Milankovitch Theory and Climate

Abstract. Among the longest astrophysical and detailed seasonal cycle) is considered for the astronomical cycles that might influence climate different latitudes, their long-term deviations (and even among all forcing mechanisms external to can be as large as 13 % of the long-term average, the climatic system itself), only those involving and sometimes considerable changes between extreme variations in the elements of the Earth's orbit values can occur in less than 10,000 years. Mod-have been found to be significantly related to the els of different categories of complexity, from long-term climatic data deduced from the geologi- conceptual ones to three-dimensional atmospheric cal record. The aim of the astronomical theory of general circulation models and two-dimensional paleoclimates, a particular version of which being time-dependent models of the whole climate system, due to Milankovitch, is to study this relationship have now been astronomically forced in order to between insolation and climate at the global test the physical reality of the astronomical scale. It comprises four different parts: the theory. The output of most recent modeling ef-orbital elements, the insolation, the climate forts compares favorably with data of the past model, and the geological data. In the nineteenth 400,000 years. Accordingly, the model predictions century, Croll and Pilgrim stressed the importance for the next 100,000 years are used as a basis fo