Charles Krupa / AP

Substantial portions of Earth are increasingly covered in vegetation in response to increases in carbon dioxide in the atmosphere and changes in land use, a new study finds. But the increases have significantly different impacts on the planet's climate depending on whether it's happening in boreal forests in places like Canada and the Arctic or arid regions like the sub-tropics in and around the Horn of Africa.

What it means: Climate models are constantly being refined to reflect advances in science and improvements in data sets. This new study on leaf abundance will help predict impacts more accurately at the regional level.

For example: Increases in leaf abundance in boreal forests causes a significant increase in global warming, because that part of the Earth grows darker and doesn't reflect as much sunlight back into space. This sort of greening that reduces surface albedo could be adding an additional 10% to warming. However, in arid regions, this increase in leafy vegetation may actually be slowing the effects of global warming by up to 14% through a process called transpiration, in which water evaporates from leaves and enters the atmosphere.

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Illustration: Sarah Grillo/Axios

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