Higher temperatures: Every continent has warmed substantially since the 1950s. There are more hot days and fewer cold days, on average, and the hot days are hotter.
Heavier storms: The world’s atmosphere can hold more moisture as it warms. As a result, the overall number of heavier storms has likely increased since midcentury, particularly in North America and Europe (though there’s plenty of regional variation).
Heat waves: Heat waves have likely become longer and more frequent around the world over the past 50 years, particularly in Europe, Asia, and Australia.
Shrinking sea ice: The extent of sea ice in the Arctic has shrunk since 1979, by between 3.5 percent and 4.1 percent per decade, on average. Summer sea ice has dwindled even more rapidly:
Shrinking glaciers: Glaciers around the world have, on average, been losing ice since the 1970s. In some areas, that is reducing the amount of available freshwater.
Sea-level rise: Global sea levels rose 25 centimeters (9.8 inches) in the 19th and 20th centuries, after 2,000 years of relatively little change. The pace of sea-level rise has continued to increase in recent decades. 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.
Food supply: 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 found that global warming was currently benefiting crops in some high-latitude areas, but that negative effects were becoming increasingly common worldwide.
Shifting species: Many land and marine species have had to shifttheir geographic ranges in response to warmer temperatures. So far, only a few extinctions have been linked to global warming, such as certain frog species in Central America.
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:
Droughts have become more frequent and more intense 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 less frequent. There’s still a fair bit of debate on how global warming has affected droughts so far.
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. And there doesn’t yet seem to be any clear trend for tropical cyclones worldwide.