Tipping points in the climate system

Summary

A tipping point is a threshold beyond which a small further push causes a large change of state of a part of the climate. The change is often abrupt and self-sustaining, and it may be hard or impossible to reverse. Proposed examples include the collapse of the Atlantic overturning circulation and the loss of the Greenland and West Antarctic ice sheets. Another is the dieback of the Amazon rainforest. Mathematically, the simplest mechanism is a saddle-node bifurcation at which a stable state disappears, as in the Stommel box model and the Budyko–Sellers model. Theory predicts warning signs before such a bifurcation, such as slower recovery from small disturbances.