Ice core, deep sea sediment, loess, stalagmites, lake sediment, all these proxies record the ancient climatic variation which have cycles of 100 ka, 41 ka, 20 ka, and Millennium. For the age interval 2.45 Ma BP to 1.6 Ma BP, cycles of 166 ka and 333 ka were obvious; 1.8 to 0.8 Ma BP, cycle of 41 ka took place as the primary period of ancient climate. The 100 ka cycle has dominated from 0.8 Ma BP to the present.
The mechanism of globally existing 100 ka cycle is attributed to inclination of Earth' s orbital plane or to accretion rates of meteorites and cosmic dust on Earth, while the circulation of deep-sea brine model can interpret the regional millennial period in the North Atlantic Ocean area. New discoveries and various models show that long periodic (low frequency) climatic change seems to be caused by mutual effect of extraterrestrial celestial bodies, shorter periodic (high frequency) one are the result of restriction among various systems within Earth. Many climatic change-driven mechanism are unknown and therefore, data collation and to study cooperatively and comparatively through out the whole world are the key points in the future.