[QUOTE="Simian"] According to wikipedia there are 23,000, 26,000, 41,000, 100,000, and 400,000 year cycles, with the 100,000 year cycle being the most (or perhaps only) one that has particular effect on climate. We are (apparently) 50,000 years away from the next ice age as predicted by the Milankovitch theory. A theory which doesn't actually fit the ice age data very well. The 'mini ice age' was not a global phenomenon, i.e. it was local cooling more akin to the recent couple of cold winters we've had where changes in the distribution of heat occur, rather than in the amount. [/QUOTE] Wasn't it caused by Toba erupting or something ?