It is not possible to understand the present or future climate unless scientists can account for the enormous and rapid cycles of glaciation that have taken place over the last million years, and which are expected to continue into the future. A great deal has happened in the theory of the ice ages over the last decade, and it is now widley accepted that ice ages are driven by changes in the Earth's orbit. The study of ice ages is very inter-disciplinary, covering geology, physics, glaciology, oceanography, atmospheric science, planetary orbit calculations astrophysics and statistics.