ABSTRACT
Explaining these changes in the Earth’s climate is not an easy task since there are very many factors that infl uence our atmosphere and make it dynamic on several diff erent scales. Some important climatic change theories have focused on variations in the amount of solar radiation received by the atmosphere. A composite sequence of these variations due to perturbations in the Earth’s orbit around the sun was calculated in the early years of the twentieth century by a Serbian mathematician named Milankovitch. ree types of variation, operating with diff erent periodicities were identifi ed:
1 orbital eccentricity with a periodicity of 100,000 years; 2 axial tilt or obliquity with a periodicity of 41,000 years; 3 precession of the equinoxes with a periodicity of about 21,000 years.
