So far we have dissected the anatomy of climate change (Figure 6.1) on a timescale of 103-106 years. Long records of proxy climate data from the oceans and continents show not only that there were many more than the four ice ages originally postulated in the nineteenth century, but that the pattern of climate change is not a simple one of alternating cold and warm episodes. During the last million years, global climate was for most of the time somewhere in-between the extreme cold of glacial maxima and interglacial warmth (Figure 6.1(e)), and present day interglacial conditions only existed for about ten per cent of this time.