Other types of feedbacks could potentially slow the warming.
The loss of Arctic sea ice won't be the last abrupt change in earth's climate, because of feedbacks.
It posits the existence of feedbacks at the global level which, so far, have served to keep the earth's surface habitable within a tolerable range, despite significant external changes, including changes in the radiation from the sun.
However, the inclusion of feedbacks due to changes in the natural land and ocean carbon sinks has the advantage of more directly linking man-made greenhouse gas emissions with the ensuing global temperature increase.
The crushing size of that ice sheet, the Laurentide, which stretched over some five million square miles, was the result of feedbacks, more or less analogous to those now being studied in the Arctic, only operating in reverse.
"One of the really fun things that we're doing now is understanding how the type of feedbacks in these groups is like the ones in the brain that allows humans to make decisions," Dr. Couzin said.
These types of feedbacks refer to self-reinforcing process which, once human-induced emissions create a change in a particular eco-system, lead to further changes beyond the initial human forcing as different parts of the system continue to respond.
It walks readers through the basics of the energy cycle on the planet before embarking on a deeper consideration of feedbacks involving clouds and other parts of the "earth system," as scientists call it.
Whether the past was naturally warmer or cooler than recently, and whether the changes were faster or slower than recently, are of great interest to climate scientists in learning how the climate system works, including the strength of feedbacks.
Although no one knows exactly how this happened, it seems, like so many climate events, to have been a function of feedbacks — the less rain the continent got, the less vegetation there was to retain water, and so on until, finally, the system just flipped.
This implies that the amount of feedbacks is rather limited.
