Climate and the orbital parameters of the Earth

The discovery of glacial ages in the 19th century triggered the first scientific questions on the evolution of climate through time, and thus corresponds to the dawn of palaeoclimatology. Since then, scientists have attempted to reconstruct past climatic changes and to understand their physical basis. Two competing theories have been suggested to explain the sequence of glacial–interglacial epochs: either the variations of the Earth orbital elements, or the atmospheric composition in carbon dioxide. If the astronomical theory has been largely confirmed since the last 30 years, a physical modeling of the climatic processes at work is still in its infancy. Besides, the most recent results of palaeoclimatology are clearly demonstrating that, more than never, a synthesis of these two old hypotheses is needed.