnAE">Climate models depend on not only complicated physics but the intricacies of human behavior over the entire planet. </p>
<p id="nFIARs">Generally, the more greenhouse gases humanity pumps into the atmosphere, the warmer it will get. But scientists aren’t certain how sensitive the global climate system is to increases in greenhouse gases. And just how much we might emit over the coming decades remains an open question, depending on advances in technology and international efforts to cut emissions.</p>
<p id="d7T5t7">The IPCC groups these scenarios into four categories of atmospheric greenhouse gas concentrations known as <a href="http://sedac.ipcc-data.org/ddc/ar5_scenario_process/RCPs.html">Representative Concentration Pathways</a>. They serve as standard benchmarks for evaluating climate models, but they also have some assumptions <a href="https://www.sei-international.org/mediamanager/documents/A-guide-to-RCPs.pdf">baked in</a>. </p>
<p id="uBVEmF">RCP 2.6, also called RCP 3PD, is the scenario with very low greenhouse gas concentrations in the atmosphere. It bets on declining oil use, a population of 9 billion by 2100, increasing energy efficiency, and emissions holding steady until 2020, at which point they’ll decline and even go negative by 2100. This is, to put it mildly, very optimistic.</p>
<p id="P29Tv3">The next tier up is RCP 4.5, which still banks on ambitious reductions in emissions but anticipates an inflection point in the emissions rate around 2040. RCP 6 expects emissions to increase 75 percent above today’s levels before peaking and declining around 2060 as the world continues to rely heavily on fossil fuels. </p>
<p id="7NeBIQ">The highest tier, RCP 8.5, is the pessimistic business-as-usual scenario, anticipating no policy changes nor any technological advances. It expects a global population of 12 billion and triple the rate of carbon dioxide emissions compared to today by 2100. </p>
<p id="KAkWp8">Here’s how greenhouse gas emissions under each scenario stack up next to each other:</p>
<figure class="e-image">
<img alt=" " data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/RPXuaC8w9ju6oB25P1dsEwGeExg=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/10350069/RCP_IEA_Emissions.jpg">
<cite><a href="https://skepticalscience.com/climate-best-to-worst-case-scenarios.html">Skeptical Science</a></cite>
</figure>
<p id="4Lc3kn">And here’s what that means for global average temperatures, assuming that a doubling of carbon dioxide concentrations in the atmosphere leads to 3°C of warming:</p>
<figure class="e-image">
<img alt=" " data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/1bHBe8eN0m0rdYocgCGaEoT0NYM=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/10350081/3C_Sensitivity.jpg">
<cite><a href="https://skepticalscience.com/climate-best-to-worst-case-scenarios.html">Skeptical Science</a></cite>
</figure>
<p id="xwnxut">As you can see, RCP 3PD is the only trajectory that keeps the planet below 2°C of warming. Recall what it would take to keep emissions in line with this pathway and you’ll understand the enormity of the challenge of meeting this goal. </p>
<h3 id="w1SIk4">8) How do we stop global warming?</h3>
<p id="6s3tlf">The world’s nations would <a href="http://www.vox.com/2014/4/13/5610356/un-panel-heres-how-we-cut-emissions-and-avoid-a-climate-disaster"><strong>need to cut</strong></a> their greenhouse gas emissions by a lot. And even that wouldn’t stop all global warming.</p>
<p id="fXIu9r">For example, let’s say we wanted to limit global warming to below 2°C. To do that, the IPCC <a href="http://www.vox.com/2014/11/2/7146215/ipcc-climate-change-synthesis-report-phasing-out-fossil-fuels"><strong>has calculated</strong></a> that annual greenhouse gas emissions would need to drop at least 40 to 70 percent by midcentury.</p>
<p id="d9AShl">Emissions would then have to keep falling until humans were hardly emitting any extra greenhouse gases by the end of the century. We’d also have to remove <a href="https://www.vox.com/energy-and-environment/2017/8/18/16166014/negative-emissions"><strong>carbon dioxide from the atmosphere</strong></a>. </p>
<p id="7QhsO8">Cutting emissions that sharply is a daunting task. Right now, the world gets <a href="http://www.vox.com/2014/6/19/5821250/these-5-charts-show-why-the-world-is-still-failing-on-climate-change"><strong>87 percent</strong></a> of its primary energy from fossil fuels: oil, gas, and coal. By contrast, just 13 percent of the world’s primary energy is “low carbon”: a little bit of wind and solar power, some nuclear power plants, a bunch of hydroelectric dams. That’s one reason global emissions keep rising each year.</p>
<p id="H2qko1">To stay below 2°C, that would all need to change radically. By 2050, the IPCC notes, the world would need to triple or even quadruple the share of clean energy it uses — and keep scaling it up thereafter. Second, we’d have to get dramatically more efficient at using energy in our homes, buildings, and cars. And stop cutting down forests. And reduce emissions from agriculture and from industrial processes like cement manufacturing.</p>
<p id="dPgLoH">The IPCC also notes that this task becomes even more difficult the longer we put it off, because carbon dioxide and other greenhouse gases will keep piling up in the atmosphere in the meantime, and the cuts necessary to stay below the 2°C limit become more severe.</p>
<h3 id="nSrQyp">9) What are we actually doing to fight climate change?</h3>
<p id="IkXfKO">A global problem requires global action, but with climate change, there is a yawning gap between ambition and action. </p>
<p id="tCqSF4">The main international effort is the 2015 Paris climate accord, of which the United States is the only country in the world that <a href="https://www.vox.com/energy-and-environment/2017/11/7/16617612/united-states-paris-climate-accords">wants out</a>. The deal was hammered out over weeks of tense negotiations and weighs in at <a href="https://unfccc.int/resource/docs/2015/cop21/eng/l09.pdf">31 pages</a>. What it does is actually pretty simple. </p>
<p id="WXw2rE">The backbone is the global target of keeping global average temperatures from <a href="https://www.vox.com/2014/4/22/5551004/two-degrees">rising 2°C</a> (compared to temperatures before the Industrial Revolution) by the end of the century. Beyond 2 degrees, we risk dramatically higher seas, changes in weather patterns, food and water crises, and an overall more hostile world. </p>
<p id="Grlrqu">Critics have argued that the 2-degree mark is arbitrary, <a href="https://www.vox.com/2014/4/22/5551004/two-degrees">or even too low</a>, to make a difference. But it’s a starting point, a goal that, before Paris, the world was on track to wildly miss. </p>
<figure class="e-image">
<img alt=" " data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/cBqsS1HmGih6AR9YmsS7Ds-2gqI=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/7291239/global_CO2_emissions_graphic.jpg">
<cite>(Javier Zarracina/Vox)</cite>
</figure>
<p id="DfMMyZ"><strong>Paris is voluntary </strong></p>
<p id="gQc2rO">To accomplish this 2-degree goal, the accord states that countries should strive to reach peak emissions “as soon as possible.” (Currently, <a href="https://www.vox.com/2015/12/12/9981020/paris-climate-deal">we’re on track to hit peak emissions around 2030 or later</a>, which will likely be too late.) </p>
<p id="tqnSyo">But the agreement doesn’t detail exactly how these countries should do that. Instead, it provides a framework for getting momentum going on greenhouse gas reduction, with some oversight and accountability. For the US, the pledge involves 26 to 28 percent reductions by 2025. (Under Trump’s current policies, that goal <a href="https://www.vox.com/energy-and-environment/2017/5/25/15689200/trump-policy-carbon-emissions-graph">is impossible</a>.)</p>
<p id="2JoP46">There’s also no defined punishment for breaking it. The idea is to create a culture of accountability (and maybe some peer pressure) to get countries to step up their climate game. </p>
<p id="6fiTfg">In 2020, delegates are supposed to reconvene and provide updates about their emission pledges and report on how they’re becoming more aggressive on accomplishing the 2-degree goal. </p>
<p id="q2cL2f">However, many countries are already <a href="http://www.dw.com/en/climate-change-world-way-off-track-on-paris-accord-goals/a-41173220">falling behind</a> on their climate change commitments, and some, like Germany, are <a href="https://www.politico.eu/article/report-german-parties-agree-to-drop-2020-climate-goal/">giving up</a> on their near-term targets. </p>
<p id="OrmgVs"><strong>Paris asks richer countries to help out poorer countries </strong></p>
<p id="qfC01w">There’s a fundamental inequality when it comes to global emissions. Rich countries have plundered and burned huge amounts of fossil fuels and gotten rich from them. Poor countries seeking to grow their economies are now being admonished for using the same fuels. Many low-lying poor countries also will be among the first to bear the worst impacts of climate change. </p>
<p id="eEex5P">The main vehicle for rectifying this is the <a href="https://www.greenclimate.fund/home">Green Climate Fund</a>, via which richer countries, like the US, are supposed to send $100 billion a year in aid and financing by 2020 to the poorer countries. The United States’ share was <a href="https://www.washingtonpost.com/posteverything/wp/2017/06/02/trump-will-stop-paying-into-the-green-climate-fund-he-has-no-idea-what-it-is/?utm_term=.26d94d4eb9b2">$3 billion</a>, but with President Trump’s decision to withdraw from the Paris accord, this goal is unlikely to be met. </p>
<p id="nHrDJr"><strong>The agreement matters because we absolutely need momentum on this issue </strong></p>
<p id="KZAxgg">The Paris agreement is largely symbolic, and it will live on<strong> </strong>even though Trump is aiming to pull the US out. But, as Jim Tankersley <a href="https://www.vox.com/2017/5/31/15719386/trump-paris-climate-agreement-moral-failure">wrote for Vox</a>, “the accord will be weakened, and, much more importantly, so will the fragile international coalition” around climate change.</p>
<p id="DGb6d7">We’re already seeing the Paris agreement lose steam. At a follow-up climate meeting this year in <a href="https://www.vox.com/energy-and-environment/2018/12/14/18139402/cop24-climate-change-katowice-poland">Katowice, Poland</a>, negotiators forged an agreement on measuring and verifying their progress in cutting greenhouse gases, but left many critical questions of <em>how </em>to achieve these reductions unanswered. </p>
<p id="nl7hY2"><strong>But the Paris accord isn’t the only </strong><strong>international climate policy game</strong><strong> in town</strong></p>
<p id="TMmxir">There are regional international climate efforts like the European Union’s <a href="https://ec.europa.eu/clima/policies/ets_en">Emissions Trading System</a>. However, the most effective global policy at keeping warming in check to date doesn’t have to do with climate change, at least on the surface. </p>
<p id="4BleWV">The 1987 <a href="https://www.vox.com/energy-and-environment/2017/11/28/16705462/montreal-protocol-trump-treaty-climate-change-ozone">Montreal Protocol</a>, which was convened by countries to halt the destruction of the ozone layer, had a major side effect of averting warming. In fact, it’s been the single most effective effort humanity has undertaken to fight climate change. Since many of the substances that eat away at the ozone layer are potent heat-trappers, limiting emissions of gases like chlorofluorocarbons has an outsize effect.</p>
<figure class="e-image">
<img alt=" " data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/9byJKkeGIKae1SVndnmz9yj_cTI=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/10354423/Screen_Shot_2017_11_27_at_2.33.42_PM.png">
<cite><a href="https://www.economist.com/news/briefing/21618680-our-guide-actions-have-done-most-slow-global-warming-deepest-cuts">The Economist</a></cite>
</figure>
<p id="wpiShV">And the Trump administration doesn’t appear as hostile to Montreal as it does to Paris. The White House may send the 2016 <a href="https://www.unenvironment.org/news-and-stories/news/kigali-amendment-montreal-protocol-another-global-commitment-stop-climate">Kigali Amendment</a> to the Montreal Protocol to the Senate for ratification, giving the new regulations the force of law. If implemented, the amendment would avert 0.5°C of warming by 2100. </p>
<p id="ggXUFn">Regardless of what path we choose, the key thing to remember is that we are going to pay for climate change one way or another. We have the opportunity now to address warming on our own terms, with investments in clean energy, moving people away from disaster-prone areas, and regulating greenhouse gas emissions. Otherwise, we’ll pay through diminished crop harvests, inundated coastlines, destroyed homes, lost lives, and an increasingly unlivable planet. Ignoring or stalling on climate change chooses the latter option by default. Our choices do matter, but we’re running out of time to make them. </p>
<h3 id="TfM36B">
<strong>F</strong><strong>urther reading:</strong>
</h3>
<p id="c1CpHu"><a href="https://www.vox.com/energy-and-environment/2017/9/19/16324926/avoiding-catastrophic-climate-change">Avoiding catastrophic climate change isn’t impossible yet. Just incredibly hard.</a></p>
<p id="rUU4yi"><a href="https://www.vox.com/energy-and-environment/2018/1/27/16935382/climate-change-ugly-tradeoffs">Reckoning with climate change will demand ugly tradeoffs from environmentalists — and everyone else</a></p>
<p id="CWW6sT"><a href="https://www.vox.com/energy-and-environment/2016/10/17/13190036/global-climate-change-facts-effects-cartoon">Show this cartoon to anyone who doubts we need huge action on climate change</a></p>
<p id="CVosRm"><a href="https://www.vox.com/energy-and-environment/2017/8/18/16166014/negative-emissions">It’s time to start talking about “negative” carbon dioxide emissions</a></p>
<p id="8PMNzP"><a href="http://www.vox.com/2014/4/22/5551004/two-degrees">A history of the 2°C global warming target</a> </p>
<p id="aABPA2"><a href="https://www.vox.com/energy-and-environment/2017/3/23/15028480/roadmap-paris-climate-goals">Scientists made a detailed “roadmap” for meeting the Paris climate goals. It’s eye-opening.</a></p>
<p id="heto7G"></p>
https://www.vox.com/science-and-health/2017/6/1/15724164/9-questions-climate-change-too-embarrassed-to-askBrad PlumerBrian ResnickUmair Irfan2018-12-27T14:45:45-05:002018-12-27T14:45:45-05:00A simple guide to CRISPR, one of the biggest science stories of the decade
<figure>
<img alt="" src="https://cdn.vox-cdn.com/thumbor/aR9huKxMUwVTJhagrr2RAsC7_fQ=/300x0:2700x1800/1310x983/cdn.vox-cdn.com/uploads/chorus_image/image/60457725/CRISPR_LEAD.0.jpg" />
</figure>
<p>It could revolutionize everything from medicine to agriculture. Better read up now.</p> <p id="2qgCoZ">One of the biggest and most important science stories of the past few years will probably also be one of the biggest science stories of the next few years. So this is as good a time as any to get acquainted with the powerful new gene editing technology known as CRISPR.</p>
<p id="Gd6aa1">If you haven’t heard of <a href="https://en.wikipedia.org/wiki/CRISPR">CRISPR</a> yet, the short explanation goes like this: In the past nine years, scientists have figured out how to exploit a quirk in the immune systems of bacteria to edit genes in other<em> </em>organisms — plants, mice, even humans. With CRISPR, they can now make these edits quickly and cheaply, in days rather than weeks or months. (The technology is often known as CRISPR/Cas9, but we’ll stick with CRISPR, pronounced “crisper.”)</p>
<p id="abSEr5">We’re talking about a powerful new tool to control which genes get expressed in plants, animals, and even humans; the ability to delete undesirable traits and, potentially, add desirable traits with more precision than ever before. </p>
<p id="L3P2cE">So far scientists have used it to <a href="https://www.nature.com/articles/nature25164">reduce the severity of genetic deafness</a> in mice, suggesting it could one day be used to treat the same type of hearing loss in people. They’ve created <a href="http://www.npr.org/sections/thesalt/2016/04/15/474358416/will-genetically-edited-food-be-regulated-the-case-of-the-mushroom">mushrooms that don’t brown easily</a> and edited bone marrow cells in mice to <a href="https://www.wired.com/2016/11/blood-diseases-show-crisprs-potential-therapy/">treat sickle-cell anemia</a>. Down the road, CRISPR might help us develop drought-tolerant crops and create powerful new antibiotics. CRISPR could one day even allow us to <a href="http://www.vox.com/2016/6/9/11890472/gene-drive-benefits-risk">wipe out entire populations of </a><a href="https://www.vox.com/science-and-health/2018/5/31/17344406/crispr-mosquito-malaria-gene-drive-editing-target-africa-regulation-gmo">malaria-spreading mosquitoes</a> or <a href="http://www.sciencemag.org/news/2016/09/should-we-bring-extinct-species-back-dead">resurrect once-extinct species</a> like the passenger pigeon. </p>
<p id="ovpMvK">A big concern is that while CRISPR is relatively simple and powerful, it isn’t perfect. Scientists have recently learned that the approach to gene editing can inadvertently <a href="https://www.nature.com/articles/nbt.4192">wipe out and rearrange large swaths of DNA</a> in ways that may <a href="https://www.statnews.com/2018/07/16/crispr-potential-dna-damage-underestimated/">imperil human health</a>. That follows recent studies showing that CRISPR-edited cells can inadvertently <a href="https://www.statnews.com/2018/06/11/crispr-hurdle-edited-cells-might-cause-cancer/">trigger cancer</a>. That’s why many scientists argue that experiments in humans are premature: The risks and uncertainties around CRISPR modification are extremely high. </p>
<p id="kIwD1o">On this front, 2018 brought some shocking news: In November, a scientist in China, He Jiankui, reported that he had created the world’s first <a href="https://www.vox.com/science-and-health/2018/11/30/18119589/crispr-technology-he-jiankui">human babies</a> with CRISPR-edited genes: a pair of twin girls resistant to HIV. </p>
<p id="Rc5Ez4">The announcement stunned scientists around the world. The director of the National Institutes of Health, Francis Collins, said the experiment was “<a href="https://twitter.com/NIHDirector/status/1067809726489141253">profoundly disturbing and tramples on ethical norms</a>.”</p>
<p id="VZapWm">It also created more questions than it answered: Did Jiankui actually pull it off? Does he deserve praise or condemnation? Do we need to pump the brakes on CRISPR research?</p>
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<p id="4c6RDk">While independent researchers have not yet confirmed that Jiankui was successful, there are other CRISPR applications that are close to fruition from new disease therapies to novel tactics for fighting malaria. So here’s a basic guide to what CRISPR is and what it can do.</p>
<h3 id="5KYunY">What the heck is CRISPR, anyway?</h3>
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<p id="iSNPTs">If we want to understand CRISPR, we should go back to 1987, when Japanese scientists studying E. coli<em> </em>bacteria<em> </em>first came across some unusual repeating sequences in the organism’s DNA. “The biological significance of these sequences,” <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC213968/pdf/jbacter00202-0107.pdf">they wrote</a>, “is unknown.” Over time, other researchers <a href="https://www.ncbi.nlm.nih.gov/pubmed/27234458">found similar clusters</a> in the DNA of other bacteria (and <a href="https://en.wikipedia.org/wiki/Archaea">archaea</a>). They gave these sequences a name: Clustered Regularly Interspaced Short Palindromic Repeats — or CRISPR.</p>
<p id="uTXTtL">Yet the function of these CRISPR sequences was mostly a mystery until 2007, when food scientists studying the Streptococcus<em> </em>bacteria used to make yogurt <a href="http://science.sciencemag.org/content/315/5819/1709.abstract">showed</a> that these odd clusters actually served a vital function: They’re part of the bacteria’s immune system.</p>
<p id="LHJvYv">See, bacteria are under constant assault from <a href="https://en.wikipedia.org/wiki/Bacteriophage">viruses</a>, so they produce enzymes to fight off viral infections. Whenever a bacterium’s enzymes manage to kill off an invading virus, other little enzymes will come along, scoop up the remains of the virus’s genetic code and cut it into tiny bits. The enzymes then store those fragments in CRISPR spaces in the bacterium’s own genome.</p>
<p id="5xTt4V">Now comes the clever part: CRISPR spaces act as a rogue’s gallery for viruses, and bacteria use the genetic information stored in these spaces to fend off future attacks. When a new viral infection occurs, the bacteria produce special attack enzymes, known as Cas9, that carry around those stored bits of viral genetic code like a mug shot. When these Cas9 enzymes come across a virus, they see if the virus’s RNA matches what’s in the mug shot. If there’s a match, the Cas9 enzyme starts chopping up the virus’s DNA to neutralize the threat. It looks a little like this:</p>
<figure class="e-image">
<img alt=" " data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/NFehN9H-c2CFZa96aJh7swuydqQ=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/7725763/crispr_bg.jpg">
<cite>Shutterstock</cite>
<figcaption>CRISPR/Cas9 gene editing complex from Streptococcus pyogenes. The Cas9 nuclease protein uses a guide RNA sequence to cut DNA at a complementary site. Cas9 protein red, DNA yellow, RNA blue.</figcaption>
</figure>
<p id="8bHouS">So that’s what CRISPR/Cas9 does. For a while, these discoveries weren’t of much interest to anyone except microbiologists — until a series of further breakthroughs occurred.</p>
<h3 id="ttQ2gf">How did CRISPR revolutionize gene editing?</h3>
<p id="JdfXj2">In 2011, Jennifer Doudna of the University of California Berkeley and Emmanuelle Charpentier of Umeå University in Sweden <a href="http://www.nature.com/news/the-quiet-revolutionary-how-the-co-discovery-of-crispr-explosively-changed-emmanuelle-charpentier-s-life-1.19814">were puzzling over</a> how the CRISPR/Cas9 system actually worked. How did the Cas9 enzyme match the RNA in the mug shots with that in the viruses? How did the enzymes know when to start chopping? </p>
<p id="DqY2L2">The scientists soon discovered they could “fool” the Cas9 protein by feeding it artificial RNA — a fake mug shot. When they did that, the enzyme would search for anything<em> </em>with that same code, not just viruses, and start chopping. In a landmark 2012 <a href="http://science.sciencemag.org/content/337/6096/816.abstract">paper</a>, Doudna, Charpentier, and Martin Jinek showed they could use this CRISPR/Cas9 system to cut up any genome at any place they wanted. </p>
<p id="NNmy3G">While the technique had only been demonstrated on molecules in test tubes at that point, the implications were breathtaking.</p>
<p id="FjCYWB">Further advances followed. Feng Zhang, a scientist at the Broad Institute in Boston, <a href="http://science.sciencemag.org/content/339/6121/819.abstract?ijkey=457137443f178c4c6c0c496275700052c568705a&keytype2=tf_ipsecsha">co-authored a paper</a> in <em>Science</em> in February 2013 showing that CRISPR/Cas9 could be used to edit the genomes of cultured mouse cells or human cells. In the same issue of <em>Science</em>, Harvard’s George Church and his team <a href="http://science.sciencemag.org/content/339/6121/823.abstract?ijkey=c4ad594b20c34130d089db0b7b184c5688ac9295&keytype2=tf_ipsecsha">showed</a> how a different CRISPR technique could be used to edit human cells.</p>
<p id="OuNZOP">Since then, researchers have found that CRISPR/Cas9 is amazingly versatile.<strong> </strong>Not only can scientists use CRISPR to “silence” genes by snipping them out, they can also harness repair enzymes to <a href="https://www.addgene.org/crispr/guide/">substitute desired genes</a> into the “hole” left by the snippers (though this latter technique is trickier to pull off). So, for instance, scientists could tell the Cas9 enzyme to snip out a gene that causes Huntington’s disease and insert a “good” gene to replace it.</p>
<figure class="e-image">
<img alt=" " data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/V1wDFk3IDWopKw5ftEFCD9toWYE=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/7724917/Artboard_1.jpg">
<cite>Javier Zarracina/Vox</cite>
</figure>
<p id="tu1sjV">Gene editing itself isn’t new. Various techniques to knock out genes <a href="http://science.sciencemag.org/content/346/6213/1258096.abstract">have been around for years</a>. What makes CRISPR so revolutionary is that it’s so precise: The Cas9 enzyme mostly goes wherever you tell it to. And it’s incredibly cheap and easy: In the past, it might have cost thousands of dollars and weeks or months of fiddling to alter a gene. Now it might cost just $75 and only take a few hours. And this technique has worked on every organism it’s been tried on.</p>
<p id="i9OD9b">It’s now one of the hottest fields around. In 2011, there were fewer than 100 published papers on CRISPR. In 2018, there were <a href="https://scholar.google.com/scholar?as_ylo=2018&q=crispr&hl=en&as_sdt=0,9">more than 17,000</a> and counting, with refinements to CRISPR, new techniques for manipulating genes, improvements in precision, and more. “This has become such a fast-moving field that I even have trouble keeping up now,” says Doudna. “We’re getting to the point where the efficiencies of gene editing are at levels that are clearly going to be useful therapeutically as well as a vast number of other applications.”</p>
<p id="qjlZ1V">There’s also been an intense legal battle over who exactly should get credit for this CRISPR technology and who owns the potentially lucrative rights. Was Doudna’s 2012 paper at the University of California Berkeley the breakthrough, or was Zhang’s 2013 research at the Broad Institute the key advance? In September, a <a href="https://www.mercurynews.com/2018/09/10/uc-berkeley-loses-legal-fight-over-crispr-patents/">federal appeals court</a> rejected the University of California Berkeley’s arguments that the school has exclusive rights to CRISPR patents, upholding the Broad Institute’s patents on some CRISPR applications. </p>
<p id="sBKa3k">But the important thing is that CRISPR has<strong> </strong>arrived.</p>
<h3 id="0M2Wju">So what can we use CRISPR for?</h3>
<figure class="e-image">
<img alt=" " data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/rOzE7wQO7MZT8o1bW4HbAie7yT4=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/7220933/shutterstock_81557950.jpg">
<cite>Shutterstock</cite>
<figcaption>What am I in for now?</figcaption>
</figure>
<p id="9DZJpJ">So. Many. Things. </p>
<p id="beyLTg"><a href="http://www.ipscell.com/">Paul Knoepfler</a>, an associate professor at UC Davis School of Medicine, <a href="http://www.vox.com/2015/5/4/8547797/what-is-crispr">told Vox</a> that CRISPR makes him feel like a “kid in a candy store.” </p>
<p id="Zk0ynm">At the most basic level, CRISPR can make it much easier for researchers to figure out what different genes in different organisms actually <em>do — </em>by, for instance, knocking out individual genes and seeing which traits are affected. This is important: While we’ve had a <a href="https://en.wikipedia.org/wiki/Human_Genome_Project">complete “map” of the human genome</a> since 2003, we don’t really know what function all those genes serve. CRISPR can help speed up genome screening, and genetics research <a href="http://www.nature.com/news/crispr-gene-editing-is-just-the-beginning-1.19510">could advance massively as a result</a>.</p>
<p id="NCtn7j">Researchers have also discovered there are numerous CRISPRs. So CRISPR is actually a pretty broad term. “It’s like the term ‘fruit’ — it describes a whole category,” said the Broad’s Zhang. When people talk about CRISPR, they are usually referring to the CRISPR/Cas9 system we’ve been talking about here. But in recent years, researchers like Zhang have found other types of CRISPR proteins that also work as gene editors. Cas13, for example, can edit DNA’s sister, RNA. “Cas9 and Cas13 are like apples and bananas,” Zhang added. </p>
<p id="9OqRxz">The real fun — and, potentially, the real risks — could come from using CRISPRs to edit various plants and animals. A 2016 paper in <a href="https://www.nature.com/articles/nbt.3659"><em>Nature Biotechnology</em></a><em> </em>by Rodolphe Barrangou and Doudna listed a flurry of potential future applications:</p>
<p id="3l17dE"><strong>1) Edit crops to be more nutritious:</strong> Crop scientists are already looking to use CRISPR to <a href="https://www.fastcoexist.com/3056693/crispr-is-going-to-revolutionize-our-food-system-and-start-a-new-war-over-gmos">edit the genes of various crops</a> to make them tastier or more nutritious or better survivors of heat and stress. They could potentially use CRISPR to snip out the allergens in peanuts. Korean researchers are looking to see if CRISPR could help bananas survive a deadly fungal disease. Some scientists have shown that CRISPR can <a href="http://www.nature.com/nbt/journal/v34/n5/full/nbt.3560.html">create hornless dairy cows</a> — a huge advance for animal welfare. </p>
<p id="pp4RBc">Recently, major companies like <a href="https://www.statnews.com/2016/09/22/monsanto-licenses-crispr/">Monsanto</a> and <a href="http://www.dupont.com/corporate-functions/media-center/press-releases/dupont-and-caribou-biosciences-announce-strategic-alliance.html">DuPont</a> have begun licensing CRISPR technology, hoping to develop valuable new crop varieties. While this technique won’t entirely replace traditional GMO techniques, which can transplant genes from one organism to another, CRISPR is a versatile new tool that can help identify genes associated with desired crop traits much more quickly. It could also allow scientists to insert desired traits into crops more precisely than traditional breeding, which is a much messier way of swapping in genes.</p>
<p id="kokcNg">“With genome editing, we can absolutely do things we couldn’t do before,” says Pamela Ronald, a plant geneticist at the University of California Davis. That said, she cautions that it’s only one of many tools for crop modification out there — and successfully breeding new varieties could still take years of testing. </p>
<p id="IwW1zh">It’s also possible that these new tools could attract controversy. Foods that have had a few genes knocked out via CRISPR <a href="http://www.vox.com/2016/5/18/11690992/gmos-review-evidence-safety-health">are currently regulated more lightly</a> than traditional GMOs. Policymakers in Washington, DC, are currently debating whether it might make sense to rethink regulations here. This piece for Ensia by Maywa Montenegro <a href="http://ensia.com/voices/crispr-is-coming-to-agriculture-with-big-implications-for-food-farmers-consumers-and-nature/">delves into some of the debates</a> CRISPR raises in agriculture.</p>
<p id="vpiEkA"><strong>2) New tools to stop genetic diseases: </strong>Scientists are now using CRISPR/Cas9 to edit the human genome and try to knock out genetic diseases like hypertrophic cardiomyopathy. They’re also looking at using it on mutations that cause Huntington’s disease or cystic fibrosis, and are talking about trying it on the BRCA-1 and 2 mutations linked to breast and ovarian cancers. Scientists have even shown that CRISPR can knock HIV infections <a href="http://www.pnas.org/content/111/31/11461.abstract">out of T cells</a>.</p>
<p id="QltHiA">So far, however, scientists have only tested this on cells in the lab. There are still <a href="http://www.pnas.org/content/112/20/6245.full#ref-20">a few hurdles to overcome</a> before anyone starts clinical trials on actual humans. For example, the Cas9 enzymes <a href="https://www.statnews.com/2016/07/18/crispr-off-target-effects/">can occasionally “misfire”</a> and edit DNA in unexpected places, which in human cells might <a href="https://www.statnews.com/2018/06/11/crispr-hurdle-edited-cells-might-cause-cancer/">lead to cancer</a> or even <a href="https://www.statnews.com/2018/07/16/crispr-potential-dna-damage-underestimated/">create new diseases</a>. As geneticist Allan Bradley, of England’s Wellcome Sanger Institute, <a href="https://www.scientificamerican.com/article/potential-dna-damage-from-crispr-seriously-underestimated-study-finds/">told STAT</a>, CRISPR’s <a href="https://www.nature.com/articles/nbt.4192">ability to wreak havoc on DNA</a> has been “seriously underestimated.” </p>
<p id="EeWleT">And while <a href="https://www.statnews.com/2016/04/20/clever-crispr-advance-unveiled/">there have also been major advances</a> in improving CRISPR precision and reducing these off-target effects, scientists are urging caution on human testing. That’s a big reason why Jiankui’s experiments in producing human babies with CRISPR-edited genomes are so controversial and alarming. Researchers who examined the few findings that Jiankui publicly revealed said the results showed that the babies’ genes were <a href="https://www.theverge.com/2018/11/29/18116830/crispr-baby-he-jiankui-genetics-ethics-science-health-mutation">not edited precisely</a>.<strong> </strong>There’s also plenty of work to be done on actually delivering the editing molecules to particular cells — a major challenge going forward.</p>
<p id="5zp6PN"><strong>3) Powerful new antibiotics and antivirals</strong><strong>:</strong> One of the most frightening public health facts around is that <a href="http://www.vox.com/2016/9/20/12979968/antibiotic-resistance-superbugs-un">we are running low on effective antibiotics</a> as bacteria evolve resistance to them. Currently, it’s difficult and costly to develop fresh antibiotics for deadly infections. But CRISPR/Cas9 systems could, in theory, be developed to eradicate certain bacteria more precisely than ever (though, again, figuring out delivery mechanisms will be a challenge). Other researchers are working on CRISPR systems that target viruses such as HIV and herpes. </p>
<p id="A9i9Fk"><strong>4) Gene drives that could alter entire species: </strong>Scientists have also demonstrated that CRISPR could be used, in theory, to modify not just a single organism but an entire species. It’s an unnerving concept called <a href="http://www.vox.com/2016/6/9/11890472/gene-drive-benefits-risk">“gene drive.”</a></p>
<p id="MCDRtI">It works like this: Normally, whenever an organism like a fruit fly mates, there’s a 50-50 chance that it will pass on any given gene to its offspring. But using CRISPR, scientists can alter these odds so that there’s a nearly 100 percent chance that a particular gene gets passed on. Using this gene drive, scientists could ensure that an altered gene propagates throughout an entire population in short order:</p>
<figure class="e-image">
<img alt=" " data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/r_-jyTW7r3heg08vJKL08GnVGHo=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/7724927/Artboard_3.jpg">
<cite>Javier Zarracina; <a class="ql-link" href="http://rifters.com/real/articles/Science-2014-Oye-626-8.pdf" target="_blank">Oye et al. 2014</a></cite>
</figure>
<p id="4Hw4Eu">By harnessing this technique, scientists could, say, genetically modify mosquitoes to only produce male offspring — and then use a gene drive to push that trait through an entire population. Over time, the population would go extinct. “Or you could just add a gene making them resistant to the malaria parasite, preventing its transmission to humans,” Vox’s Dylan Matthews explains in his story on <a href="https://www.vox.com/science-and-health/2018/5/31/17344406/crispr-mosquito-malaria-gene-drive-editing-target-africa-regulation-gmo">CRISPR gene drives for malaria</a>. </p>
<p id="7AVhnc">Suffice to say, there are also hurdles to overcome before this technology is rolled out en masse — and not necessarily the ones you’d expect. “The problem of malaria gene drives is rapidly becoming a problem of politics and governance more than it is a problem of biology,” Matthews writes. Regulators will need to figure out how to handle this technology, and ethicists will need to grapple with knotty questions about its fairness. </p>
<p id="4alFnd"><strong>5) Creating </strong><strong>“</strong><strong>designer babies</strong><strong>”:</strong><strong> </strong>This is the one that gets the most attention, and rightly so. It’s not entirely far-fetched to think we might one day be confident enough in CRISPR’s safe to use it to edit the human genome — to eliminate disease, or to select for athleticism or superior intelligence. </p>
<p id="Dd9ioG">But <a href="https://www.theatlantic.com/science/archive/2018/11/china-crispr-babies/576784/">Jiankui’s recent attempt to introduce protection from HIV</a> in embryos intended for pregnancy, which involved little oversight, is not how most scientists want the field to move forward.</p>
<p id="ZQDkW4">The concern is that there are not enough safeguards yet to prevent harm nor enough knowledge to do definite good. In Jiankui’s case, he also did not tell his university about his experiment ahead of time, likely did not fully inform the parents of the modified babies of the risks involved, and may have had a financial incentive from his two affiliated biotech companies. </p>
<p id="ufIECQ">We’re not even close to the point where scientists could safely make the complex changes needed to, for instance, improve intelligence, in part because it involves so many genes. So don’t go dreaming of <a href="https://en.wikipedia.org/wiki/Gattaca">Gattaca</a> just yet.</p>
<p id="zMs2mR">“I think the reality is we don’t understand enough yet about the human genome, how genes interact, which genes give rise to certain traits, in most cases, to enable editing for enhancement today,” Doudna said<a href="http://www.vox.com/2015/12/3/9845230/crispr-gene-editing-caution"> in 2015</a>. Still, she added: “That’ll change over time.”</p>
<h3 id="kxHFiX">Wait, should we really create designer babies?</h3>
<figure class="e-image">
<img alt=" " data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/Y8d4D7UVpVgDlIwR5lQP5LCWeoE=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/7220099/shutterstock_299699342.jpg">
<cite>(Shutterstock)</cite>
<figcaption>Can’t wait to have a superhuman sister.</figcaption>
</figure>
<p id="CJU5Jy">Given all the fraught issues associated with gene editing, many scientists are advocating a slow approach here. They are also trying to keep the conversation about this technology open and transparent, build public trust, and <a href="https://www.vox.com/science-and-health/2018/7/18/17586198/crispr-food-agriculture-national-academies-science-gmos">avoid some of the mistakes that were made with GMOs</a>. But with CRISPR’s ease of use and low costs, it’s challenging to keep rogue experiments in check. </p>
<p id="kOicUN">In February 2017, a <a href="http://www8.nationalacademies.org/onpinews/newsitem.aspx?RecordID=24623">report</a> from the National Academy of Sciences said that clinical trials could be greenlit in the future “for serious conditions under stringent oversight.” But it also made clear that “genome editing for enhancement should not be allowed at this time.”</p>
<p id="uUcvqu">Society still needs to grapple with all the ethical considerations at play here. For example, if we edited a germline, future generations wouldn’t be able to opt out. Genetic changes might be difficult to undo. Even this stance has worried some researchers, like <a href="http://www.nih.gov/about/director/04292015_statement_gene_editing_technologies.htm">Francis Collins</a> of the National Institutes of Health, who has said the US government will not fund any genomic editing of human embryos.</p>
<p id="Y8WvYM">In the meantime, researchers in the US who can drum up their own funding, along with others in the UK, Sweden, and China, <a href="http://www.nature.com/news/gene-editing-research-in-human-embryos-gains-momentum-1.19767">are moving forward</a> with their own experiments. </p>
<h3 id="uw4Btw">Further reading</h3>
<ul>
<li id="XifgSr">Julia Belluz discussed the implications <a href="https://www.vox.com/science-and-health/2018/11/30/18119589/crispr-technology-he-jiankui">He Jiankui</a>’s startling announcement of human babies with edited genomes and the prospects <a href="https://www.vox.com/science-and-health/2018/12/6/18126338/crispr-babies-china-gene-editing">CRISPR clinics</a> in the US.</li>
<li id="u3v3cJ">We also reported on <a href="https://www.vox.com/2017/10/25/16527370/crispr-gene-editing-harvard-mit-broad">two CRISPR tools that overcome the scariest parts of gene editing</a>. </li>
<li id="tyKrct">Ezra Klein <a href="https://art19.com/shows/the-ezra-klein-show/episodes/e1c07fbc-b8dc-4378-9edc-d6699cddf00e">interviewed</a> UC Berkeley’s Jennifer Doudna, one of the leading CRISPR researchers, on his podcast in October.</li>
<li id="F3DxEn">Michael Specter’s <a href="https://go.redirectingat.com/?id=66960X1516588&xs=1&url=https%3A%2F%2Fwww.newyorker.com%2Fmagazine%2F2017%2F01%2F02%2Frewriting-the-code-of-life">“Rewriting the Code of Life”</a> in the New Yorker.</li>
<li id="BxBI0w">Carl Zimmer has been on the CRISPR beat for a long time. His 2015 piece in Quanta is <a href="https://www.quantamagazine.org/20150206-crispr-dna-editor-bacteria/">well worth reading</a>.</li>
<li id="wXiRR9">Sharon Begley has also been on the CRISPR beat, and <a href="https://www.scientificamerican.com/article/potential-dna-damage-from-crispr-seriously-underestimated-study-finds/">recently unpacked</a> the <a href="https://www.statnews.com/2018/06/15/crispr-cancer-questions-answered/">latest studies</a> on potential harms of gene editing. </li>
<li id="vyXmqc">In 2016, <em>Nature </em><a href="http://www.nature.com/news/beyond-crispr-a-guide-to-the-many-other-ways-to-edit-a-genome-1.20388">explored</a> some of the subtle limitations of CRISPR — and the search for additional gene-editing tools. And <a href="http://www.nature.com/news/crispr-gene-editing-is-just-the-beginning-1.19510">this earlier <em>Nature </em>piece</a> by Heidi Ledford is a delightfully wonky dive into the ways researchers could use CRISPR to explore the genome. It’s also worth <a href="http://www.nature.com/nbt/journal/v34/n9/full/nbt.3659.html">checking out this paper</a> listing all the future applications of CRISPR.</li>
</ul>
https://www.vox.com/2018/7/23/17594864/crispr-cas9-gene-editingBrad PlumerEliza BarclayJulia BelluzUmair Irfan2018-12-11T17:23:01-05:002018-12-11T17:23:01-05:00Why Trump wants to repeal an Obama-era clean water rule
<figure>
<img alt="Rising Sea Levels Threatens Coast Of Maryland’s Hoopers Island" src="https://cdn.vox-cdn.com/thumbor/bmFA9ZyAQz6N_WmG0q5fMjl2XmM=/288x0:4896x3456/1310x983/cdn.vox-cdn.com/uploads/chorus_image/image/53465617/456945284.0.jpg" />
<figcaption>Birds occupy a dilapidated pier on the Little Blackwater River October 9, 2014, in Church Creek, Maryland. | Mark Wilson/Getty Images</figcaption>
</figure>
<p>The EPA this week revealed a plan to determine which waterways are protected by the federal government.</p> <p id="NrKY4x">On Tuesday, the Environmental Protection Agency and the US Army Corps of Engineers presented the Trump administration’s proposal to undo a major Obama-era environmental regulation, the <a href="https://www.epa.gov/cleanwaterrule">Clean Water Rule</a>. </p>
<p id="upy3Tj">The rule defined the “Waters of the United States,” a.k.a. <a href="https://www.epa.gov/newsreleases/epa-and-army-propose-new-waters-united-states-definition">WOTUS</a>. These are the rivers, streams, and lakes that fall under federal jurisdiction and forms the foundation of a massive piece of environmental regulation, the <a href="https://www.epa.gov/laws-regulations/summary-clean-water-act">Clean Water Act</a>. </p>
<p id="RmBasf">The Obama rule, first published in 2015, was meant to clarify which streams and wetlands fall under federal clean water protections — a question that had been causing legal frustration for years.</p>
<p id="KfuEtk">But it triggered fierce blowback from farm and industry groups across the country. “Opponents condemn it as a massive power grab by Washington,” Politico <a href="http://www.politico.com/story/2015/05/epa-waterways-wetlands-rule-118319">reported</a>, “saying it will give bureaucrats carte blanche to swoop in and penalize landowners every time a cow walks through a ditch.” Some of those criticisms were overblown (it doesn’t cover <a href="https://www.epa.gov/sites/production/files/2015-06/documents/cwr_response_to_comments_17_non_technical_comments_vol2.pdf">puddles</a>, for instance), but the rule was widely cited by conservatives as a perfect example of EPA overreach under President Obama. </p>
<p id="0y7ybe">Last year, President Trump <a href="https://twitter.com/jonathanvswan/status/836529019893997568">signed an executive order</a> directing the EPA to begin the long process of repealing the Clean Water Rule and replacing it with ... something else.</p>
<p id="iB839O">Earlier this year, the EPA suspended the Obama rule. And on Tuesday, the agency revealed its replacement, one it said will smooth over the problems that made the 2015 regulation so contentious.</p>
<p id="fgljLC">“For the first time, we are clearly defining the difference between federally protected waterways and state protected waterways,” said EPA acting Administrator Andrew Wheeler in a press release. “Our simpler and clearer definition would help landowners understand whether a project on their property will require a federal permit or not, without spending thousands of dollars on engineering and legal professionals.” </p>
<div id="XH7SEN">
<blockquote class="twitter-tweet">
<p lang="en" dir="ltr">.<a href="https://twitter.com/EPAAWheeler?ref_src=twsrc%5Etfw">@EPAAWheeler</a> and Army Asst Secretary for Civil Works RD James sign the proposed new definition of <a href="https://twitter.com/hashtag/WOTUS?src=hash&ref_src=twsrc%5Etfw">#WOTUS</a> surrounded by <a href="https://twitter.com/SecretaryZinke?ref_src=twsrc%5Etfw">@SecretaryZinke</a> and Congressional leaders <a href="https://t.co/W2P8V4w1RD">pic.twitter.com/W2P8V4w1RD</a></p>— Molly Block (@mollyerinb) <a href="https://twitter.com/mollyerinb/status/1072530260414160897?ref_src=twsrc%5Etfw">December 11, 2018</a>
</blockquote>
<script async="" src="https://platform.twitter.com/widgets.js" charset="utf-8"></script>
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<p id="UGXe9k">However, environmental groups said the new definition would cut the number of waterways the federal government must regulate, leaving them vulnerable to pollution. It excludes, for example, waterways that flow only for parts of the year, like after rainstorms while snow melts.</p>
<p id="M2QYUY">“This sickening gift to polluters will result in more dangerous toxic pollution dumped into waterways across a vast stretch of America,” said Brett Hartl, government affairs director at the Center for Biological Diversity, in a statement. “The Trump administration’s radical proposal would destroy millions of acres of wetlands, pushing imperiled species like steelhead trout closer to extinction.”</p>
<p id="AAj87z">EPA officials said they didn’t know just how many waterways would be excluded from federal jurisdiction under the new proposal. However, a document obtained by <a href="https://www.eenews.net/stories/1060109323">E&E News</a> showed that the EPA and the Army Corps had estimated last year that 18 percent of streams and 51 percent of wetlands would not receive federal protections under the revisions. </p>
<p id="iHvvos">Tuesday’s announcement is only the beginning of a long regulatory and legal process. The EPA is taking comments on the proposal for 60 days and will host a listening session in Kansas City, Kansas, in January. In the meantime, it’s worth understanding how WOTUS became so controversial and what it means for huge swaths of the country. Here’s what you need to know. </p>
<h3 id="BDYMil">What the Waters of the US rule actually does</h3>
<figure class="e-image">
<img alt=" " data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/2a6-6aYUARCSvchRcQJiKwKg7aU=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/8069445/shutterstock_585463217.jpg">
<cite>Shutterstock</cite>
<figcaption>Caught between a rock and a tributary place.</figcaption>
</figure>
<p id="YX40gA">To understand this rule, we need to go back to 1972, when Congress passed the <a href="https://en.wikipedia.org/wiki/Clean_Water_Act">Clean Water Act</a>. That law features dozens of regulations and permitting requirements for anyone discharging pollution into the “waters of the United States” in a way that could affect human health or aquatic life. These rules apply to factories, power plants, golf courses, new housing developments — and much, much more.</p>
<p id="8QqhL7">For example, under the law, a facility storing oil that could leak needs to prepare a spill prevention plan aimed at minimizing discharges. If the facility is far away from any “waters of the United States,” however, it doesn’t face these requirements. </p>
<p id="FLj5Ef">But here’s the tricky part. The Clean Water Act doesn’t precisely define what “waters of the United States” means. That’s left to the EPA and the Army Corps of Engineers. And it’s a hard question. For instance, the law is clear that major navigable rivers and lakes and any connected waterways should be protected. That includes major rivers like the Mississippi River, the Colorado River, and the Ohio River. But what about waterways that are only <em>loosely</em> connected? What about the 60 percent of streams that are dry for part of the year but then connect when it rains? Any pollution dumped into those waters could affect key ecosystems. Should they be regulated?</p>
<p id="XGJMwV">In the 2000s, this uncertainty led to a pair of Supreme Court decisions that only ended up creating more bewilderment. In a split decision in <a href="https://en.wikipedia.org/wiki/Rapanos_v._United_States"><em>Rapanos v. United States</em></a><em> </em>in 2006, Justice Anthony Kennedy argued that Clean Water Act protections applied to wetlands that “significantly affect the chemical, physical, and biological integrity of other covered waters.” But Justice Antonin Scalia argued that protections only applied to wetlands “with a continuous surface connection” to navigable water — a far smaller number of wetlands. And it wasn’t totally clear which opinion took precedence.</p>
<figure class="e-image">
<img alt="Supreme Court Justice Antonin Scalia Gives Speech In Philadelphia" data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/GnVPvYcriDH9vEQpRYSZd4igD64=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/8061235/50784382.jpg">
<cite>William Thomas Cain/Getty Images</cite>
<figcaption>What’d I do?</figcaption>
</figure>
<p id="21GLh4">"The short answer is that the state of post-<em>Rapanos</em> wetlands jurisdiction is a mess," Richard Frank of the University of California Davis <a href="http://www.nytimes.com/gwire/2011/02/07/07greenwire-supreme-courts-murky-clean-water-act-ruling-cr-33055.html">told</a> Greenwire in 2011. In the ensuing years, whenever a dispute arose over whether a landowner — be it a housing developer, a golf course, a farm, or what have you — needed a Clean Water Act permit or not, courts had to resolve it on a case-by-case basis.</p>
<p id="QFlyRk">So under Obama, the EPA and Army Corps of Engineers tried to bring clarity to the matter. They sifted through more than 1,200 scientific papers to figure out which types of bodies of water were important to aquatic ecosystems and therefore deserved protection, per Kennedy’s opinion. </p>
<p id="d045qK">The final <a href="https://www.epa.gov/sites/production/files/2015-06/documents/epa-hq-ow-2011-0880-20862.pdf">Waters of the US rule</a>, published in June 2015, outlined which bodies of water were automatically covered by the Clean Water Act — requiring permits for discharges or dredging or dirt fill — and which ones still needed to be dealt with on a case-by-case basis. <a href="https://www.epa.gov/sites/production/files/2015-05/documents/fact_sheet_summary_final_1.pdf">For instance</a>:</p>
<ul>
<li id="OMM71Y">In the past, tributaries of navigable rivers were evaluated on a case-by-case basis. But under the new rule, they’re automatically protected if they have a bed, a bank, and a high-water mark. This includes many streams that are dry for part of the year. Waterways without these features are still dealt with case by case.</li>
<li id="uprAUY">Wetlands and ponds are now automatically covered if they’re within 100 feet or within the 100-year floodplain of a protected waterway. Otherwise, it’s case by case.</li>
<li id="ObShYN">Certain “isolated” waters that are not connected to navigable waters now get automatic protection if they have a “significant nexus” to protected waters — like the <a href="https://www.wildlife.ca.gov/Conservation/Plants/Vernal-Pools">vernal pools of California</a>.</li>
</ul>
<p id="qAk8QH">The rule also explicitly exempted a number of bodies of water often found on farms, such as puddles, ditches, artificial ponds for livestock watering, and irrigation systems that would revert to dry land if irrigation were to stop. Here’s a graphic: </p>
<figure class="e-image">
<img alt=" " data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/3bUVhLu6JFZxUD1Hoef2ScRreZc=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/8061149/Screen_Shot_2017_02_28_at_11.42.48_AM.png">
<cite>(EPA)</cite>
</figure>
<p id="rmeDLD">For its part, the EPA argued that this rule didn’t significantly expand the waters under its jurisdiction. Rather, it created more certainty <a href="https://www.epa.gov/sites/production/files/2014-09/documents/q_a_wotus.pdf">for about 3 percent</a> of the nation’s waterways — to avoid bringing cases to court every time there was a legal gray area. According to the EPA, the rule offered clearer protection to upstream bodies of water that contribute to drinking supplies for one-third of the population. </p>
<p id="aiUrMt">Before the rule came out, few who worked on it expected widespread blowback. “This rule will provide the clarity and certainty businesses and industry need about which waters are protected by the Clean Water Act,” Obama said when the final rule was announced. But things turned out very differently.</p>
<h3 id="qlL1Ul">Why the Waters of the US rule became so controversial</h3>
<p id="EQs8XL">Opponents of the rule — particularly farming and ranching groups — clearly didn’t buy the EPA’s line that this was only a technical update. Nor were they comforted by the EPA’s exemptions for agriculture. Instead, they called it a power grab.</p>
<p id="OG6WHw">“The agency is making it impossible for farmers and ranchers to look at their land and know what can be regulated,” <a href="http://www.fb.org/issues/regulatory-reform/clean-water-act/">argues</a> the American Farm Bureau Federation on its site. “EPA has vastly expanded its authority beyond the limits approved by Congress and affirmed by the U.S. Supreme Court.”</p>
<p id="UGvf7e">Some Western farmers, for instance, fretted about the open, unlined canals they use to irrigate their lands during the growing season. These systems divert water from streams, serve as water sources for wildlife, and can connect to larger bodies of water elsewhere. As Reagan Waskom and David Cooper of Colorado State University <a href="https://theconversation.com/why-farmers-and-ranchers-think-the-epa-clean-water-rule-goes-too-far-72787?utm_medium=Social&utm_campaign=Echobox&utm_source=Twitter&utm_term=Autofeed#link_time=1488265585">explain</a>, farmers and ranchers feared that these canals would fall under the rule’s definition of “tributary” and might have to be replaced by costly pressurized pipes. Or, alternatively, that fertilizer use near these waterways would be more strictly regulated.</p>
<figure class="e-image">
<img alt="California’s Dams And Reservoirs Depleted By Extreme Drought" data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/fZI6_fob5-WUkyhSDroOUXYHIeE=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/8061577/453350414.jpg">
<cite>Justin Sullivan/Getty Images</cite>
<figcaption>Water stands in an irrigation canal at a sod farm on August 8, 2014, in Lodi, California.</figcaption>
</figure>
<p id="vJ35W0">Defenders of the rule dismissed these scenarios. Jon Devine, a lawyer with the Natural Resources Defense Council, pointed out that the Clean Water Act has always regulated agriculture lightly. “This rule doesn’t really change those exemptions,” he says. Indeed, one <a href="https://elr.info/news-analysis/46/10743/%E2%80%9Cwaters-united-states%E2%80%9D-and-agricultural-production-sector-sweeping-change-or-more-same">recent study</a> found that the EPA’s jurisdiction over farms actually shrank under the new rule.</p>
<p id="hw1BUe">The EPA was also pretty explicit that it wouldn’t target farmers. “We will protect clean water without getting in the way of farming and ranching,” then-EPA Administrator Gina McCarthy <a href="https://www.epa.gov/speeches/administrator-gina-mccarthy-remarks-national-farmers-union-prepared">told</a> the National Farmers Union in 2015. But few farmers or ranchers believed her. Their argument was that the rule was vague enough that the EPA could<em> </em>crack down on them if it chose. It’s basically a question of trust. And at the moment, conservatives are not particularly inclined to trust the EPA.</p>
<p id="e6yWLd">Joni Ernst, a Republican senator from Iowa, made that clear in former EPA Administrator Scott Pruitt’s confirmation hearing in 2017. “My constituents tell me the EPA is out to get them rather than work with them and there is a huge lack of trust between many of my constituents and the EPA,” she <a href="http://www.ernst.senate.gov/public/index.cfm/2017/1/ernst-questions-pruitt-over-rfs-at-confirmation-hearing">said</a>. “If we take a look specifically at the WOTUS rule, Iowans truly feel that the EPA ignored their comments and concerns, threw them under the rug and then just moved forward.”</p>
<p id="ZXHm6G">However the backlash started, it took on a life of its own. Trump began citing the water rule on the campaign trail as an example of EPA overreach, earning cheers from rural audiences. In signing his executive order in March, he called it a “destructive and horrible rule.”</p>
<h3 id="M5JwOW">Why it will be difficult — but not impossible — for the EPA to undo the Obama-era WOTUS rule completely</h3>
<figure class="e-image">
<img alt="Scott Pruitt Addresses Employees At EPA Headquarters" data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/ZhRLcG4JyoFtDXpVBCamLeWCCCU=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/8069467/643463876.jpg">
<cite>Aaron P. Bernstein/Getty Images</cite>
<figcaption>Former EPA Administrator Scott Pruitt couldn’t unto the Clean Water Rule on his own, but he could put it on hold. </figcaption>
</figure>
<p id="nrzjob">Pruitt delayed the Obama WOTUS rule’s implementation for <a href="https://www.vox.com/energy-and-environment/2018/1/26/16936104/epa-trump-toxic-air-pollution">two years</a>, buying the EPA time to come up with an alternative. </p>
<p id="X521UI">But implementing a new definition for WOTUS requires proposing a new rule that’s supported by extensive scientific and legal arguments, opening up the proposal for public comments, responding to those comments, and then defending the final rule in court as a superior approach. This could take years.</p>
<p id="5J6Omw">And much of the ambiguity around which waterways deserve Clean Water Act protection still holds even if you repeal the Obama rule. Which wetlands are covered? How do you deal with streams that flow part of the year? How do you interpret that mess of a Supreme Court decision in 2006?</p>
<p id="Q1F3gA">In his executive order, Trump asked the EPA to consider Scalia’s opinion in <em>Rapanos</em>, which extended protection to wetlands only if they had a “continuous surface connection" to navigable waterways and extended protection to streams only if they were “relatively permanent.” So it’s not surprising that acting EPA Administrator Wheeler’s replacement rule would cover far fewer waterways — leaving out, for instance, many of the 60 percent of streams that don’t flow year-round.</p>
<p id="NzTUTO">Environmental groups say that’s a problem. Devine argues that polluters could take advantage of a weaker rule with less certain protection for streams and waterways. As long as there’s ambiguity about where the Clean Water Act applies, it would be harder for citizen groups or the Department of Justice to bring a case against companies dumping chemicals or other pollutants into smaller bodies of water upstream. </p>
<p id="KhBftA">“Without this rule, enforcement has been unpredictable,” Devine says. “The EPA has mainly been focused on big rivers and lakes so that they wouldn’t have to litigate to the ends of the earth about whether the Clean Water Act applied to waters upstream. But if you can only regulate the biggest rivers and lakes — and the pollution problem is much farther upstream — then you’re not effectively protecting the receiving water or the watershed.”</p>
<p id="YSQYZy">Still, it’s not clear that the EPA <em>can </em>scale back the water rule significantly. Federal courts have typically embraced Kennedy’s more expansive interpretation of the Clean Water Act rather than Scalia’s, and any rollback of Obama’s rule would still leave plenty of legal gray areas where the courts will need to decide on a case-by-case basis whether the Clean Water Act applies. “It’s going to be incredibly complex to figure this out,” says Richard Revesz, a professor of environmental law at New York University. </p>
<h3 id="KX8slS">Further reading:</h3>
<ul>
<li id="HXJhHD">Repealing the clean water rule is only step one for Trump. He’s also targeting Obama’s signature climate policy, the Clean Power Plan. Read <a href="https://www.vox.com/energy-and-environment/2017/10/10/16443246/gop-climate-health-care">here for more</a> on how he might do that.</li>
<li id="srY395">The EPA is also rolling back restrictions on <a href="https://www.vox.com/energy-and-environment/2018/1/26/16936104/epa-trump-toxic-air-pollution">major sources</a> of toxic air pollution. </li>
</ul>
https://www.vox.com/energy-and-environment/2017/2/28/14761236/wotus-waters-united-states-rule-trumpBrad PlumerUmair Irfan2017-12-22T12:42:57-05:002017-12-22T12:42:57-05:00A simple guide to CRISPR, one of the biggest science stories of the decade
<figure>
<img alt="" src="https://cdn.vox-cdn.com/thumbor/lc_IO-dvWCSBkY1GY08mcDRdI7c=/0x0:2400x1800/1310x983/cdn.vox-cdn.com/uploads/chorus_image/image/52526699/CRISPR_LEAD.0.jpeg" />
<figcaption>The scissors are, of course, metaphorical. | Javier Zarracina</figcaption>
</figure>
<p id="XJ4GLX">One of the biggest and most important science stories of the <em>last</em> few years will probably also be one of the biggest science stories of the <em>next</em> few years. So this is as good a time as any to get acquainted with the powerful new gene-editing technology known as CRISPR.</p>
<p id="Gd6aa1">If you haven’t heard of <a href="https://en.wikipedia.org/wiki/CRISPR">CRISPR</a> yet, the short explanation goes like this: In the past six years, scientists have figured out how to exploit a quirk in the immune systems of bacteria to edit genes in other<em> </em>organisms — plant genes, mouse genes, even<strong> </strong>human genes. With CRISPR, they can now make these edits quickly and cheaply, in days rather than weeks or months. (The technology is often known as CRISPR/Cas9, but we’ll stick with CRISPR, pronounced “crisper.”)</p>
<p id="abSEr5">Let that sink in. We’re talking about a powerful new tool to control what genes get expressed in plants, animals, and even humans. The ability to delete undesirable traits and, potentially, add desirable traits with more precision than ever before. </p>
<p id="jt1jg7">In 2017 alone, researchers <a href="https://www.vox.com/science-and-health/2017/8/2/16083300/crispr-heart-disease">reported</a> in <em>Nature </em>that they’d successfully used CRISPR in human embryos to fix a mutation that causes a terrible heart muscle disorder called hypertrophic cardiomyopathy. (Other researchers <a href="http://www.nature.com/news/doubts-raised-about-crispr-gene-editing-study-in-human-embryos-1.22547">have since called</a> some of the conclusions into question.) Another team used it to <a href="https://www.nature.com/articles/nature25164">reduce the severity of genetic deafness</a> in mice, suggesting it could one day be used to treat the same type of hearing loss in people.</p>
<p id="JrsgqY">In October, <a href="https://www.vox.com/2017/10/25/16527370/crispr-gene-editing-harvard-mit-broad">researchers at the Broad Institute of MIT and Harvard</a> launched a coordinated blitz with two big studies that move CRISPR in that safer and more precise direction. A paper published in <a href="http://science.sciencemag.org/lookup/doi/10.1126/science.aaq0180"><em>Science</em></a><em> </em>describes an entirely new CRISPR-based gene editing tool that targets RNA, DNA’s sister, allowing for transient changes to genetic material. In <a href="http://nature.com/articles/doi:10.1038/nature24644"><em>Nature</em></a>, scientists published on a more refined type of CRISPR gene editing that can alter a single bit of DNA without cutting it — increasing the tool’s precision and efficiency. </p>
<p id="P15AbT">And these are just some of the astounding things researchers have recently shown CRISPR can do. In 2016, we learned that it can help us create <a href="http://www.npr.org/sections/thesalt/2016/04/15/474358416/will-genetically-edited-food-be-regulated-the-case-of-the-mushroom">mushrooms that don’t brown easily</a> and edit bone marrow cells in mice to <a href="https://www.wired.com/2016/11/blood-diseases-show-crisprs-potential-therapy/">treat sickle-cell anemia</a>. Down the road, CRISPR might help us develop drought-tolerant crops and create powerful new antibiotics. CRISPR might one day even allow us to <a href="http://www.vox.com/2016/6/9/11890472/gene-drive-benefits-risk">wipe out entire populations of malaria-spreading mosquitoes</a> or <a href="http://www.sciencemag.org/news/2016/09/should-we-bring-extinct-species-back-dead">resurrect once-extinct species</a> like the passenger pigeon. And, while there are real limits to what CRISPR can do, researchers are working to overcome them.</p>
<p id="fu9G1u">Much of the hype around CRISPR has focused on whether we might <a href="http://www.vox.com/2015/12/3/9845230/crispr-gene-editing-caution">engineer humans with specific genetic traits</a> (like heightened intelligence). But in some ways, that’s a sideshow. “Designer babies” are still far off, and there are enormous obstacles to making those sorts of complex genetic modifications. The stuff that’s closer at hand — from new therapies to revolutions in our understanding of the genome — is what’s most exciting. So here’s a basic guide to what CRISPR is and what it can do.</p>
<h3 id="5KYunY">What the heck is CRISPR, anyway?</h3>
<div id="cTf0ki"><div><div style="left: 0px; width: 100%; height: 0px; position: relative; padding-bottom: 56.2493%;"><iframe src="https://www.youtube.com/embed/2pp17E4E-O8?wmode=transparent&rel=0&autohide=1&showinfo=0&enablejsapi=1" frameborder="0" allowfullscreen="" style="top: 0px; left: 0px; width: 100%; height: 100%; position: absolute;"></iframe></div></div></div>
<p id="iSNPTs">If we want to understand CRISPR, we should go back to 1987, when Japanese scientists studying <em>E. coli </em>first came across some unusual repeating sequences in the bacteria’s DNA. “The biological significance of these sequences,” <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC213968/pdf/jbacter00202-0107.pdf">they wrote</a>, “is unknown.” Over time, other researchers <a href="https://www.ncbi.nlm.nih.gov/pubmed/27234458">found similar clusters</a> in the DNA of other bacteria (and <a href="https://en.wikipedia.org/wiki/Archaea">archaea</a>). They gave these sequences a name: Clustered Regularly Interspaced Short Palindromic Repeats — or CRISPR.</p>
<p id="uTXTtL">Yet these CRISPR sequences were mostly a mystery until 2007, when food scientists studying the <em>Streptococcus </em>bacteria used to make yogurt <a href="http://science.sciencemag.org/content/315/5819/1709.abstract">showed</a> how these odd clusters actually served a vital function: They’re part of the bacteria’s immune system.</p>
<p id="LHJvYv">See, bacteria are under constant assault from <a href="https://en.wikipedia.org/wiki/Bacteriophage">viruses</a> and produce enzymes to fight off viral infections. Whenever the bacteria’s enzymes manage to kill off an invading virus, other little enzymes will come along, scoop up the remains of the virus’s genetic code, cut it up into little bits, and then store it in those CRISPR spaces.</p>
<p id="5xTt4V">Now comes the clever part: The bacteria uses the genetic information stored in these CRISPR spaces to fend off <em>future</em> attacks. When a new infection occurs, the bacteria produces special attack enzymes — known as Cas9 — that carry around those stored bits of viral genetic code like a mugshot. When these Cas9 enzymes come across a virus, they see if the virus’s RNA matches what’s in the mugshot. If there’s a match, the Cas9 enzyme starts chopping the virus’s DNA up and neutralizing the threat. It looks a little like this:</p>
<figure class="e-image">
<img alt=" " data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/NFehN9H-c2CFZa96aJh7swuydqQ=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/7725763/crispr_bg.jpg">
<cite>Shutterstock</cite>
<figcaption>CRISPR/Cas9 gene editing complex from Streptococcus pyogenes. The Cas9 nuclease protein uses a guide RNA sequence to cut DNA at a complementary site. Cas9 protein: red. DNA yellow, RNA blue.</figcaption>
</figure>
<p id="QsUg9T">So that’s what CRISPR/Cas9 does. For a while, these discoveries weren’t of much interest to anyone except microbiologists — until a series of further breakthroughs occurred.</p>
<h3 id="ttQ2gf">How did CRISPR revolutionize gene editing?</h3>
<p id="JdfXj2">In 2011, Jennifer Doudna of the University of California Berkeley and Emmanuelle Charpentier of Umeå University in Sweden <a href="http://www.nature.com/news/the-quiet-revolutionary-how-the-co-discovery-of-crispr-explosively-changed-emmanuelle-charpentier-s-life-1.19814">were puzzling over</a> how the CRISPR/Cas9 system actually worked. How did the Cas9 enzyme match the RNA in the mugshots with that in the viruses? How did the enzymes know when to start chopping? </p>
<p id="DqY2L2">The scientists soon discovered they could “fool” the Cas9 protein by feeding it artificial RNA — a fake mugshot. When they did that, the enzyme would search for <em>anything</em><em> </em>with that same code, not just viruses, and start chopping. In a landmark 2012 <a href="http://science.sciencemag.org/content/337/6096/816.abstract">paper</a>, Doudna, Charpentier and Martin Jinek showed they could use this CRISPR/Cas9 system to cut up <em>any</em> genome at any place they wanted. </p>
<p id="NNmy3G">While the technique had only been demonstrated on molecules in test tubes at that point, the implications were breathtaking.</p>
<p id="FjCYWB">Further advances followed. Feng Zhang, a scientist at the Broad Institute in Boston, <a href="http://science.sciencemag.org/content/339/6121/819.abstract?ijkey=457137443f178c4c6c0c496275700052c568705a&keytype2=tf_ipsecsha">co-authored a paper</a> in <em>Science</em> in February 2013 showing that CRISPR/Cas9 could be used to edit the genomes of cultured mouse cells or human cells. In the same issue of <em>Science</em>, Harvard’s George Church and his team <a href="http://science.sciencemag.org/content/339/6121/823.abstract?ijkey=c4ad594b20c34130d089db0b7b184c5688ac9295&keytype2=tf_ipsecsha">showed</a> how a different CRISPR technique could be used to edit human cells.</p>
<p id="OuNZOP">Since then, researchers have found that CRISPR/Cas9 is ridiculously versatile.<strong> </strong>Not only can scientists use CRISPR to “silence” genes by snipping them out — they can also harness repair enzymes to <a href="https://www.addgene.org/crispr/guide/">substitute in desired genes</a> into the “hole” left by the snippers (though this latter technique is trickier to pull off). So, for instance, scientists could tell the Cas9 enzyme to go snip out a gene that causes Huntington’s disease and insert a “good” gene to replace it.</p>
<figure class="e-image">
<img alt=" " data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/V1wDFk3IDWopKw5ftEFCD9toWYE=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/7724917/Artboard_1.jpg">
<cite>Javier Zarracina/Vox</cite>
</figure>
<p id="CUDp4U">Gene editing itself isn’t new. Various techniques to knock out genes <a href="http://science.sciencemag.org/content/346/6213/1258096.abstract">have been around for years</a>. What makes CRISPR so revolutionary is that it’s incredibly precise: The Cas9 enzyme mostly goes wherever you tell it to go. And it’s incredibly cheap and easy: In the past, it might have cost thousands of dollars and weeks or months of fiddling to alter a gene. Now it might cost just $75 and only take a few hours. And this technique has worked on every organism it’s been tried on.</p>
<p id="i9OD9b">This has become one of the hottest fields around. In 2011, there were fewer than 100 published papers on CRISPR. In 2017, there were <a href="http://www.nature.com/nbt/journal/v34/n9/full/nbt.3659.html">more than 14,000 and counting</a>, with new refinements to CRISPR, new techniques for manipulating genes, improvements in precision, and more. “This has become such a fast-moving field that I even have trouble keeping up now,” says Doudna. “We’re getting to the point where the efficiencies of gene editing are at levels that are clearly going to be useful therapeutically as well as a vast number of other applications.”</p>
<p id="qjlZ1V">There’s been intense legal battle over who, exactly, should get credit for this CRISPR technology — was Doudna’s 2012 paper the breakthrough, or was Zhang’s 2013 paper the key advance? Ultimately, the court ruled in February that the patent should go to Zhang and the Broad Institute, Harvard University and the Massachusetts Institute of Technology. In the July, the University of California and others on Doudna’s side said they <a href="https://globenewswire.com/news-release/2017/07/25/1058142/0/en/CRISPR-Therapeutics-Intellia-Therapeutics-Caribou-Biosciences-and-ERS-Genomics-Announce-Appellate-Brief-Seeking-Reversal-of-U-S-Patent-Board-Decision-on-CRISPR-Cas9-Gene-Editing.html">were launching</a> an appeal of the decision. But the important thing is that CRISPR has<strong> </strong>arrived.</p>
<h3 id="0M2Wju">So what can we use CRISPR for?</h3>
<figure class="e-image">
<img alt=" " data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/rOzE7wQO7MZT8o1bW4HbAie7yT4=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/7220933/shutterstock_81557950.jpg">
<cite>Shutterstock</cite>
<figcaption>What am I in for now. </figcaption>
</figure>
<p id="hkJPHh">So many things. <a href="http://www.ipscell.com/">Paul Knoepfler</a>, an associate professor at UC Davis School of Medicine, <a href="http://www.vox.com/2015/5/4/8547797/what-is-crispr">told Vox</a> that CRISPR makes him feel like a "kid in a candy store." </p>
<p id="Zk0ynm">At the most basic level, CRISPR can make it much easier for researchers to figure out what different genes in different organisms actually <em>do — </em>by, for instance, knocking out individual genes and seeing what traits are affected. This is important: While we’ve had a <a href="https://en.wikipedia.org/wiki/Human_Genome_Project">complete “map” of the human genome</a> since 2003, we don’t really know what function all those genes serve. CRISPR can help speed up genome screening, and genetics research <a href="http://www.nature.com/news/crispr-gene-editing-is-just-the-beginning-1.19510">could advance massively as a result</a>.</p>
<p id="NCtn7j">Researchers have also discovered there are numerous CRISPRs. So CRISPR is actually a pretty broad term. “It’s like term fruit — it describes whole category,” said the Broad’s Zhang. When people talk about CRISPR, they are usually referring to the CRISPR/Cas9 system we’ve been talking about here. But in recent years, researchers like Zhang have found other types of CRISPR proteins that also work as gene editors. Cas13, for example, can edit DNA’s sister, RNA. “Cas9 and Cas13 are like apples and bananas,” Zhang added. </p>
<p id="9OqRxz">The real fun — and, potentially, the real risks — could come from using CRISPRs to edit various plants and animals. A <a href="http://www.nature.com/nbt/journal/v34/n9/full/nbt.3659.html">recent paper</a> in <em>Nature Biotechnology </em>by Rodolphe Barrangou and Doudna listed a flurry of potential applications in the future:</p>
<p id="3l17dE"><strong>1) Edit crops to be more nutritious:</strong> Crop scientists are already looking to use CRISPR to <a href="https://www.fastcoexist.com/3056693/crispr-is-going-to-revolutionize-our-food-system-and-start-a-new-war-over-gmos">edit the genes of various crops</a> to make them tastier, or more nutritious, or better survivors of heat and stress. They could potentially use CRISPR to snip out the allergens in peanuts. Korean researchers are looking to see if CRISPR could help bananas survive a deadly fungal disease. Some scientists have shown that CRISPR can <a href="http://www.nature.com/nbt/journal/v34/n5/full/nbt.3560.html">create hornless dairy cows</a> — a huge advance for animal welfare. </p>
<p id="pp4RBc">Over the past year, major companies like <a href="https://www.statnews.com/2016/09/22/monsanto-licenses-crispr/">Monsanto</a> and <a href="http://www.dupont.com/corporate-functions/media-center/press-releases/dupont-and-caribou-biosciences-announce-strategic-alliance.html">Dupont</a> have begun licensing CRISPR technology, hoping to develop valuable new crop varieties. While this technique won’t entirely replace traditional GMO techniques — which can transplant genes from one organism to another — CRISPR is a versatile new tool that can help identify genes associated with desired crop traits much more quickly. It could also allow scientists to insert desired traits into crops more precisely than traditional breeding, which is a much messier way of swapping in genes.</p>
<p id="kokcNg">“With genome editing, we can absolutely do things we couldn’t do before,” says Pamela Ronald, a plant geneticist at University of California Davis. That said, she cautions that it’s only one of many tools for crop modification out there — and the challenge of successfully breeding new varieties could still take years of testing. </p>
<p id="IwW1zh">It’s also possible that these new tools could attract controversy. Foods that have had a few genes knocked out via CRISPR <a href="http://www.vox.com/2016/5/18/11690992/gmos-review-evidence-safety-health">are currently regulated more lightly</a> than traditional GMOs. Policymakers in Washington, DC, are currently debating whether it might make sense to rethink regulations here. This piece for Ensia by Maywa Montenegro <a href="http://ensia.com/voices/crispr-is-coming-to-agriculture-with-big-implications-for-food-farmers-consumers-and-nature/">delves into some of the debates</a> CRISPR raises in agriculture.</p>
<p id="vpiEkA"><strong>2) New tools to stop genetic diseases: </strong>As the new <em>Nature</em> paper shows, scientists are now using CRISPR/Cas9 to edit the human genome and try to knock out genetic diseases like hypertrophic cardiomyopathy. They’e also looking at using it on mutations that cause Huntington’s disease or cystic fibrosis, and are talking about trying it on the BRCA-1 and 2 mutations linked to breast and ovarian cancers. Scientists have even shown that CRISPR can knock HIV infections <a href="http://www.pnas.org/content/111/31/11461.abstract">out of T cells</a>.</p>
<p id="QltHiA">So far, however, scientists have only tested this on cells in the lab. There are still <a href="http://www.pnas.org/content/112/20/6245.full#ref-20">a few hurdles to overcome</a> before anyone starts clinical trials on actual humans. For example: The Cas9 enzymes <a href="https://www.statnews.com/2016/07/18/crispr-off-target-effects/">can occasionally “misfire”</a> and edit DNA in unexpected places, which, in human cells, might lead to cancer or even create new diseases. Over the past year, <a href="https://www.statnews.com/2016/04/20/clever-crispr-advance-unveiled/">there have been major advances</a> in improving CRISPR precision and reducing these off-target effects, but scientists are urging caution on human testing until standards can be developed here. There’s also plenty of work yet to be done in actually delivering the editing molecules to particular cells — a major challenge going forward.</p>
<p id="5zp6PN"><strong>3) Powerful new antibiotics and antivirals</strong><strong>:</strong> One of the most frightening public health facts around is that <a href="http://www.vox.com/2016/9/20/12979968/antibiotic-resistance-superbugs-un">we are running low on effective antibiotics</a> as bacteria evolve resistance to them. Currently, it’s difficult and costly to develop fresh antibiotics for deadly infections. But CRISPR/Cas9 systems could, in theory, be developed to eradicate certain bacteria more precisely than ever (though, again, figuring out delivery mechanisms will be a challenge). Other researchers are working on CRISPR systems that target viruses such as HIV and herpes. </p>
<p id="A9i9Fk"><strong>4) Gene drives could alter entire species: </strong>Scientists have also demonstrated that CRISPR could be used, in theory, to modify not just a single organism but to modify an <em>entire species</em>. It’s an unnerving concept called <a href="http://www.vox.com/2016/6/9/11890472/gene-drive-benefits-risk">“gene drive.”</a></p>
<p id="MCDRtI">It works like this: Normally, whenever an organism like a fruit fly mates, there’s a 50-50 chance that it will pass on any given gene to its offspring. But using CRISPR, scientists can alter these odds so that there’s a nearly 100 percent chance that a particular gene gets passed on. Using this gene drive, scientists could ensure that an altered gene soon propagates throughout an entire population in short order:</p>
<figure class="e-image">
<img alt=" " data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/r_-jyTW7r3heg08vJKL08GnVGHo=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/7724927/Artboard_3.jpg">
<cite>Javier Zarracina; <a class="ql-link" href="http://rifters.com/real/articles/Science-2014-Oye-626-8.pdf" target="_blank">Oye et al. 2014</a></cite>
</figure>
<p id="w5Z9Mb">By harnessing this technique, scientists could (say) genetically modify mosquitoes to only produce male offspring — and then use gene drive to push that trait through an entire population. Over time, the population would go extinct. Or we could modify ticks so that they don’t spread Lyme, or eliminate weeds. You name it.</p>
<p id="7AVhnc">Suffice to say, there are lots of concerns about unintended side effects here, and the National Academy of Sciences <a href="http://www.vox.com/2016/6/9/11890472/gene-drive-benefits-risk">has recommended a moratorium</a> on deploying this technology until we better understand its impacts.</p>
<p id="4alFnd"><strong>5) Creating </strong><strong>“</strong><strong>designer babies.</strong><strong>”</strong><strong> </strong>This is the one that gets all the attention. It’s not entirely far-fetched to think we might one day use CRISPR to edit the human genome — to eliminate disease, or select for athleticism, or for superior intelligence.</p>
<p id="ZQDkW4">That said, scientists aren’t even close to being able to do this. We’re not even close to the point where scientists could safely make the complex changes needed to, say, improve intelligence. So don’t go dreaming of <a href="https://en.wikipedia.org/wiki/Gattaca">Gattaca</a> just yet.</p>
<p id="zMs2mR">“I think the reality is we don't understand enough yet about the human genome, how genes interact, which genes give rise to certain traits, in most cases, to enable editing for enhancement today," Doudna <a href="http://www.vox.com/2015/12/3/9845230/crispr-gene-editing-caution">told my colleague</a> Julia Belluz. Still, she added: "That’ll change over time."</p>
<h3 id="kxHFiX">Wait, should we really create designer babies?</h3>
<figure class="e-image">
<img alt=" " data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/Y8d4D7UVpVgDlIwR5lQP5LCWeoE=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/7220099/shutterstock_299699342.jpg">
<cite>(Shutterstock)</cite>
<figcaption>Can’t wait to have a superhuman sister.</figcaption>
</figure>
<p id="CJU5Jy">Given all the fraught issues associated with editing the human genome, many scientists are advocating a go-slow approach here.</p>
<p id="kOicUN">In February, a <a href="http://www8.nationalacademies.org/onpinews/newsitem.aspx?RecordID=24623">report</a> from the National Academy of Sciences said that clinical trials could be greenlit in the future “for serious conditions under stringent oversight.” But it also made clear that “genome editing for enhancement should not be allowed at this time.”</p>
<p id="uUcvqu">Society still needs to grapple with all the ethical considerations at play here. For example, if we edited a germline, future generations wouldn’t be able to opt out. Genetic changes might be difficult to undo. Even this stance has worried some researchers, like <a href="http://www.nih.gov/about/director/04292015_statement_gene_editing_technologies.htm">Francis Collins</a> of the National Institute of Health, who has said the US government will not fund any genomic editing of human embryos.</p>
<p id="Y8WvYM"> In the meantime, researchers in the US who can drum up their own funding, along with others in UK, Sweden, and China <a href="http://www.nature.com/news/gene-editing-research-in-human-embryos-gains-momentum-1.19767">are moving forward</a> with their own experiments.</p>
<h3 id="uw4Btw">Further reading</h3>
<ul>
<li id="XifgSr">At Vox, we reported on <a href="https://www.vox.com/2017/10/25/16527370/crispr-gene-editing-harvard-mit-broad">2 new CRISPR tools overcome the scariest parts of gene editing</a>. </li>
<li id="tyKrct">Ezra Klein <a href="https://art19.com/shows/the-ezra-klein-show/episodes/e1c07fbc-b8dc-4378-9edc-d6699cddf00e">interviewed</a> UC-Berkeley’s Jennifer Doudna, one of the leading CRISPR researchers, on his podcast in October.</li>
<li id="BxBI0w">Carl Zimmer has been on the CRISPR beat for a long time. His 2015 piece in Quanta is <a href="https://www.quantamagazine.org/20150206-crispr-dna-editor-bacteria/">well worth reading</a>.</li>
<li id="vyXmqc">In 2016, <em>Nature </em><a href="http://www.nature.com/news/beyond-crispr-a-guide-to-the-many-other-ways-to-edit-a-genome-1.20388">explored</a> some of the subtle limitations of CRISPR — and the search for additional gene-editing tools. And <a href="http://www.nature.com/news/crispr-gene-editing-is-just-the-beginning-1.19510">this earlier <em>Nature </em>piece</a> by Heidi Ledford is a delightfully wonky dive into the ways researchers could use CRISPR to explore the genome. It’s also worth <a href="http://www.nature.com/nbt/journal/v34/n9/full/nbt.3659.html">checking out this paper</a> listing all the different future applications of CRISPR.</li>
</ul>
https://www.vox.com/science-and-health/2016/12/30/13164064/crispr-cas9-gene-editingBrad PlumerJavier ZarracinaEliza BarclayJulia BelluzUmair Irfan2017-12-21T11:47:00-05:002017-12-21T11:47:00-05:00The winter solstice is today: 7 things to know about the shortest day of the year
<figure>
<img alt="NASA's Solar Dynamics Observatory Pictures Released" src="https://cdn.vox-cdn.com/thumbor/_oxmWLS0WXG7J5A-woJV7H8ElNA=/0x512:4096x3584/1310x983/cdn.vox-cdn.com/uploads/chorus_image/image/52384059/98614338.0.jpeg" />
<figcaption>Photo by NASA/Goddard/SDO AIA Team via Getty Images</figcaption>
</figure>
<p id="p76dJP">The winter solstice is upon us: Thursday, December 21, will be the shortest day of 2017 for anyone living in the Northern Hemisphere. If pagan rituals are your thing, this is <a href="http://paganwiccan.about.com/od/yulerituals/tp/YuleRituals.htm">probably a big moment</a> for you. If not, the <a href="https://www.google.com/doodles/winter-solstice-2017-northern-hemisphere">official first day of winter</a> is neat for other reasons too.</p>
<p id="6LG9K0">Technically speaking, the winter solstice occurs when the sun is directly over the Tropic of Capricorn, or 23.5° south latitude. In 2017, this will occur at exactly 11:28 am Eastern time on December 21. (Google celebrated the moment with a special winter <a href="https://www.google.com/doodles/winter-solstice-2017-northern-hemisphere">solstice Google Doodle</a>.) </p>
<p id="8m7W9y">Below is a short scientific guide to the solstice and the longest night of the year (though not, as we’ll see, the longest night in Earth’s history — that happened back in 1912).</p>
<h3 id="J7QWFf">1) Why do we have a winter solstice, anyway?</h3>
<p id="x8o8V5">Most people know this one. Earth orbits around the sun on a tilted axis (likely <a href="http://www.universetoday.com/75897/why-is-the-earth-tilted/">because our planet collided</a> with some other massive object billions of years ago, back when it was still being formed).</p>
<p id="18YxuW">So between September and March, Earth’s Northern Hemisphere gets less exposure to direct sunlight over the course of a day. The rest of the year, the north gets <em>more</em> direct sunlight and the Southern Hemisphere gets less. It’s the reason for the seasons:</p>
<figure class="e-image">
<img alt="A graphic showing the tilt of the Earth’s axis throughout the year. In the wintertime, the south pole tilts toward the sun. In the summer, the north pole does. " data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/Bwm5VM_MMqwxaFaExpGKU3GcW3I=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/2757592/1280px-North_season.0.jpg">
<cite><a class="ql-link" href="http://en.wikipedia.org/wiki/File:North_season.jpg" target="_blank">Tauʻolunga</a></cite>
</figure>
<p id="gHOld3">In the Northern Hemisphere, "peak" sunlight usually occurs on June 20, 21, or 22 of any given year. That’s the summer solstice. By contrast, the Southern Hemisphere reaches peak sunlight on December 21, 22, or 23 and the north hits peak darkness — that’s our winter solstice.</p>
<p id="GQuxGB">In the Northern Hemisphere, the winter solstice occurs when the sun is directly overhead the Tropic of Capricorn, or 23.5° south latitude. <a href="http://scijinks.jpl.nasa.gov/solstice/">Like so</a>:</p>
<figure class="e-image">
<img alt=" " data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/udwU7JaDQew6izszG0ZDoaFU5oU=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/7678595/winter_solstice.jpg">
<cite><a class="ql-link" href="http://scijinks.jpl.nasa.gov/solstice/" target="_blank">NASA</a></cite>
</figure>
<p id="kIbD7e">In 2017, the winter solstice will occur at exactly 11:28 am Eastern Time. </p>
<h3 id="HpRXDW">2) How many hours of sunlight will I get on Thursday?</h3>
<p id="zFQW3X">That depends on where you live. The farther north from the equator you are, the less sunlight you’ll get during the solstice — and the longer the night will be. Alaska climatologist <a href="https://twitter.com/Climatologist49">Brian Brettschneider</a> created <a href="http://us-climate.blogspot.com/2016/06/daylight-twilight-astronomical-maps.html">this terrific guide</a> for the United States:</p>
<figure class="e-image">
<img alt=" " data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/9Tal7G6ook7B9jQABFUDNX7EeYs=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/7678631/SolsticeDaylight.jpg">
<cite>(<a href="http://us-climate.blogspot.com/2016/06/daylight-twilight-astronomical-maps.html">Brian Brettschneider</a>)</cite>
</figure>
<p id="FZD9Fa">Here in Washington, DC, we <a href="https://www.timeanddate.com/sun/usa/washington-dc">will get</a> nine hours and 26 minutes of sunlight. </p>
<p id="EheqsR">On the off chance you live near the Arctic Circle, you’ll barely get any daylight during the solstice. Fairbanks, Alaska, for instance <a href="https://www.timeanddate.com/sun/usa/fairbanks">will get</a> three hours and 41 minutes. (If you live north of the circle, you’ll get none at all.)</p>
<p id="3WqeGa">The time lapse below shows the eerie scene in Fairbanks — the sun basically skims the horizon for a brief while and then vanishes:</p>
<div id="yIjFWH"><div><div style="left: 0px; width: 100%; height: 0px; position: relative; padding-bottom: 56.2493%;"><iframe src="https://www.youtube.com/embed/Olbo4Am4U44?wmode=transparent&rel=0&autohide=1&showinfo=0&enablejsapi=1" frameborder="0" allowfullscreen="" style="top: 0px; left: 0px; width: 100%; height: 100%; position: absolute;"></iframe></div></div></div>
<p id="JG3cT5">(Brettschneider has more charts on the solstice, including the differences in daylight between winter and summer solstices; his <a href="http://us-climate.blogspot.com/2016/06/daylight-twilight-astronomical-maps.html">entire post</a> is worth your time.)</p>
<p id="TVAhLu">Here’s another cool way to visualize the extreme of the winter solstice. In 2013, a resident of Alberta, Canada — several hundred miles south of Fairbanks, but still in a high latitude — took this <a href="http://www.alternativephotography.com/wp/processes/pinholes/solargraphy-catching-the-suns-path-pinhole-camera">pinhole camera</a> photograph of the sun’s path throughout the year, and shared it with the astronomy <a href="http://earthsky.org/earth/everything-you-need-to-know-december-solstice">website EarthSky</a>. You can see the dramatic change in the arc of the sun from December to June. </p>
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<p>This is a 6 month pinhole photo taken from solstice to solstice, in Medicine Hat, Alberta, Canada. We are one of the sunniest cities in Canada, and this shows it nicely.</p>Posted by <a href="https://www.facebook.com/ihennes">Ian Hennes</a> on <a href="https://www.facebook.com/photo.php?fbid=10151815149866087&set=o.36709031852&type=3">Saturday, December 21, 2013</a>
</blockquote></div>
</div>
<p id="QOpzVB">(You can easily make a similar image at home. All you need is a can, photo paper, some tape, and a pin. <a href="http://petapixel.com/2015/04/29/how-to-make-a-diy-solargraphy-pinhole-camera-for-6-month-exposures/">Instructions here</a>.)</p>
<h3 id="faSUi9">3) Is the winter solstice the earliest sunset of the year?</h3>
<p id="0gWsqf">Not usually. Just because December 21 is the shortest day of the year for the Northern Hemisphere, it doesn’t<em> </em>mean every location has its earliest sunset or latest sunrise on that day.</p>
<p id="DA3eXa">Brettschneider also <a href="http://us-climate.blogspot.com/2016/06/daylight-twilight-astronomical-maps.html">created this map </a>showing earliest sunset/latest sunrise for different parts of North America:</p>
<figure class="e-image">
<img alt=" " data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/L4TYfjzv5tMdIeVkMTDMAncAGUc=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/7678669/NorthAmerica_SunriseSunsetOffset.jpg">
<cite><a class="ql-link" href="http://us-climate.blogspot.com/2016/06/daylight-twilight-astronomical-maps.html" target="_blank">Brian Brettschneider</a></cite>
</figure>
<p id="PWJZFd">If you live in DC, you missed the earliest sunset — it happened back on <a href="https://sunrise-sunset.org/us/washington-dc">December 6</a>. But you can still catch the latest sunrises on January 3 and 4. If you like <a href="http://www.vox.com/2016/3/18/11255942/morning-people-evening-chronotypes-sleeping">sleeping in</a>, that’s arguably the most exciting day of the winter. No annoying sun bothering you in the morning.</p>
<h3 id="2ILBiR">4) Is the winter solstice the <em>coldest </em>day of the year?</h3>
<figure class="e-image">
<img alt="Warm Temperatures Persist In Central Europe" data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/9BCWJIsRsQvJRVPZn8ReJYMu56I=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/7679137/502694798.jpg">
<cite>Philipp Guelland/Getty Images</cite>
</figure>
<p id="Dq8ioj">Not usually! It’s true that the Northern Hemisphere gets the least direct sunlight on the winter solstice (which is officially the first day of winter). But the coldest months are yet to come — usually in January or February, depending on where you live.</p>
<p id="nCm4Dv">A big reason for this <a href="https://en.wikipedia.org/wiki/Seasonal_lag">“seasonal lag”</a> is that the Earth’s massive oceans absorb much of the sun’s energy and release it slowly, over time. So there’s a delay between when there’s the least sun and when the air temperatures are actually coldest. The same thing happens in summer — there’s a delay between when solar insolation is at its maximum (the summer solstice in June) and when the hottest months are (usually July or August).</p>
<p id="9PXO6N">This seasonal lag varies greatly from place to place — during the summer, it’s pretty extreme in San Francisco, which is surrounded by water on three sides and where temperatures don’t typically peak until September. Likewise, places far from large bodies of water, like Iowa, <a href="https://www.insidescience.org/news/solstice-shmolstice-%E2%80%93-why-coldest-days-are-still-come">can often see sharper swings in temperature</a> than places like Rome that are surrounded by ocean.</p>
<h3 id="0pEwDt">5) What does all this have to do with Stonehenge?</h3>
<p id="xEnnXV">No one knows for sure why <a href="https://en.wikipedia.org/wiki/Stonehenge">Stonehenge</a> was built some 5,000 years ago (at least I don’t, sorry). But one strong possibility is that it was used to mark solstices and equinoxes. That’s because the structure is directly aligned toward the sunset during the winter solstice. (The sun also rises directly over the Heel Stone during the summer solstice.)</p>
<p id="CMUXeP">Why was the winter solstice a big deal? <a href="https://aas.org/posts/news/2016/11/month-astronomical-history-winter-solstice-archaeoastronomy">Here’s</a> Teresa Wilson of the American Astronomical Society to explain: “While the summer solstice draws a larger crowd, the winter solstice may have been more important to the ancient builders. At this time, cattle were slaughtered so the animals did not need to be fed through the winter, and wine and beer made previously had finally fermented.”</p>
<p id="7L9WBw">Nowadays, humans still gather to pay homage the winter solstice at Stonehenge — they just use modern technology. </p>
<figure class="e-image">
<img alt=" " data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/3jIxz4sL_IjgNOmrblUKXZle79g=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/7678869/GettyImages_158612084.jpg">
<cite>Matt Cardy/Getty Images</cite>
<figcaption>People gather to watch the sunrise as druids, pagans, and revelers celebrate the winter solstice at Stonehenge on December 21, 2012, in Wiltshire, England.</figcaption>
</figure>
<p id="iMomE9">At least the winter solstice at Stonehenge seems like a top-rate party: </p>
<figure class="e-image">
<img alt=" " data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/ApAyurhA3wBtWiaiBZUoY0E11J8=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/9896455/GettyImages_630338960__1_.jpg">
<cite>Matt Cardy/Getty Images</cite>
</figure>
<figure class="e-image">
<img alt=" " data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/kn-04YgW6-608JCWOX4k4ciYnlc=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/9896449/GettyImages_630339492.jpg">
<cite>Matt Cardy/Getty Images</cite>
</figure>
<p id="JoPdSY">The <a href="https://en.wikipedia.org/wiki/Stonehenge">Wikipedia entry on Stonehenge</a> is absurdly detailed, so read up on that if you want more. And Vox’s Joss Fong created this video to explain how Stonehenge was (probably) constructed.</p>
<div id="XLjnTM">
<div data-analytics-viewport="video" data-analytics-action="volume:view:article:middle" data-analytics-label="Decoding the ancient astronomy of Stonehenge|29298" data-volume-uuid="110f06443" data-volume-id="29298" data-analytics-placement="article:middle" data-volume-placement="article" data-volume-autoplay="false" id="volume-placement-166" class="volume-video" data-volume-player-choice="youtube"></div>
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<h3 id="qQtPHy">6) Is Thursday the longest night in Earth’s entire history?</h3>
<p id="A2n84E">Probably not, although it's close. And the reason why is quite interesting. My colleague Joseph Stromberg did <a href="http://www.vox.com/2014/12/23/7441951/earth-rotation">a fantastic deep dive</a> into this topic a few years back, but here’s the two-minute version.</p>
<p id="aqFLOg">Ever since the Earth has had liquid oceans and a moon, its rotation has been gradually slowing over time due to <a href="http://www.physics.mcgill.ca/~crawford/PSG/PSG11/204_97_L11.9_tidfric.html">tidal friction</a>. That means that over very, very long periods of time, the days have been getting steadily longer. About 4.5 billion years ago, it took the Earth just six hours to complete one rotation. About 350 million years ago, it took 23 hours. Today, of course, it takes about <a href="https://en.wikipedia.org/wiki/Earth%27s_rotation">24 hours</a>. And the days will gradually get longer still.</p>
<p id="rbJuuH">Given that, you'd <em>think</em> the winter solstice of 2016 would be the longest night in all of history. But while it's certainly up there, it doesn't quite take top honors.</p>
<figure class="e-image">
<img alt="spinning globe" data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/FErrbkI_Vp9DEOJcAyufvixyE7c=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/2874598/shutterstock_33299590.0.jpg">
<cite>Shutterstock</cite>
</figure>
<p id="6WJTf0">That's because tidal friction isn’t the <em>only</em> thing affecting the Earth’s rotation — there are a few countervailing factors. The melting of glacial ice, which has been occurring since the end of the last ice age 12,000 years ago (and is now ramping up because of <a href="http://www.vox.com/cards/global-warming">global warming</a>) is actually speeding up<em> </em>Earth’s rotation very slightly, shortening the days by a few fractions of a millisecond. Likewise, geologic activity in the Earth’s core, earthquakes, ocean currents, and seasonal wind changes can also speed up or slow down the planet's rotation.</p>
<p id="9zZkJr">When you put all these factors together, scientists have estimated that the longest day in Earth’s history (so far) likely occurred <a href="http://www.ucolick.org/~sla/leapsecs/amsci.html">back in 1912</a>. That year’s summer solstice was the longest period of daylight the Northern Hemisphere has ever seen. And, conversely, the 1912 winter solstice was the longest night we’ve ever seen.</p>
<p id="jHOzMI">Eventually, the effects of tidal friction should overcome all those other factors, and Earth’s days will get longer and longer as the planet’s rotation keeps slowing (forcing timekeepers to add <a href="http://www.ucolick.org/~sla/leapsecs/amsci.html">leap seconds</a> to the calendar periodically). Which means that in the future, there will be plenty of winter solstices that set new records as the "longest night in Earth's history."</p>
<h3 id="r2PX6l">7) I clicked this article accidentally and really just want a cool picture of the sun</h3>
<p id="hKMA0k">We got you:</p>
<figure class="e-image">
<img alt=" " data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/kARAvZHyJzccneMEWMxE48gZETA=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/9896465/Outburst304.jpg">
<cite>Solar Dynamics Observatory/NASA</cite>
<figcaption>The sun blew out a coronal mass ejection along with part of a solar filament over a three-hour period (February 24, 2015). Some of the strands fell back into the sun.</figcaption>
</figure>
<p id="STd5jn">The image above <a href="http://www.nasa.gov/mission_pages/sdo/news/first-light.html">was taken</a> by NASA’s Solar Dynamics Observatory, a spacecraft launched in 2010 to better understand the sun.</p>
<p id="OOOSNB">In 2018, NASA will launch the <a href="https://www.nasa.gov/feature/goddard/2017/nasa-renames-solar-probe-mission-to-honor-pioneering-physicist-eugene-parker/">Parker Probe Plus</a>, a spacecraft that will come within 4 million miles of the surface of the sun (much closer than any spacecraft has been before). The goal is to study the sun’s atmosphere, weather, and magnetism, and figure out the mystery of why the sun’s corona (its atmosphere) <a href="https://www.theatlantic.com/science/archive/2017/05/its-lit/528594/">is much hotter than its surface</a>. Still, even several million miles away, the probe will have to withstand temperatures of 2,500 degrees Fahrenheit.</p>
<p id="9pDecg">It’s essential to understand the sun: It’s nothing to mess with. <a href="http://www.vox.com/2014/7/30/5951263/a-catastrophic-solar-storm-just-barely-missed-earth-in-2012">Brad Plumer wrote</a> about what happens when the sun erupts and sends space weather our way to wreak havoc on Earth. </p>
<p id="uv4YNV">Happy solstice!</p>
https://www.vox.com/2016/12/20/14027402/winter-solstice-2017Brad PlumerBrian Resnick2017-09-12T15:46:18-04:002017-09-12T15:46:18-04:00How do hurricanes form? A step-by-step guide.
<figure>
<img alt="Hurricane Harvey began as a mere tropical wave near the west coast of Africa." src="https://cdn.vox-cdn.com/thumbor/TPfkayvhle-3dOCpT9X8Hj3S6WI=/0x0:2400x1800/1310x983/cdn.vox-cdn.com/uploads/chorus_image/image/51231539/harvey_goes_82517.1503677197.jpg" />
<figcaption>Hurricane Harvey began as a mere tropical wave near the west coast of Africa. | NASA/NOAA GOES Project</figcaption>
</figure>
<p id="bXt40O">Whenever <a href="https://en.wikipedia.org/wiki/Atlantic_hurricane_season">hurricane season arrives</a> in the Atlantic Ocean — typically between June and November — a bunch of meteorological terms get hurled around. Tropical storm. Tropical depression. Category 3 hurricanes. Category 4 hurricanes.</p>
<p id="iqOnNc">So what’s the difference between all these types of weather events? One way to understand this is to walk through the different stages of a hurricane, step by step. We’ll use <a href="https://en.wikipedia.org/wiki/Hurricane_Irma">Hurricane Irma</a>, which started out as a wave off the African coast and went on to pound several Caribbean before it hit Florida as a Category 4 storm in 2017, as an example:</p>
<p id="eKd9Sh"><strong>1) Tropical disturbance:</strong> A hurricane in the Atlantic Ocean typically begins life as a lowly <a href="http://www.aoml.noaa.gov/hrd/tcfaq/A5.html">“tropical disturbance”</a> — defined as organized thunderstorm activity that stretches at least 100 miles across and maintains its identity for more than 24 hours. </p>
<p id="l8TOwx">During the summer, these disturbances often start as storms moving westward off the coast of Africa in what are known as “tropical waves.”</p>
<figure class="e-image">
<img alt=" " data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/Nngs6sm4sKu6KSNjnXYePhsuB0o=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/7232551/Twaves.jpg">
<cite>(NOAA)</cite>
<figcaption>Tropical wave formation.</figcaption>
</figure>
<p id="UKm85v">If meteorologists think a tropical disturbance may develop further, they’ll designate it as an “investigative area,”<strong> </strong>or <a href="https://en.wikipedia.org/wiki/Invest_(meteorology)">invest</a>.<strong> </strong>Irma became a disturbance off the Cape Verde Islands in late<strong> </strong>August, with forecasters keeping close watch as it headed west.</p>
<p id="B8m1us"><strong>2) Tropical depression or cyclone: </strong>Under the right conditions, a tropical disturbance can develop further and start to spin around a low-pressure center. Once that happens, it’s classified as a "tropical cyclone" or "tropical depression":</p>
<figure class="e-image">
<img alt=" " data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/cixVBw9gT9b9LttKspmON1i6ctQ=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/7232565/bf899495261cc15db80e1508ca6ae20309bace26%20(1).png">
<cite>(<a href="http://www.bbc.co.uk/bitesize/ks3/geography/physical_processes/weather_climate/revision/9/">BBC</a>)</cite>
</figure>
<p id="fdzYKb">For a tropical depression to form, conditions have to be just right: The water <a href="http://www.aoml.noaa.gov/hrd/tcfaq/A5.html">has to be warm enough</a> to fuel the system, with temperatures of 80°F or hotter. There needs to be enough moisture in the lower and middle part of the atmosphere. Local winds also have to be arranged so that they allow the depression to spin — too much <a href="https://en.wikipedia.org/wiki/Wind_shear">wind shear</a> can tear an aspiring tropical cyclone apart.</p>
<p id="B09luD"><strong>3) Tropical storm: </strong>This is the next stage. When the pressure in the center of the tropical depression drops, air rushes in, creating strong winds. If the system strengthens and wind speeds rise past 39 mph, the system is dubbed a “tropical storm” and <a href="http://www.nhc.noaa.gov/aboutnames.shtml">is given a name</a>. That's what happened to Irma on <a href="http://www.nhc.noaa.gov/archive/2017/al11/al112017.public.001.shtml">August 30</a>, as it picked up speed in the far Eastern Atlantic and intensified.</p>
<p id="d5HooV">The US National Hurricane Center makes the call for when a tropical depression officially becomes a tropical storm. It relies on data from islands and buoys as well as from reconnaissance aircrafts that fly into the storms to measure wind speed.</p>
<p id="iX99aa"><strong>4) Hurricane:</strong> Tropical storms can intensify quickly if they pass over a region of especially warm water and don’t face much wind shear. As that happens, the pressure in the center drops even further and the winds <em>really</em> pick up. The system gets rounder and often forms a clearly defined "eye." Here's Irma on Wednesday:</p>
<div id="xZubyq">
<blockquote class="twitter-tweet">
<p lang="en" dir="ltr">The huge eye of Category 5 Hurricane <a href="https://twitter.com/hashtag/Irma?src=hash">#Irma</a> completely engulfed the island of Barbuda last night, captured by the Suomi NPP <a href="https://twitter.com/hashtag/VIIRS?src=hash">#VIIRS</a> overpass. <a href="https://t.co/BKNFgx8r4V">pic.twitter.com/BKNFgx8r4V</a></p>— UW-Madison CIMSS (@UWCIMSS) <a href="https://twitter.com/UWCIMSS/status/905440642091888641">September 6, 2017</a>
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<script async="" src="//platform.twitter.com/widgets.js" charset="utf-8"></script>
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<p id="zhLzxr">When the winds reach sustained speeds of 74 mph or more, the storm system is classified as a hurricane. Hurricanes are categorized according to the <a href="http://www.nhc.noaa.gov/aboutsshws.php">Saffir-Simpson Scale</a> based on their wind speed and propensity for damage. </p>
<figure class="e-image">
<img alt="A chart describing storms labeled Category 1 (winds up to 95 miles per hour, isolated injuries) through Category 5 (winds above 155 mph, extreme flooding)." data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/pR1cWA24L9reOSgpbPBse8zRifk=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/7238885/scale.png">
<cite>Zachary Crockett/Vox</cite>
</figure>
<p id="N1W9xo">Irma was<strong> </strong>a Category 5 as of September 5 with wind speeds of 185 miles per hour. That’s serious — major hurricanes can do structural damage to buildings, take down trees, and cause widespread flooding.</p>
<p id="pffxTa">Side note: The fact that you need especially warm water here explains why hurricanes only form in the Atlantic during the late summer months. (It also helps explain why global warming <a href="https://www.gfdl.noaa.gov/global-warming-and-hurricanes/">may lead to stronger hurricanes</a>, although this gets complicated, since climate change <a href="https://www.washingtonpost.com/news/energy-environment/wp/2016/10/06/heres-what-we-can-say-about-climate-change-and-hurricane-matthew/?utm_term=.ffec23f570f1">can also affect wind shear</a> that suppresses hurricanes.)</p>
<p id="eJBaxU"><strong>5) Back down to tropical storm: </strong>Hurricanes can also weaken, however, as they move over land (or cooler water) and no longer have warm, moist air to fuel them. Once wind speeds drop below 75 miles per hour, the hurricane gets downgraded to a tropical storm — and, later on, a <a href="https://en.wikipedia.org/wiki/Post-tropical_cyclone">"post-tropical cyclone"</a> as it degrades further.</p>
<p id="a0pGjs">For example, Hurricane Hermine in 2016 was downgraded to a tropical storm not long after it made landfall in Florida in September. But then Hermine <a href="http://www.vox.com/2016/9/2/12768798/hurricane-vs-tropical-storm">moved <em>back</em> over</a> the Atlantic Ocean and hit record-warm ocean temperatures there, gathering to hurricane strength again.</p>
<p id="yOMTab">It’s worth emphasizing that even tropical cyclones that <em>aren’t</em> hurricanes can still do a great deal of damage by bringing torrential rain, dangerous surf, beach erosion, high winds, and flooding. In 2012, <a href="https://en.wikipedia.org/wiki/Hurricane_Sandy">"superstorm" Sandy</a> was technically no longer a hurricane when it hit the East Coast, but it still proved devastating to the New York and New Jersey coasts.</p>
https://www.vox.com/science-and-health/2016/10/6/13191010/how-do-hurricanes-form-tropical-storms-guideBrad PlumerRuairí Arrieta-Kenna2017-06-21T15:01:59-04:002017-06-21T15:01:59-04:00The summer solstice is upon us: 7 things to know about the longest day of the year
<figure>
<img alt="" src="https://cdn.vox-cdn.com/thumbor/1sCUdk7mpCIOBfZm7f4tA561gPM=/0x165:985x904/1310x983/cdn.vox-cdn.com/uploads/chorus_image/image/55337161/446589main_fulldiskmulticolor-orig_full.0.jpg" />
<figcaption>(NASA/Goddard/SDO AIA Team)</figcaption>
</figure>
<p>Why do we have a summer solstice, anyway?</p> <p id="p76dJP">The summer solstice is upon us: June 20th and the 21st will be the longest days of 2017 for anyone living north of the equator. If pagan rituals are your thing, this is <a href="https://thepaganandthepen.wordpress.com/2010/06/20/celebrating-the-pagan-summer-solstice/">probably a big moment for you</a>. If not, the solstice is still pretty neat.</p>
<p id="oSH1Sc">Technically speaking, the summer solstice occurs when the sun is directly overhead the Tropic of Cancer, or 23.5° north latitude. In 2017, this will occur at exactly 12:24 am (Eastern) on the 21st. (But we can celebrate on either day.) </p>
<p id="8m7W9y">Below is a short scientific guide to the longest day of the year (though not, as we’ll see, the longest day in Earth’s history — that happened back in 1912).</p>
<h3 id="J7QWFf">1) Why do we have a summer solstice, anyway?</h3>
<p id="x8o8V5">Okay, most people know this one. Earth orbits around the sun on a tilted axis (probably <a href="http://www.universetoday.com/75897/why-is-the-earth-tilted/">because our planet collided</a> with some other massive object billions of years ago, back when it was still being formed).</p>
<p id="18YxuW">So between March and September, Earth’s Northern Hemisphere gets more exposure to direct sunlight over the course of a day. The rest of the year, the Southern Hemisphere gets more. It’s the reason for the seasons:</p>
<figure class="e-image">
<img alt=" " data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/HjgZQTFfAIl9irU7Xno95i8zMwk=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/6669949/1280px-North_season.0.jpg">
<cite><a href="http://en.wikipedia.org/wiki/File:North_season.jpg" target="_blank">Tauʻolunga</a></cite>
</figure>
<p id="gHOld3">In the Northern Hemisphere, "peak" sunlight usually occurs on June 20, 21, or 22 of any given year. That’s the summer solstice. By contrast, the Southern Hemisphere reaches peak sunlight on December 21, 22, or 23 and the north hits peak darkness — that’s our winter solstice.</p>
<figure class="e-image">
<img alt=" " data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/e5BWzIOubpffY9EZdK3--HQ8Nlg=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/6669953/summer-solstice-large.jpg">
<cite><a href="http://scijinks.jpl.nasa.gov/solstice/" target="_blank">NASA</a></cite>
</figure>
<h3 id="HpRXDW">2) How many hours of sunlight will I get on Tuesday?</h3>
<p id="zFQW3X">That depends on where you live. The further north you are, the more sunlight you’ll see during the solstice. Alaska-based climatologist <a href="https://twitter.com/Climatologist49">Brian Brettschneider</a> created <a href="http://us-climate.blogspot.com/2016/06/daylight-twilight-astronomical-maps.html">this terrific guide</a>:</p>
<figure class="e-image">
<img alt=" " data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/O5tjdTOu5dSHpit6fcPOHj5dVro=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/8712611/Daylight_Sum_Solstice_Times__1_.jpg">
</figure>
<p id="FZD9Fa">On the off chance you live near the Arctic Circle, the sun never really sets during the solstice. </p>
<div id="Gbm5Or"><div style="left: 0; width: 100%; height: 0; position: relative; padding-bottom: 56.2493%;"><iframe src="https://www.youtube.com/embed/-56bafZE9-A?rel=0&amp;controls=2" style="border: 0; top: 0; left: 0; width: 100%; height: 100%; position: absolute;" allowfullscreen="" scrolling="no"></iframe></div></div>
<p id="U89yoX">(By contrast, during the winter solstice, Fairbanks only gets about three hours of sunlight.)</p>
<p id="QhonXJ">Here’s another cool way to visualize the extreme of the summer solstice. In 2013, a resident of Alberta, Canada — several hundred miles south of Fairbanks, but still in a high latitude — took this <a href="http://www.alternativephotography.com/wp/processes/pinholes/solargraphy-catching-the-suns-path-pinhole-camera">pinhole camera</a> photograph of the sun’s path throughout the year, and shared it with the astronomy <a href="http://earthsky.org/earth/everything-you-need-to-know-december-solstice">website EarthSky</a>. You can see the dramatic change in the arc of the sun from December to June. (You can easily make a similar image at home. All you need is a can, photo paper, some tape, and a pin. <a href="http://petapixel.com/2015/04/29/how-to-make-a-diy-solargraphy-pinhole-camera-for-6-month-exposures/">Instructions here</a>.)</p>
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<p>This is a 6 month pinhole photo taken from solstice to solstice, in Medicine Hat, Alberta, Canada. We are one of the sunniest cities in Canada, and this shows it nicely.</p>Posted by <a href="https://www.facebook.com/ihennes">Ian Hennes</a> on <a href="https://www.facebook.com/photo.php?fbid=10151815149866087&set=o.36709031852&type=3">Saturday, December 21, 2013</a>
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<p id="WzJytD">Note that the solstice also gives us the longest twilight of the year, usually about <a href="http://us-climate.blogspot.com/2016/06/daylight-twilight-astronomical-maps.html">1 to 1.5 extra hours</a> after sunset. (Brettschneider has more charts on that; his <a href="http://us-climate.blogspot.com/2016/06/daylight-twilight-astronomical-maps.html">entire post</a> is worth your time.)</p>
<p id="1FldZV">Side note: This year, <a href="http://www.vox.com/2016/6/6/11851766/ramadan-2016-muslim-about">the Muslim holy month of Ramadan</a> coincides with the solstice. (Ramadan’s dates vary each year, but in 2017 it runs from May 26 to June 24.) Which makes for a grueling challenge in some places: Muslims are supposed to fast until sunset during Ramadan, but for those living in Norway, Sweden, or Iceland, daylight can last up to 20 hours. "In these cases," Vox's Jennifer Williams <a href="http://www.vox.com/2016/6/6/11851766/ramadan-2016-muslim-about">explains</a>, "Muslim religious authorities have decreed that Muslims can either fast along with the closest Muslim country or fast along with Mecca, Saudi Arabia."</p>
<h3 id="ihX6bt">3) Is the solstice the latest sunset of the year?</h3>
<p id="cUj1Sm">Not necessarily. Just because June 20 is the longest day of the year for the Northern Hemisphere doesn’t<em> </em>mean every location has its earliest sunrise or latest sunset on that day.</p>
<p id="pKV5XA">If you live in Washington, DC, you missed the earliest sunrise — it happened back on June 13. But you can still catch the latest sunset on June 27. If you like <a href="http://www.vox.com/2016/3/18/11255942/morning-people-evening-chronotypes-sleeping"><strong>sleeping in</strong></a>, that’s arguably the most exciting day of the summer.</p>
<h3 id="m51WhU">4) What does all this have to do with Stonehenge?</h3>
<p id="xEnnXV">No one really knows why <a href="https://en.wikipedia.org/wiki/Stonehenge"><strong>Stonehenge</strong></a> was built some 5,000 years ago (at least I don’t, sorry). But one possibility is that it was used to mark solstices and equinoxes. That’s because during the summer solstice, the sun rises just over the structure’s Heel Stone and hits the Altar Stone dead center.</p>
<p id="tExjNV">Here’s <a href="http://scijinks.jpl.nasa.gov/solstice/"><strong>a graphic</strong></a> from NASA imagining what a summer solstice sunrise might’ve looked like back when Stonehenge was fully intact:</p>
<figure class="e-image">
<img alt=" " data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/rGoHyxqxvHXuALLkWJ0pFCcumcs=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/6670057/stonehenge_brown-large.jpg">
<cite><a href="http://scijinks.jpl.nasa.gov/solstice/" target="_blank">NASA</a></cite>
</figure>
<p id="1tKMBx">Nowadays, humans still gather to pay homage the summer solstice at Stonehenge — they just use modern technology, like so:</p>
<figure class="e-image">
<img alt="Thousands Gather To Celebrate Summer Solstice At Stonehenge" data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/k6hgJEkUselJoYrByjUENywtImg=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/8712717/450970748.jpg">
<cite>Tim Ireland/Getty Images</cite>
</figure>
<p id="7TYfHt">The <a href="https://en.wikipedia.org/wiki/Stonehenge"><strong>Wikipedia entry on Stonehenge</strong></a> is absurdly detailed, so read up on that if you want more.</p>
<h3 id="aWjNDR">5) Is this the longest day in Earth’s entire history?</h3>
<p id="A2n84E">Probably not, although it's close. And the reason why is quite interesting. Joseph Stromberg did <a href="http://www.vox.com/2014/12/23/7441951/earth-rotation"><strong>a fantastic deep dive</strong></a> into this topic for Vox a few years back, but here’s the two-minute version.</p>
<p id="aqFLOg">Ever since the Earth has had liquid oceans and a moon, its rotation has been gradually slowing over time due to <a href="http://www.physics.mcgill.ca/~crawford/PSG/PSG11/204_97_L11.9_tidfric.html"><strong>tidal friction</strong></a>. That means — over very, very long periods of time — the days have been getting steadily longer. About 4.5 billion years ago, it took the Earth just six hours to complete one rotation. About 350 million years ago, it took 23 hours. Today, of course, it takes about <a href="https://en.wikipedia.org/wiki/Earth%27s_rotation"><strong>24 hours</strong></a>. And the days will gradually get longer still.</p>
<p id="vzMDRn">Given that, you'd <em>think</em> 2017 would be the longest day in all of history. But while it's certainly up there, it doesn't quite take top honors.</p>
<p id="xuCQbe">That's because tidal friction isn’t the <em>only</em> thing affecting Earth’s rotation — there are a few countervailing factors. The melting of glacial ice, which has been occurring since the end of the last ice age 12,000 years ago (and is now ramping up because of <a href="http://www.vox.com/cards/global-warming">global warming</a>), is actually speeding up<em> </em>Earth’s rotation very slightly, shortening the days by a few fractions of a millisecond. Likewise, geologic activity in the planet’s core, earthquakes, ocean currents, and seasonal wind changes can also speed up or slow down Earth’s rotation.</p>
<p id="9zZkJr">When you put all these factors together, scientists have estimated that the longest day in Earth’s history (so far) likely occurred <a href="http://www.ucolick.org/~sla/leapsecs/amsci.html"><strong>back in 1912</strong></a>. That year’s summer solstice was the longest period of daylight the Northern Hemisphere has ever seen (and, conversely, the 1912 winter solstice was the longest night we’ve ever seen).</p>
<p id="HMyXgX">Eventually, the effects of tidal friction should overcome all those other factors, and Earth’s days will get longer and longer as its rotation keeps slowing (forcing timekeepers to add <a href="http://www.ucolick.org/~sla/leapsecs/amsci.html"><strong>leap seconds</strong></a> to the calendar periodically). Which means that in the future, there will be plenty of summer solstices that set new records as the "longest day in Earth's history."</p>
<h3 id="BlKbEv">6) Isn’t there going to be a solar eclipse? </h3>
<figure class="e-image">
<img alt=" " data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/l6YfcTQ23lXObIx_klRAx25LUhw=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/8691273/usa_eclipse_map_16x9_1920x1080.jpg">
</figure>
<p id="tH9X6N">No, not on the solstice. </p>
<p id="eSHFzF">But there <a href="https://www.vox.com/science-and-health/2017/6/15/15804336/2017-solar-eclipse-map-united-states-nasa"><em>will</em> be a rare solar eclipse</a> across the entire continental US a bit later in the summer, on August 21. </p>
<p id="U0W7wF">On that day, the Earth, moon, and sun will be in perfect alignment to cast a 60-mile-wide shadow that will trace itself across the country like a dark laser pointer on a whiteboard. </p>
<p id="6GdPAS">In the bull’s eye center of the moon’s shadow known as the totality, the sky will go dark for a few minutes in the middle of the day, stars will appear, and birds will become confused and start chirping their nighttime songs. And it’s all because of a cosmic coincidence: From the Earth, both the moon and sun appear to be roughly the same size. </p>
<h3 id="P93B1K">7) I clicked this article accidentally and really just want a cool picture of the sun</h3>
<figure class="e-image">
<img alt=" " data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/8HMt8iGOEE8d5CKvHqgrgAZx2DA=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/6670127/446589main_fulldiskmulticolor-orig_full.jpg">
<cite>(NASA/Goddard/SDO AIA Team)</cite>
</figure>
<p id="jk5cFS">The image above <a href="http://www.nasa.gov/mission_pages/sdo/news/first-light.html"><strong>was taken</strong></a> by NASA’s Solar Dynamics Observatory, a spacecraft launched in 2010 to better understand the sun. Caption: "A full-disk multiwavelength extreme ultraviolet image of the sun taken March 30, 2010. False colors trace different gas temperatures. Reds are relatively cool (about 60,000 Kelvin, or 107,540 F); blues and greens are hotter (greater than 1 million Kelvin, or 1,799,540 F)."</p>
<p id="OOOSNB">In 2018, NASA will launch the <a href="https://www.nasa.gov/feature/goddard/2017/nasa-renames-solar-probe-mission-to-honor-pioneering-physicist-eugene-parker/">Parker Probe Plus</a>, a spacecraft that will come within 4 million miles of the surface of the sun (much closer than any spacecraft has been before). The goal is to study the sun’s atmosphere, weather, and magnetism, and figure out the mystery of why the sun’s corona (i.e., its atmosphere) <a href="https://www.theatlantic.com/science/archive/2017/05/its-lit/528594/">is much hotter than its surface</a>. Still, even several million miles away, the probe will have to withstand temperatures of 2,500 degrees Fahrenheit. </p>
<p id="iL3nie">It’s essential to understand the sun: It’s nothing to mess with.<a href="http://www.vox.com/2014/7/30/5951263/a-catastrophic-solar-storm-just-barely-missed-earth-in-2012"><strong> </strong><strong>Brad </strong><strong>Plumer </strong><strong>wrote</strong></a> about what happens when the sun erupts and sends space weather our way to wreak havoc on Earth. Happy solstice!</p>
https://www.vox.com/science-and-health/2017/6/19/15832952/summer-solstice-2017Brad PlumerBrian Resnick2017-06-01T14:31:32-04:002017-06-01T14:31:32-04:00What's at stake in Trump's looming decision on the Paris climate agreement
<figure>
<img alt="" src="https://cdn.vox-cdn.com/thumbor/rwyA59W3GK4bkPPUWJpeP72-LnA=/0x89:4070x3142/1310x983/cdn.vox-cdn.com/uploads/chorus_image/image/54314079/shutterstock_111362132.0.jpg" />
<figcaption>(Shutterstock)</figcaption>
</figure>
<p>Trump decided to pull the US out of the deal Thursday.</p> <p id="JlUqOt">Thursday at 3 pm, President Trump will announce whether or not the United States should stay in the <a href="http://www.vox.com/2015/12/12/9981020/paris-climate-deal">Paris climate deal</a> — the key international treaty to tackle global warming. </p>
<p id="av6aX3"><strong>Update: </strong><a href="https://www.vox.com/energy-and-environment/2017/6/1/15725510/trump-pulls-us-out-of-paris-climate-deal">President Trump pulls US out of the Paris climate agreement</a></p>
<p id="cQDLEj">The stakes are high: The Paris accord is a nonbinding treaty <a href="http://www.vox.com/2015/12/12/9981020/paris-climate-deal">that will depend on persuasion and cooperation</a> to succeed. Nearly every country on Earth has submitted a voluntary (if woefully inadequate) plan to restrain its greenhouse gas emissions, and the 2015 Paris deal created a formal process by which leaders could help one another ratchet up ambitions over time and push for stronger action at future meetings. If the world’s most powerful country steps back, that entire architecture could erode.</p>
<p id="C1ICQj">At the moment, <a href="https://www.nytimes.com/2017/05/31/climate/trump-quits-paris-climate-accord.html">many onlookers are betting</a> Trump will pull out of Paris. But some of Trump’s advisers, like Secretary of State Rex Tillerson, have warned of severe diplomatic blowback if America pulls out. And a variety of coal, oil, and gas companies <a href="https://www.axios.com/corporate-america-isnt-backing-trump-on-climate-2353777108.html">have urged</a> Trump to stay in, noting that there’s no real harm in sticking with a nonbinding treaty and that it’d be better to try to shape global climate negotiations from within.</p>
<p id="fBxMmP">During the campaign, Trump repeatedly vowed to pull out, and key advisers like Stephen Bannon <a href="https://www.nytimes.com/2017/04/18/us/politics/trump-advisers-paris-climate-accord.html?smprod=nytcore-iphone&smid=nytcore-iphone-share&_r=0">are lobbying him to follow through</a>. Scott Pruitt, the head of the Environmental Protection Agency and an ardent opponent of climate action, has <a href="https://www.washingtonpost.com/news/energy-environment/wp/2017/04/14/trumps-epa-chief-scott-pruitt-calls-for-an-exit-to-the-paris-climate-agreement/">argued</a> that the US should exit, calling it a “bad deal” for the country. </p>
<p id="UdV0vx">A decision either way, experts say, could have major implications for the future of climate talks — and, ultimately, the future of Earth’s climate itself.<strong> </strong>So let’s break down the options.</p>
<h3 id="kaxeWm">1) What happens if Trump decides to leave Paris?</h3>
<figure class="e-image">
<img alt="President Trump Departs White House En Route To Newport News, Virginia" data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/6_isPdYx112e-KvytkMshcxQtbk=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/8088275/647162502.jpg">
<cite>Photo by Alex Wong/Getty Images</cite>
<figcaption>Bye.</figcaption>
</figure>
<p id="i7iU8H">If the Bannon wing prevails, it would be easy enough for Trump to exit Paris. After all, the accord was never ratified by the Senate, and it is basically nonbinding.</p>
<p id="CW3vdS">To leave, the United States could invoke Paris’s formal withdrawal mechanism, which would technically take four years, although US officials could stop participating in any future talks immediately. (More radically, Trump could pull out of the underlying <a href="http://unfccc.int/2860.php">UN Framework Convention on Climate Change</a>, which would take just one year and signal that the US is abandoning <em>all </em>international efforts on climate change.)</p>
<p id="E3ertW">By far the biggest question at that point would be how other countries react. Leaders in <a href="https://www.washingtonpost.com/news/energy-environment/wp/2017/03/28/trumps-climate-rollback-raises-deep-questions-about-our-promises-to-the-rest-of-the-world/?utm_term=.5d3514c03c1b">Europe</a>, <a href="https://www.theguardian.com/world/2017/jan/19/chinas-xi-jinping-says-world-must-implement-paris-climate-deal">China</a>, and <a href="http://www.climatechangenews.com/2017/02/09/trump-wont-impact-indias-climate-drive-says-energy-minister/">India</a> have insisted they would carry on addressing climate change without the US. But the future arc of climate negotiations — in which countries try to ramp up their climate efforts in the hopes of limiting global warming below 2°C — might look very different.</p>
<p id="w3OuUh">China, the world’s largest emitter, would be poised to assume a dominant role in future talks, and its leaders have tended to argue for looser oversight and accountability mechanisms within the deal than the US has. “China has historically been a little more wary of strong international procedures and institutions,” David Victor, a political scientist with the University of California San Diego, told me recently. “You might see the treaty become more decentralized and less formalized over time.”</p>
<p id="IvViqa">A bigger concern is that if the US steps back, other countries could decide to scale back their own individual efforts to tackle global warming, says Andrew Light, a former senior climate negotiator at the State Department who is now at the World Resources Institute. “If the US pulls out altogether, the chances increase that developing countries like Brazil or India back away from their own commitments and say, ‘Why should we bother doing this if the world’s biggest historical emitter is completely out of the game now?’” he said. If that were to happen, the chances of avoiding severe global warming would start to look far more dire.</p>
<p id="QYsPnR">Of course, no one knows for sure what will happen. It’s possible that a US withdrawal could have a galvanizing effect on the rest of the world, and other governments would redouble their efforts to promote clean energy and curb emissions. Most nations still have a vested interest in avoiding drastic temperature increases. But there’s a real risk that momentum for stronger action would be blunted.</p>
<p id="DHxaEY">There’s also the prospect that the US <a href="http://www.wri.org/blog/2017/01/america-cant-afford-be-climate-loner">could face serious diplomatic repercussions for leaving</a>. Europe, China, and other countries could threaten to withhold cooperation on other issues the US cares about. In the most extreme scenario, other countries could threaten to impose carbon tariffs on the US, sparking a trade war. That’s why many Trump allies, like Sen. Bob Corker (R-TN), <a href="https://www.nytimes.com/2017/03/02/us/politics/climate-change-trump.html?_r=0">have argued</a> it may prove smarter to stay in.</p>
<h3 id="kY8zjG">2) What happens if Trump decides to stick with Paris?</h3>
<figure class="e-image">
<img alt=" " data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/wokQtJAgNIi1PQvzzjsuBC6i4gg=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/4160000/shutterstock_246312967.jpg">
<cite>(Shutterstock)</cite>
<figcaption>Trump wants to make coal great again, remember.</figcaption>
</figure>
<p id="nJB0Fr">Now imagine Trump decides to stay in the Paris accord. After the initial fanfare subsides, there’s the crucial question of whether the Trump administration would try to fulfill the Obama administration’s commitments under the deal — like the pledge to cut US greenhouse gas emissions 26 to 28 percent below 2005 levels by 2025.</p>
<p id="u0Pbqp">Odds are, they wouldn’t. Trump <a href="http://www.vox.com/energy-and-environment/2017/3/27/14922516/trump-executive-order-climate">has ordered the repeal</a> of many of Obama’s domestic climate policies, including the Clean Power Plan to curtail emissions from power plants, and various regulations around methane leaks from oil and gas operations. If those policies get dismantled, it will be nearly impossible to meet Obama’s pledge.</p>
<p id="sQmpeN">One possibility is that the Trump administration simply revises the US emissions goal downward — something they could probably get away with, <a href="https://unfccc.int/resource/docs/2015/cop21/eng/l09.pdf">though it would flout the spirit of the accord</a>, in which countries are supposed to enhance ambition over time. A move like that might, in turn, lead other countries to reconsider their own climate plans. If the United States isn’t taking its pledge seriously, why should they?</p>
<p id="tyj5O5">On top of that, a core part of the Paris deal involves the US pledging <a href="https://www.nytimes.com/2014/11/15/us/politics/obama-climate-change-fund-3-billion-announcement.html">$3 billion in aid to poorer countries</a> to help them expand clean energy and adapt to droughts, sea level rise, and other global warming calamities. The Obama administration already chipped in <a href="http://www.commondreams.org/news/2017/01/17/obama-sends-500-million-green-climate-fund-signaling-end-era">$1 billion</a>. But Republicans in Congress and the Trump administration have insisted they have no intention of delivering the rest.</p>
<p id="QVuYBf">Some experts think that Trump abandoning US commitments on aid could be nearly as damaging to international climate efforts as withdrawing from Paris altogether. “For the developing countries, this will be a sign that America is unreliable and that the benefits of staying engaged in climate negotiations are fleeting,” Victor <a href="http://e360.yale.edu/feature/what_donald_trump_win_means_for_global_climate_fight/3053/">wrote</a> in an essay in November.</p>
<p id="731dSR">That said, Light thinks this outcome could prove less disruptive than total withdrawal. Assume Trump stays in Paris, revises down the US pledge, and dismantles the Clean Power Plan. Even then, Light told me in March, there’d still be enough action from states that you could imagine the US making at least <em>some</em> headway on emissions, even if it’s far less than Obama promised. “And that would still leave the possibility that the US could rebound [on climate action] after one term of Trump,” he says. </p>
<h3 id="M4Ni7W">3) If Trump sticks with Paris, how might US negotiators shape future agreements?</h3>
<p id="WLtLQn">The 2015 Paris deal was only a first step in the long, grinding process of dealing with climate change — and a woefully inadequate step at that. If you add up all the country pledges worldwide, they don’t come close to keeping us below 2°C of global warming. They add up to <a href="http://www.wri.org/blog/2015/11/insider-why-are-indc-studies-reaching-different-temperature-estimates">a severe 3°C or more</a>, depending on which analysis you trust:</p>
<figure class="e-image">
<img alt=" " data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/k4pIZHx9oeSSxqiKyZrcjqlTgBs=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/7800799/INDC_Temp_Analysis.png">
<cite>(<a href="http://www.wri.org/blog/2015/11/insider-why-are-indc-studies-reaching-different-temperature-estimates">World Resources Institute</a>)</cite>
</figure>
<p id="96c9pI">The big hope with the Paris accord was that these individual national pledges <a href="http://www.vox.com/2015/12/12/9981020/paris-climate-deal">would be strengthened over time</a>, as countries cooperated and pushed each other to pursue deeper emissions cuts. So a key question here is what role US climate negotiators might play in this ratcheting process.</p>
<p id="YsU09W">For example: Over the next two years, negotiators are meeting at the UN to hash out rules around <a href="http://envirocenter.yale.edu/transparency-the-backbone-of-the-Paris-Agreement">how to review individual country pledges and policies</a>. This “transparency mechanism” could prove contentious. The Bush and Obama administrations had long pushed for strict, uniform transparency standards. China and other developing nations, by contrast, <a href="https://www.nytimes.com/2017/01/10/world/asia/china-wants-to-be-a-climate-change-watchdog-but-cant-yet-lead-by-example.html?_r=0">have in the past preferred</a> a “bifurcated” system that holds them to somewhat looser reporting requirements.</p>
<p id="KSKvtT">If Trump does stay in Paris, one question is whether the US will try to hold developing countries to the strictest transparency standards possible. And it’s worth asking how much leverage the US will really have if it’s <em>also</em> reneging on its emissions targets and aid promises elsewhere.</p>
<p id="upYJAL">This sounds like an obscure issue, but for many observers it’s critical. After all, climate change is a collective action problem. Countries are less likely to take the plunge and push for emissions cuts unless they know everyone else will jump with them. “To me, the essence of this agreement is what it can do to strengthen confidence that everyone’s doing their fair share, primarily through greater transparency,” says Elliot Diringer, executive vice president of the Center for Climate and Energy Solutions. “With greater confidence, everyone can do more. Weaker transparency rules would make it harder to strengthen confidence and ambition over time.” </p>
<p id="qDbZiO">Beyond transparency, the world’s nations are also supposed to formally take stock of their progress by 2018 and then submit new — and ideally stronger — NDCs by 2020. But this process of strengthening global pledges could get bogged down if the US is weakening its stated ambitions. It’s not hard to imagine India or China feeling less pressure to step up its efforts if the richest country on Earth is backsliding.</p>
<p id="2cyupr">It’s also possible that the Trump administration may push to reorient global climate talks in an entirely new direction — say, by placing a greater focus on working with China to promote <a href="http://www.vox.com/energy-and-environment/2017/4/12/15269628/carbon-capture-trump">carbon capture technology for coal and natural gas</a>. Some coal companies <a href="http://www.politico.com/story/2017/03/trump-paris-climate-pact-coal-companies-236730">have been urging</a> Trump to stay in the Paris deal to do exactly that.</p>
<p id="FpfSlK">“My guess is that the Trump administration would come out swinging against the idea of targets and regulations and instead argue that technology is the only way to solve this problem,” says Paul Bledsoe, a senior energy fellow at the Progressive Policy Institute. “They might argue that a crash program on carbon capture is the best way forward here.”</p>
<p id="tHpTcq">The larger point here is that the Paris climate deal isn’t guaranteed to succeed just because Trump sticks with the agreement. These nuances of what happens to a process that’s already well underway really do matter, and there are lots of ways the US could potentially change the deal — or weaken it — from within.</p>
<h3 id="udLrIq">Further reading:</h3>
<ul>
<li id="A8ye9P">Here’s <a href="http://www.vox.com/2015/12/12/9981020/paris-climate-deal">our primer on how the Paris climate deal works</a>. And <a href="http://www.vox.com/energy-and-environment/2017/3/23/15028480/roadmap-paris-climate-goals">here’s a scientific “roadmap”</a> showing what countries would actually need to do to meet the Paris goals. It’s daunting.</li>
<li id="Hgq5ae">Amy Harder of Axios <a href="https://www.axios.com/corporate-america-isnt-backing-trump-on-climate-2353777108.html">has a nice piece</a> on why many companies — including many coal companies — would prefer that Trump stick with the Paris climate deal.</li>
<li id="pVU1jl">Last fall, Neil Bhatiya and Tim Kovach <a href="http://grist.org/climate-energy/as-u-s-retreats-from-climate-leadership-china-steps-up-beware/">wrote much more</a> on what it would mean for China to take the lead on global climate policy — particularly in places like sub-Saharan Africa.</li>
<li id="Ho8wrK">How carbon capture <a href="http://www.vox.com/energy-and-environment/2017/4/12/15269628/carbon-capture-trump">could become a rare bright spot</a> on climate policy in the Trump era.</li>
</ul>
<p id="7P1lWD"></p>
https://www.vox.com/energy-and-environment/2017/4/18/15334258/trump-decision-paris-climate-dealBrad PlumerEliza Barclay2017-04-26T22:05:22-04:002017-04-26T22:05:22-04:00A Cold War theory for why scientists and the government have become so estranged
<figure>
<img alt="" src="https://cdn.vox-cdn.com/thumbor/I1EsGXmL33i743C3a140opNbyZU=/0x863:6188x5504/1310x983/cdn.vox-cdn.com/uploads/chorus_image/image/54459043/shutterstock_85297909.0.jpg" />
<figcaption>(Shutterstock)</figcaption>
</figure>
<p id="hh4PzD">These are dark times for science — or at least that’s what we keep hearing. President Trump is <a href="http://www.vox.com/science-and-health/2017/4/10/15177116/trump-nih-cuts-bad-idea-explained">pushing to slash research budgets</a>. Republicans in Congress are <a href="http://www.sciencemag.org/news/2017/03/lamar-smith-unbound-lays-out-political-strategy-climate-doubters-conference">harassing climate scientists</a>. Vaccine skeptics <a href="https://www.vox.com/science-and-health/2017/4/6/15160486/alex-jones-vaccines-autism-gates-fungus-health-conspiracy-theories">are clogging the airwaves</a>.</p>
<p id="HWU4Rh">Indeed, a big reason why tens of thousands of scientists <a href="http://www.vox.com/science-and-health/2017/4/19/14331168/science-march-protest-2017">rallied in cities around the country last weekend</a> was to counter what they see as “anti-science” attitudes taking hold in the United States — particularly in the US government. The March for Science, <a href="http://www.vox.com/science-and-health/2017/4/19/14331168/science-march-protest-2017">according to</a> organizer Jonathan Berman, a biology postdoc at the University of Texas Health Science Center, sent “the message that we need to have decisions being made based on a thoughtful evaluation of evidence.”</p>
<p id="zkuliw">But this raises the obvious question: Was the United States ever <em>pro-</em>science? Was there a golden age? And if so, why were things so different then? What’s changed?</p>
<p id="qOrLad">One of the more compelling responses I’ve seen to this question can be found in <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1540-6210.2007.00830.x/abstract">this 2008 paper</a> by W. Henry Lambright, a political scientist at the Maxwell School at Syracuse University. To simplify a bit, he argues that the glory days of US science were an artifact of the Cold War and the arms race against the Soviet Union. That era has long faded, but if scientists want to bring about a new golden age, they should study that history closely. Because it contains some valuable lessons about how politics drives public attitudes toward science — and not, as is often assumed, the other way around.</p>
<h3 id="lf2GGd">Politicians and scientists don’t naturally get along. The Cold War changed that.</h3>
<p id="2PCjyO">When I called Lambright to talk about the politics of science in America, he started off with a simple but provocative point: There’s no <em>inherent </em>reason why scientists and politicians should get along. “There’s just not a natural alignment between the two communities,” he said.</p>
<p id="ua4zth">Politicians, after all, have a very different job than scientists. At least ideally, scientists seek only to uncover objective truths about the world. They follow a strict methodology, explicitly meant to filter out values, biases, or preconceptions that might color their research. Politicians, by contrast, must grapple with conflicting values and interests. Adjudicating those disputes is the whole job, and most such disputes can’t be resolved by scientific facts alone. So, not surprisingly, the two communities don’t always see eye to eye.</p>
<p id="d4gDOB">During World War II, circumstances conspired to push the two camps into alignment. New science-based weapons — most famously the atomic bomb — aided the US in the war. Afterward, <a href="https://en.wikipedia.org/wiki/Vannevar_Bush">Vannevar Bush</a>, the wartime science leader, convinced Congress that all those technological advances they admired so much were made possible by foundational scientific research conducted long before the war. If policymakers wanted to see more such advances, they should fund more basic research and stay out of scientists’ way.</p>
<figure class="e-image">
<img alt=" " data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/RUnJbOuFxjQ92o-Rfmw2Gqdx10I=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/8380611/Vannevar_Bush_portrait.jpg">
<cite>(<a href="https://en.wikipedia.org/wiki/Vannevar_Bush#/media/File:Vannevar_Bush_portrait.jpg">Wikimedia Commons</a>)</cite>
<figcaption>Vannevar Bush, without whom no oversimplified history of American science is complete.</figcaption>
</figure>
<p id="VBmL1N">The relationship between government and scientists<strong> </strong>became even warmer during the Cold War, particularly after the Soviet Union launched the Sputnik satellite in 1957. Nervous US politicians turned to scientists to help them win the space race. The White House, for the first time, appointed a presidential science adviser. “Not only was there a huge increase in funding of basic research,” Lambright writes, “but also scientists held influence in the corridors of Washington power as never before.” </p>
<p id="3odQNt">It’s important to be clear on what motivated this warmer relationship. It was <em>not</em> politicians embracing the principles of objective scientific inquiry. Instead, both Democrats and Republicans had rallied around a larger common purpose — defeating the Soviet Union — and realized they needed scientists’ help in order to achieve that goal. Politics drove science’s golden age, not the other way around.</p>
<p id="Aq7QQH">But as the perceived Soviet threat subsided, the relationship between scientists and the US government began to fray. After the US sent people to the moon, NASA’s budget began to plummet. President Nixon abolished the White House’s scientific advisory positions in 1973 when scientists began opposing some of his policies (though Nixon also founded the Environmental Protection Agency; life is complicated). The Vietnam War eroded public trust in “experts.” Presidents Ford and Carter boosted federal spending on energy research to combat the oil crises of the 1970s — a new common threat — but once the price spikes abated, so did the funds. </p>
<p id="Fb1ow6">When the Cold War finally ended, scientists struggled to regain the prestige they once enjoyed in Washington. In 1993, Congress zeroed out funds for the <a href="https://en.wikipedia.org/wiki/Superconducting_Super_Collider">Superconducting Super Collider</a>, a groundbreaking but not intuitively useful particle accelerator — something that would have been unthinkable five years earlier. The Clinton administration only managed to salvage the International Space Station by justifying the mission in new geopolitical terms: It would usher in a new era of cooperation with Russia.</p>
<p id="S0E9W9">The idea “that progress in science and progress in society went hand in hand,” Lambright wrote in his paper, “was no longer accepted without question.” </p>
<p id="bEHPGb">At the same time, the scientific community was becoming increasingly embroiled in bitter political disputes. Some of the key research fields of the 1980s and ’90s — think climate change or stem cell research — conflicted sharply with the priorities of industry groups, social conservatives, and the Republican Party. Tensions boiled over under George W. Bush, whose administration clashed again and again with climate scientists, <a href="http://www.ucsusa.org/our-work/center-science-and-democracy/promoting-scientific-integrity/manipulation-of-global.html">going so far as to suppress warnings</a> from government researchers. </p>
<p id="RIAJ9M">When President Obama entered office, he tried to mend this rift and champion the interests of scientists from the White House. But that clearly didn’t solve the underlying structural issue — as evidenced by, well, the rise of Donald Trump. In recent decades, we have seen an upswing in political movements, particularly on the right, <a href="http://www.vox.com/policy-and-politics/2017/3/22/14762030/donald-trump-tribal-epistemology">eager to attack the scientific establishment</a>. Trump and his allies now feel comfortable openly shunning scientists and academics.</p>
<p id="hrAtp1">“The relationship between scientists and government is arguably at a low point today,” Lambright says. “But that’s the culmination of a trend that had been building for some time. The Cold War aligned the interests of science and most politicians. Once that was gone, it became harder and harder to keep that alignment going.”</p>
<h3 id="BEJp3V">Is there anything that can bring back science’s glory days?</h3>
<figure class="e-image">
<img alt="The Carrizo Plain National Monument" data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/a77EL6B8wRqlAPDbwwmYyvhhgmc=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/8380531/1320061.jpg">
<cite>Photo by David McNew/Getty Images</cite>
<figcaption>A hopeful metaphor, perhaps?</figcaption>
</figure>
<p id="nC4TFv">Today, of course, “science” has become a hotly contested partisan issue. It’s tempting to say that this is because liberals are “pro-science” and conservatives are “anti-science,” but things are a bit more nuanced than that. Hardly any conservatives are “anti-science” as a general stance. You won’t find a single Republican who disputes, say, the underlying physics that enables airplanes to fly. And public confidence in science writ large <a href="https://www.nap.edu/read/21798/chapter/4#12">has remained remarkably stable</a> for decades.</p>
<p id="bx1l7N">Instead, politicians are most often hostile toward particular scientific findings or communities that tell them things in conflict with their values and interests. The obvious example is climate change: If global warming really is a massive and urgent threat, then <a href="http://grist.org/climate-energy/what-would-wartime-mobilization-to-fight-climate-change-look-like/">it likely requires</a> big-government solutions that entail serious pain for GOP constituencies like coal miners or fossil fuel producers. That’s tough to accept, and triggers fierce skepticism. It’s notable that <a href="https://www.ncbi.nlm.nih.gov/pubmed/25347128">studies have found</a> conservatives are far more likely to endorse climate science if told there are ready technological fixes that won’t require extensive regulations.</p>
<p id="iRYt9f">For Democrats, on the other hand, tackling climate change fits in neatly with their values. The issue, as currently conceived, demands international cooperation, proactive government action, and aid to poorer communities. Liberals can embrace computer models of global warming without tossing aside everything they hold dear. (By contrast, left-leaning groups are more willing to dismiss scientific evidence when it does<em> </em>clash with their values — witness <a href="http://www.vox.com/2016/6/30/12066826/greenpeace-gmos-nobel-laureates">opposition to genetically modified foods</a>.) </p>
<p id="iluhud">Many climate scientists believe that if they can just get people to grasp the science of global warming, support for climate action will inevitably follow. But the history of the Cold War suggests that the reverse is closer to the mark — the politics needs to shift first, and <em>then</em> support for science will follow.</p>
<p id="QVmI63">“The type of extensive public support for science we’ve been discussing has historically been driven by something bigger, a common purpose,” says Lambright. “The Cold War was that common purpose. [In my 2008 paper,] I argued that climate change might one day play a similar role. You could imagine a time when it becomes so widely obvious and tangible that this is a threat that people feel they need scientists’ help deal with it.” </p>
<p id="ByKTBy">That certainly won’t be as straightforward as the Cold War was. Climate change is very different from Sputnik<em> </em>or a nuclear-armed rival<em>.</em> It’s not an easily visible threat that instills gut-level terror in people; polls show that most Americans <a href="https://www.nytimes.com/interactive/2017/03/21/climate/how-americans-think-about-climate-change-in-six-maps.html?_r=0">don’t think global warming will harm them personally</a>. It’s possible that future natural disasters will make climate change feel so urgent that large majorities demand drastic action. Or maybe changes in technology will lead the way — if renewable energy keeps growing and coal keeps dying, that could <a href="http://www.vox.com/energy-and-environment/2017/2/7/14533618/solar-jobs-coal">shift the underlying politics</a>.</p>
<p id="MxxD5t">“But that public consensus won’t solely be driven by scientists,” Lambright says. “It may have to be driven by external events, or by politicians who are leading on the issue. They’ll have to connect it to issues that people care about, like national security or economic security. And it may take some time.”</p>
<p id="KGWbA3">None of this is to let Trump off the hook. When <a href="https://www.vox.com/science-and-health/2017/3/28/15097628/sean-spicer-climate-change-hoax-trump">he implies that global warming is a hoax</a>, he is flatly and unambiguously wrong, he is doing real damage to public discourse, and scientists are correct to call him out on it. But it does suggest that bridging the broader divide that’s opened up between science and society will require far more than scientific education alone. </p>
<h3 id="Q2RB2m">Further reading:</h3>
<ul>
<li id="AOXvuv"><a href="http://www.vox.com/science-and-health/2017/4/19/14331168/science-march-protest-2017">The March on Science, explained</a></li>
<li id="IZOq1n">This Scientific American essay by Troy Campbell and Lauren Griffin <a href="https://blogs.scientificamerican.com/guest-blog/who-are-you-calling-anti-science/">is a nice explanation</a> of why attitudes toward science in the United States are far more complex than “pro-science” or “anti-science.”</li>
<li id="vDWS0A">Similarly, my colleague Julia Belluz <a href="http://www.vox.com/science-and-health/2017/4/20/15295822/alex-jones-fans-climate-change-vaccines-science">had a fascinating series</a> of interviews with fans of Alex Jones, a popular climate denier and vaccine skeptic on the radio. Their views on scientific issues were often far more nuanced than his.</li>
<li id="taen0t">Also read my colleague David Roberts <a href="http://www.vox.com/policy-and-politics/2017/3/22/14762030/donald-trump-tribal-epistemology">on the decline of trust in transpartisan institutions in the United States</a> — and the political consequences. I didn’t touch on that much in this piece, but it’s an important part of the story.</li>
</ul>
https://www.vox.com/science-and-health/2017/4/26/15373436/science-march-cold-warBrad Plumer2017-04-22T15:44:41-04:002017-04-22T15:44:41-04:007 things we've learned about Earth since the last Earth Day
<figure>
<img alt="earth" src="https://cdn.vox-cdn.com/thumbor/PqnyW2IXJ1FxxjMb_e8anpKQAg0=/0x340:2040x1870/1310x983/cdn.vox-cdn.com/uploads/chorus_image/image/54391243/North_America_from_low_orbiting_satellite_Suomi_NPP.0.jpg" />
<figcaption>Hey that’s us. | (NASA/NOAA/GSFC/Suomi NPP/VIIRS/Norman Kuring)</figcaption>
</figure>
<p id="d36cgq">This year’s Earth Day, April 22, will be dominated by <a href="http://www.vox.com/science-and-health/2017/4/19/14331168/science-march-earth-day-route-livestream-signs-speakers">March for Science rallies</a> taking place in Washington, DC, and dozens of other cities around the world. </p>
<p id="gn7pBI">But I also like to mark Earth Day by looking at some of the best new discoveries we've made about this breathing, seething, never-dull planet of ours — the only place in the universe where life is known to exist.</p>
<p id="v5yJiu">After all, a lot has changed since <a href="http://www.newyorker.com/magazine/2013/04/15/when-the-earth-moved?currentPage=all">the very first Earth Day</a> in 1970. Back then, America's most urgent environmental problems were smog and water pollution. In the years since, we've made <a href="https://www.epa.gov/clean-air-act-overview/progress-cleaning-air-and-improving-peoples-health">remarkable progress</a> mopping that up, only to confront fresh challenges like global warming and <a href="http://www.vox.com/2014/9/10/6131139/ocean-acidification-fastest-300-million-years">ocean acidification</a>. Even today, our knowledge of the Earth keeps evolving with each passing year. We've uncovered <a href="http://www.vox.com/2014/10/3/6901009/scientists-are-still-discovering-new-mountains-on-earth-mainly-on-the">new geological features</a>. We've brought endangered species <a href="http://wwf.panda.org/about_our_earth/teacher_resources/best_place_species/back_from_the_brink/">back from the brink of extinction</a>. We've transformed the atmosphere, for better and worse.</p>
<p id="Cr98Zr">So here's a list of some of the most surprising, hopeful, and worrisome things we've learned about Earth since the last Earth Day:</p>
<h3 id="XN24WA">1) Scientists (sort of) discovered an entire new continent: Zealandia!</h3>
<figure class="e-image">
<img alt=" " data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/JKM6aku-xo_jZbDXRKanzSASnyo=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/8386705/58a4840401fe586a018b4955_800.png">
<cite>(<a href="http://www.geosociety.org/gsatoday/archive/27/3/article/GSATG321A.1.htm">Mortimer et al., 2017</a>)</cite>
</figure>
<p id="FrHHNn">Okay, scientists didn’t discover New Zealand this year. It’s been sitting there for ages. But in February 2017, a team of researchers led by geologist Nick Mortimer <a href="http://www.geosociety.org/gsatoday/archive/27/3/article/GSATG321A.1.htm">published a paper</a> arguing that we should take a second look at this corner of the world. Because New Zealand isn’t just a tiny island nation. It’s arguably part of a unique 1.9-million-square-mile <em>continent</em>, not too different from North America or South America.</p>
<p id="AKSorP">Scientists have been collecting data on the slab of continental crust that surrounds New Zealand and New Caledonia for decades (much of which is underwater, of course). Over time, they’ve come to realize that this landmass has a distinctive geology and well-defined structure that separates it from the nearby continent of Australia. If you follow certain definitions of what constitutes a “continent,” Zealandia is its own thing.</p>
<p id="0kMfxv">This isn’t just a pedantic name change. The realization that Zealandia is actually an independent continent could help scientists better understand “the cohesion and breakup of continental crust," the authors write.</p>
<p id="hVETQT">But don’t go ripping up your geography textbooks just yet. There’s no official definition of “continent,” and scientists will likely be debating this for years. (Much like there are still <a href="https://www.vox.com/science-and-health/2017/3/25/15052084/make-pluto-planet-again">debates</a> over whether Pluto is a “planet.”) But it’s a good reminder that scientific discoveries don’t always have to entail new, never-before-seen objects. Sometimes they entail looking at familiar objects with fresh eyes.</p>
<h3 id="CMExp7">2) We've found dozens of new species — like this fluorescent frog...</h3>
<figure class="e-image">
<img alt=" " data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/EKxugwypAYc6Y_bMTzkrj6aIuPs=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/8386819/giphy_downsized_large.gif">
<cite>(<a href="http://www.nature.com/news/first-fluorescent-frog-found-1.21616">Nature</a>)</cite>
</figure>
<p id="aVMjHr">At this point, scientists have described about 1.5 million different species on the Earth. That <em>sounds</em> like a lot, but <a href="http://www.sciencemag.org/content/339/6118/413.short">estimates suggest</a> there are<em> </em>at least another 4 million species waiting to be documented. And we’re finding hundreds every year.</p>
<p id="NGaDSd">One nifty discovery came in March, when researchers <a href="http://www.nature.com/news/first-fluorescent-frog-found-1.21616">published a paper describing</a> the South American polka dot tree frog, which gives off a green-blue glow when placed under ultraviolet light. The frog doesn’t glow it the dark, exactly; instead it absorbs light at short wavelengths and re-emits it at longer wavelengths. (Glow-in-the-dark creatures, like fireflies, are known as <a href="https://en.wikipedia.org/wiki/Bioluminescence">bioluminescent</a>.) But only a few species can pull off this trick — and this is the first known fluorescent amphibian.</p>
<p id="8JdIIH">The past year has brought a wealth of other new species into view, too, from <a href="http://www.livescience.com/58644-big-furry-spider-discovered-in-cave.html">a cave-dwelling spider with red fangs</a> in Mexico to <a href="http://www.bbc.co.uk/news/science-environment-38366118">a ghostly octopod nicknamed “Casper”</a> on the ocean floor that, alas, may be under threat from deep-sea mining. Last September, a genetic analysis even revealed that <a href="https://www.nytimes.com/2016/09/09/science/a-quadruple-take-on-the-giraffe-its-four-species-not-one.html?_r=0">there are <em>four </em>distinct species of giraffe</a>, not just one, as previously thought.</p>
<h3 id="qirOWK">3) But we’re also losing species at an alarming rate</h3>
<figure class="e-image">
<img alt=" " data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/Q2ntMzgPHfL1io2ggyuHBmUzQ00=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/8366731/Screen_Shot_2017_04_18_at_5.47.08_PM.png">
<cite>Scott M. Denderson / <a href="http://www.aprilthegiraffe.com/">April the Giraffe</a></cite>
<figcaption>Giraffes aren’t gone yet, but they’re certainly in serious trouble.</figcaption>
</figure>
<p id="ZeplOp">Sadly, it can’t all be good news.</p>
<p id="XHGAKO">One of the reasons scientists are rushing to discover and describe as many species as they can is that <a href="http://www.vox.com/2014/6/11/5797636/the-world-is-facing-a-major-extinction-crisis-here-are-ways-to-avoid">we’re also <em>losing</em> a great deal of wildlife</a> at a shocking rate. As human civilization expands, and cities, farms, and mines proliferate, natural habitats and wilderness keep shrinking, driving many species to the brink. Global warming is also expected to drastically transform the historical range of a great many plants, birds, and animals — and many species may prove unable to adapt.</p>
<p id="WVEZyE">Last June, scientists <a href="https://www.theguardian.com/environment/2016/jun/14/first-case-emerges-of-mammal-species-wiped-out-by-human-induced-climate-change">announced</a> that the Bramble Cay melomys, a small rodent native to the Great Barrier Reef, has likely gone extinct as sea-level rise had inundated the small island it called home. If so, this could likely be the first known mammal to go extinct due to global warming (scientists have already blamed the changing climate for <a href="http://www.washingtonpost.com/wp-dyn/content/article/2006/01/11/AR2006011102121.html">wiping out a few frog species</a>).</p>
<p id="SimB3Y">Ecologists keep warning that many, many more extinctions could soon follow if we don’t act quickly to protect what wildlife remains. Giraffe populations <a href="https://www.vox.com/science-and-health/2016/12/8/13882626/giraffe-extinction-vulnerable-iucn-red-list">have declined 40 percent in the last 30 years</a>. More than <a href="https://www.vox.com/science-and-health/2017/1/23/14351224/primate-extinction-report-ahhh">half of all primate species</a> are sliding down the path toward non-existence. One enormous challenge of the 21st century is making sure that Earth’s rich biodiversity doesn’t just end up a distant memory, seen only in museums and old photos. (Here are <a href="http://www.vox.com/2014/6/11/5797636/the-world-is-facing-a-major-extinction-crisis-here-are-ways-to-avoid">a few ideas for slowing further extinctions</a>.)</p>
<h3 id="PyXMPA">4) The world’s oldest fossils may have been found in Canada — at least 3.7 billion years old</h3>
<figure class="e-image">
<img alt=" " data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/cO2pnYXY8PujkhtJlMpESnVFOFo=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/8386921/32341758634_e64e129f61_k.jpg">
<cite>(<a href="https://www.flickr.com/photos/uclnews/32341758634/">Matthew Dowd/Flickr</a>)</cite>
<figcaption>Haematite filament attached to a clump of iron in the lower right, from hydrothermal vent deposits in the Nuvvuagittuq Supracrustal Belt in Québec, Canada. These clumps of iron and filaments were microbial cells and are similar to modern microbes found in vent environments. </figcaption>
</figure>
<p id="TUCCIB">The history of human civilization can be condensed into less than 10,000 years, a blink of an eye in geological time. Earth, of course, has been around far, <em>far</em> longer than that, a timescale that’s often staggering to contemplate.</p>
<p id="mtr9xA">In March 2017, scientists with the University College of London <a href="https://www.ucl.ac.uk/news/news-articles/0217/010317-Worlds-oldest-fossils-unearthed/#fossils">announced</a> they had unearthed layers of quartz in Canada containing “microfossils” of bacteria that once lived underwater near hydrothermal vents, feasting on chemical reactions involving iron for their energy. The kicker? These rocks were thought to have formed between 3.7 and 4.3 <em>billion </em>years ago — which would make these the oldest fossils ever found.</p>
<p id="Hk7D7j">To put this in perspective, the Earth was thought to have formed <a href="https://en.wikipedia.org/wiki/Age_of_the_Earth">about 4.54 billion years ago</a>. The first oceans likely appeared <a href="https://en.wikipedia.org/wiki/Origin_of_water_on_Earth#Water_in_the_development_of_Earth">about 4.41 billion years ago</a>. Somehow, the earliest forms of life wriggled into existence not long after that. (By “not long,” of course, I’m talking hundreds of millions of years. No big deal.)</p>
<p id="FRcYPw">“Our discovery supports the idea that life emerged from hot, seafloor vents shortly after planet Earth formed,” lead author Matthew Dodd said when the results were announced. To be sure, measuring the exact dates of rocks this old is a tricky task, and scientists will likely debate their precise age for some time. Previously, the oldest known microfossils were thought to be embedded in 3.4-billion-year-old rocks found in Western Australia, though there’s dispute over whether those fossils were biological.</p>
<h3 id="tRyvv4">5) A new type of cloud was added to the official cloud atlas: Asperitas</h3>
<figure class="e-image">
<img alt=" " data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/yuYhQvweJifeS35U6YPJnAcpkfk=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/8386975/5858_main_altocumulus_stratiformis_opacus_asperitas_clouds.jpg">
<cite>(<a href="https://www.wmocloudatlas.org/clouds-supplementary-features-asperitas.html">World Meteorological Organization</a>)</cite>
<figcaption>The Asperitas cloud: characterized by localized waves in the cloud base, either smooth or dappled with smaller features, sometimes descending into sharp points, as if viewing a roughened sea surface from below. </figcaption>
</figure>
<p id="khZ22b">The <a href="http://www.wmocloudatlas.org">International Cloud Atlas</a> has been used to train meteorologists since the late 19th century. And there haven’t been any new clouds added in decades — which makes intuitive sense, since you’d assume we already know everything there is to know about the sky above us.</p>
<p id="2qqda6">But that all changed this year.</p>
<p id="eHfGag">Ever since 2006, the delightfully named Cloud Appreciation Society, a group of British weather enthusiasts, has been photographing and documenting an unusual type of turbulent cloud that can’t be found anywhere in the atlas. After much prodding and formal debate, the World Meteorological Organization agreed that this was indeed a distinct formation and added this new cloud, <a href="https://www.wmocloudatlas.org/clouds-supplementary-features-asperitas.html">dubbed the Asperitas</a>, to its taxonomy.</p>
<p id="rDFktP">“Asperitas,” the new edition of the atlas <a href="https://www.wmocloudatlas.org/clouds-supplementary-features-asperitas.html">says</a>, “is characterized by localized waves in the cloud base, either smooth or dappled with smaller features, sometimes descending into sharp points, as if viewing a roughened sea surface from below.” You can see more lovely pictures <a href="https://cloudappreciationsociety.org/asperitas-world-met-day/">here</a>.</p>
<p id="9TJQbc">The Cloud Appreciation Society, for its part, <a href="https://cloudappreciationsociety.org/asperitas-world-met-day/">hailed</a> the recognition of the Asperitas cloud as a triumph of citizen science, noting that the rise of smartphones has enabled non-scientists to document all sorts of phenomena in the world around us — and allow scientists to form a much richer picture of this planet of ours.</p>
<h3 id="CUCaXR">6) The Great Barrier Reef is in more trouble than we thought</h3>
<figure class="e-image">
<img alt="Photo of a healthy and unhealthy fire coral" data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/O9P99MQiITWHOi51ajuhmuU8G8Q=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/8365681/Pasted_image_at_2017_04_18_03_43_PM.png">
<cite>The Ocean Agency/XL Catlin Seaview Survey/Richard Vevers</cite>
<figcaption>Photo of a fire coral that experienced severe bleaching in the 2016 mass bleaching event</figcaption>
</figure>
<p id="nmHJTi">Coral reefs are often dubbed the rain forests of the ocean. They cover just 0.1 percent of the sea floor but are home to 25 percent of marine fish species. They sustain vital fishing industries, and they’re popular spots for divers and snorkelers.</p>
<p id="nG7Vjx">Unfortunately, these reefs are also <em>extremely</em> vulnerable to rising ocean temperatures and global warming. When the waters get too<em> </em>hot, the living coral polyps that build the reef expel the <a href="http://oceanservice.noaa.gov/education/kits/corals/coral02_zooxanthellae.html">zooxanthellae</a> that live in their hard skeletons and provide them with nutrients. Once that happens, the coral start suffering and take on a ghastly white color — known as “bleaching.” During severe bleaching events, many coral can die, which in turn hurts all the marine life that depend on the reef.</p>
<p id="SNRReN">Over the past year, Australia’s majestic Great Barrier Reef has been absolutely walloped by unusually warm ocean temperatures and <a href="http://www.vox.com/science-and-health/2017/4/18/15272634/catastrophic-coral-bleaching-great-barrier-reef-map">has suffered back-to-back bleaching events</a> — the first time that’s ever happened. Huge swathes of the reef <a href="http://www.vox.com/science-and-health/2016/11/29/13781434/great-barrier-reef-coral-dead">are now dying</a>. Worse, these bleaching events are expected to become increasingly common in the future if the planet keeps heating up, and the reef will struggle to recover. At a certain point, much of it will be gone for good.</p>
<p id="eQqJpc">Now, there are steps Australia can take to try to salvage its reef — or at least give it a fighting chance in the face of global warming. Humans can limit fertilizer and sewage runoff that further damage the coral. We can avoid overfishing key herbivores like the rabbitfish that nurture the reefs by clearing away excessive algae. </p>
<p id="Hsi1s9">But ultimately, limiting climate change is the crucial step if we don’t want to see these ecosystems vanish forever. "At 2°C [of global warming]," Mark Eakin, who runs NOAA's Coral Reef Watch program, <a href="http://www.vox.com/science-and-health/2016/11/29/13781434/great-barrier-reef-coral-dead">told me last year</a>, "we are likely to lose numerous species of coral and well over half of the world's coral reefs."</p>
<h3 id="EtfJ0y">7) But humans also showed that they can come together to tackle big environmental problems</h3>
<figure class="e-image">
<img alt="Giant Pandas Play After Snow In Hangzhou" data-mask-text="false" src="https://cdn.vox-cdn.com/thumbor/aJvf8jxhcg0ZyOX1WntOZvooxLA=/800x0/filters:no_upscale()/cdn.vox-cdn.com/uploads/chorus_asset/file/8387087/506189554.jpg">
<cite>Photo by VCG/VCG via Getty Images</cite>
<figcaption>Giant pandas, coming back from the brink of extinction.</figcaption>
</figure>
<p id="7glOjn">I'm going to end this list on a more hopeful note. Humans have done a lot of damage to this planet and the other species on it, it’s true. But we’ve also shown a remarkable ability to <em>save</em> other species, to restore ecosystems, to blunt the harm we’ve caused.</p>
<p id="Es2gaN">Over the past year, we’ve brought the giant panda <a href="https://www.worldwildlife.org/stories/giant-panda-no-longer-endangered">back from the brink of extinction</a>, thanks to concerted conservation efforts. Scientists <a href="http://www.abc.net.au/news/2016-08-31/healthy-tasmanian-devils-released-to-test-vaccine-efficacy/7802672">are developing a vaccine</a> to protect the endangered Tasmanian devil from dying in the face of a lethal facial tumor disease. Just this spring, ecologists at the Smithsonian Institute <a href="https://nationalzoo.si.edu/conservation-ecology-center/news/scimitar-horned-oryx-calves-born-wild">announced</a> that the scimitar-horned oryx, a sort of antelope once extinct in the wild, had been reintroduced in Chad and was now breeding again.</p>
<p id="ESTrOi">“Although some of these achievements may seem limited in scope,” wrote Andrew Balmford and Nancy Knowlton in <a href="http://science.sciencemag.org/content/356/6335/225">a recent <em>Science </em>essay</a><em>,</em> “much of conservation depends on the accumulation of small-scale advances across the planet.”</p>
<p id="o9oJM2">Humans have banded together to do much bigger things too, the authors note. More than 5 percent of the world’s oceans <a href="http://www.un.org/apps/news/story.asp?NewsID=55798#.WPqvdrvyu2w">are now Marine Protected Areas</a>, up from 1 percent a decade ago. The nations of the world <a href="http://www.vox.com/energy-and-environment/2017/3/21/14988436/global-coal-boom-decline">are making remarkable progress</a> in bolstering clean energy and moving away from coal, a key driver of global warming. Yes, these efforts are still insufficient in the face of some of the massive environmental problems we’re facing. But it’s hardly all doom and gloom. </p>
<p id="4XQIrJ">Just as humans are capable of making astounding discoveries about this planet, we’re capable of altering its trajectory. The idea behind the original Earth Day was that we can harness human ingenuity to alter that trajectory for the better. There are certainly signs of that, if you know where to look.</p>
<p id="lJ7lbc"><strong>Further reading:</strong> <a href="http://www.vox.com/2015/4/7/8352381/anthropocene-NASA-images">15 before-and-after images that show how we're transforming the planet</a></p>
https://www.vox.com/science-and-health/2017/4/22/15378240/earth-day-2017Brad Plumer