How climate change will reshape ecosystems
If climate change continues on its current course, nearly every ecosystem on Earth will be completely transformed, creating a world almost unrecognizable compared with the one we live in today. That’s the conclusion of a major new international study that sought to shed light on the future by looking at the past, reports TheAtlantic.com. The researchers examined fossil and temperature records from the peak of the last Ice Age, about 20,000 years ago, to the year 1800. Global temperatures rose 4 to 7 degrees Celsius over that period, and the resulting changes were extreme: Sea levels rose by nearly 400 feet, forests grew on what was once ice-covered ground, and savanna turned to desert. To look ahead, the researchers examined how ecosystems would fare under four possible climate-change scenarios over the coming century. In the most optimistic case—in which global temperatures rise only 1 degree Celsius— the chances of large-scale ecosystem change remain low. But in the other three, including the “business as usual” scenario of 4-degree temperature increases by 2100, the world would be completely altered: Oak forests would turn into grasslands; evergreen woods would become deciduous. The findings, says study co-author Jonathan Overpeck, a climate scientist at the University of Michigan, “provide yet another wake-up call that we need to act now to move rapidly toward an emission-free global economy.”