Abstract
The time-dependent properties of the Fokker–Planck equation corresponding to a zero-dimensional climate model, showing bistable behavior and subject to a weak external periodic forcing are analyzed. Conditions under which the response is amplified are found analytically. In this way the possibility of transitions between climatic states is established. The results are illustrated by the 100,000-yr periodicity of the eccentricity of the earth's orbit, in connection with glaciation cycles.