Climate Change/Science/Ancient Climate
This section deals with climate and its variability on very long, geologic, time scales. These time scales are greater than centuries, and there are important millennial and multi-millennial signals in the so-called paleo record. Some research focuses exclusively on ancient climates; such work is often referred to as paleoclimatology (also paleoceanography or paleogeography).
While a review of all relevant topics is beyond the scope of this Wikibook, some discussion of paleoclimate can shed light on the natural variability of the climate system. This includes not-so-distant climates, like that of the "little ice age," and also the global-scale oscillations known as ice ages. At time scales even longer than ice ages (105 years), there are large variations of climate associated more with geological processes than atmospheric and oceanic. While intensely interesting, these climates will be ignored here.