Figure 2 Variations in regional surface temperatures for the last 18,000 years, estimated from a variety of sources. Shown are changes in C, from the value for 1900. Compiled by R. S. Bradley and J. A. Eddy based on J. T. Houghton et al., Climate Change: The IPCC Assessment, Cambridge University Press, Cambridge, 1990 and published in EarthQuest, vol 5, no 1, 1991.