14-04-2010: What caused Earth’s temperature variations during the last 800,000 years?

Climate fluctuations during the ice ages were caused by changes in insolation, greenhouse gases, ice sheets, atmospheric dust loading, and more. This study addresses the relative importance of these mechanisms and feedbacks on the total glacial-interglacial climate shifts. It strongly suggests that many, and probably all, climate feedbacks are not constant in time, with their strength depending on the climate state. The best estimate, based on paleoclimate data and forcings for the last glacial maximum, for present-day climate sensitivity ranges between 1.4 and 5.2 K, with a best estimate of 2.4 K.