Each year, the world's cars, trucks, power plants, and factories emit billions of tons of extra carbon dioxide into the atmosphere. But where does it all go?
This mesmerizing new animation from NASA simulates a year in the life of all the carbon dioxide — the main gas responsible for global warming — in the atmosphere. The data is from 2006 and yes, it looks like a lava lamp:
More precisely, what this video shows is concentrations of carbon dioxide, ranging from 375 parts per million (in blue) to 385 ppm (in red) up to 395 ppm (in pink). It also shows carbon monoxide in white.
As you can see, carbon dioxide spreads fairly rapidly around the world. That's a key reason why global warming can't be solved by just a few countries acting alone. Emissions from one region don't just affect that region. Carbon-dioxide emissions from the eastern United States get picked up by westerly winds and are carried quickly across the Atlantic. Emissions in China travel far and wide.
As that extra carbon dioxide mixes in the atmosphere, it traps extra heat on the Earth's surface and warms up the planet. On the whole, carbon-dioxide concentrations in the atmosphere have risen from 270 parts per million before the Industrial Revolution to nearly 400 ppm today, largely because we've been burning fossil fuels. As that number keeps rising, it will raise surface temperatures, melt land ice, hike sea levels, and bring all sorts of other changes to Earth's climate.
This NASA simulation is the first to show in such precise detail precisely how carbon-dioxide moves around the atmosphere. Among other things, it reveals a significant difference in concentrations over the Northern and Southern Hemisphere. It also shows how plant growth in the spring absorbs some of the carbon-dioxide in the air (and then releases it again in the winter). It also revealed some surprises — like how the Himalayas block carbon dioxide from China's industrial base from traveling west:
The visualization was created by NASA's GEOS-5 computer model, which took data on atmospheric conditions and greenhouse-gas emissions and simulated the behavior of the Earth's atmosphere between 2005 and 2007. The hope is that this more precise modeling can help scientists better understand exactly where all the carbon-dioxide we're pumping out goes — and how it's warming the planet.
How humans have disrupted the carbon cycle
Before the Industrial Revolution, the Earth's atmosphere already contained some carbon-dioxide — roughly 270 parts per million. (That's why the planet wasn't a frigid wasteland.) Overall CO2 levels were regulated by the natural carbon cycle: Animals would breathe out carbon-dioxide, plants would absorb it to convert sunlight to energy, and the oceans and soils would both absorb and emit CO2.
But human activities significantly altered that cycle. As we began burning oil, gas, and coal for energy, we released additional carbon-dioxide into the atmosphere that was previously buried deep underground.
So far, about one quarter of that extra carbon-dioxide has been absorbed by the oceans (which in turn became more acidic), one quarter by soils and plants (which are bolstered by the extra CO2). The other half made it into the atmosphere, contributing to global warming:
Carbon-dioxide concentrations in the atmosphere are now hovering near 400 parts per million — levels have never been that high since human civilization has been around. Concentrations actually tick up and down a bit each year as plants in the Northern Hemisphere bloom in the spring and then lose their leaves in the winter. But they've been moving upward overall:
And if fossil-fuel use continues to grow at its historical rate, carbon-dioxide concentrations are projected to hit 1,000 parts per million by the end of the century — creating a drastically differently planet. Scientists have warned that that much carbon dioxide is likely to lead to sharp temperature increases, rapidly acidifying oceans, several feet of sea-level rises, and mass extinctions.
Even if we were to stop emitting carbon-dioxide tomorrow, atmospheric concentrations would remain elevated for centuries — so, on any reasonable time scale, the changes that we're making to the Earth's climate system are irreversible. The only question is how much we'll choose to change it.
-- Carbon-dioxide levels in the atmosphere rose at a record pace in 2013.
-- The oceans are acidifying at the fastest pace in 300 million years. How bad could it get?