Dangerous warming

Group: Melting Arctic a growing threat

Feedback can accelerate changes in the system, they said. For example, the white sea ice reflects solar radiation back into space, but as the ice melts the dark water will absorb some of the light, warming and melting more ice.

The scientists said they did not see any natural mechanism that could stop the loss of ice.

"I think probably the biggest surprise of the meeting was that no one could envision any interaction between the components that would act naturally to stop the trajectory to the new system," Overpeck said.