08 Oct 2013:
Eighty Percent of Ecosystems
Vulnerable to Climate Change, Study Finds
Climate change could significantly transform up to 86 percent of the planet's land ecosystems under worst-case global warming scenarios, according to researchers at Germany's Potsdam Institute for Climate Impact Research
. That estimate is based on a 4 to 5 degree C temperature increase by the year 2100 — a scenario that is plausible given many nations' reluctance to enact greenhouse gas emissions limits, the researchers say. Even if global temperatures are kept to 2 degrees C above preindustrial levels, 20 percent of natural land ecosystems are at risk of moderate or major changes, especially high-altitude and high-latitude regions. Such changes could include boreal forests being transformed into temperate savannas, trees growing in thawed Arctic tundra, or even a dieback of some of the world's tropical forests. "Essentially, we would be leaving the world as we know it," says Sebastian Ostberg, who led the research. "The findings clearly demonstrate that there is a large difference in the risk of global ecosystem change under a scenario of no climate change mitigation compared to one of ambitious mitigation," he added. A second study
by Potsdam Institute researchers predicts that climate-related land changes could put 500 million people worldwide at risk for water scarcity.