Earth's climate close to tipping point

GREENBELT, Md., June 4 (UPI) -- U.S. scientists say human-made greenhouse gases have brought Earth's climate close to critical tipping points, with potentially dangerous consequences.

National Aeronautics and Space Administration scientists, along with researchers from Columbia University's Earth Institute, reached that conclusion from a combination of climate models, satellite data and paleoclimate records.

Tipping points can occur when the climate reaches a state such that strong amplifying feedbacks are activated by only moderate additional warming. The study found only moderate additional climate forcing is likely to set in motion disintegration of the West Antarctic ice sheet and Arctic sea ice.

The study's lead author, James Hansen of NASA Goddard Institute for Space Studies IN Greenbelt, Md., said, "If global emissions of carbon dioxide continue to rise at the rate of the past decade, this research shows there will be disastrous effects, including increasingly rapid sea level rise, increased frequency of droughts and floods, and increased stress on wildlife and plants due to rapidly shifting climate zones."

The complex research appears in the current issue of Atmospheric Chemistry and Physics.