NASA scientist calls for 'full court press' to save ice caps
Dramatic action is needed to save the Arctic and Antarctic ice shelves from global warming, a NASA researcher says.
"We probably need a full court press on both CO2 emission rates and non-CO2 forcings to avoid tipping points and save Arctic sea ice and the West Antarctic ice sheet," James Hansen, from the NASA Goddard Institute for Space Studies, said in a release.
Another decade of "business-as-usual"will make it difficult to avoid the change, he added.
His comments were made just a day after NASA administrator Michael Griffintold U.S. National Public Radio that "I have no doubt that global — that a trend of global warming exists. I am not sure that it is fair to say that it is a problem we must wrestle with."
Hansen and co-researcher Makiko Sato from the Columbia University Earth Institute concluded that global warming has driven the Earth's climate near to "critical tipping points," which occur when a small temperature increase triggers an effect that gets worse as it feeds on itself.
An increase of one degreeabove the global temperature in 2000 "is likely to be dangerous," because it will push the climate to atipping point.
Hansen and Sato identified the Arctic and Antarctic ice as two vulnerable areas in a study based on simulations published Thursday in Atmospheric Chemistry and Physics. They acknowledged that identifying"dangerous" effects is partly subjective.
The studyfound global warming of 0.6degrees in the past 30 years was mainly caused by greenhouse gases made by humans, and a "moderate" additional rise"is likely to set in motion disintegration of the West Antarctic ice sheet and Arctic sea ice."
Highertemperatures melt ice, exposing darker surfacesthat absorb more heat and speed the ice sheet breakup. As oceans warm,the ice shelves that otherwiseslow ice flows melt more quickly, so the whole process speeds up.
Freshwater sources and species habitat are also threatened, the authors said.
Atmospheric carbon dioxide has increased from the pre-industrial level of 280 parts per million (ppm) to 383 ppm today,and is rising by abouttwo ppm per year.Sato said"CO2 exceeding 450 ppm is almost surely dangerous, and the ceiling may be even lower."