I’m reading a couple of interesting books on climate at the moment, both by David Archer, who is professor of geophysical sciences at the University of Chicago. One of them, “The Global Carbon Cycle” published in 2010 by Princeton University Press, is a bit technical for me (lots of chemistry) but I’m getting the overall picture. The other, “The Long Thaw: How Humans are Changing the Next 100,000 years of the Earth’s Climate”, published in 2009 also by Princeton, is more popular; it seems to be making the same points but without all the technical chemistry.+Here are a couple of passages from p. 25 of “The Long Thaw”: “No one is attempting to forecast the particular weather to expect on a particular day a century from now. Individual fluctuations of weather are chaotic, but the time-averaged weather, called climate is not.” “Perhaps this is as good a definition of the word ‘climate’ as any; those aspects of the weather that can be predicted far in the future, in spite of the fact that the weather is chaotic.”+That’s just a small point, but some of the people who don’t understand about global climate change don’t understand some of these concepts. From time to time I come across people who say that because the weather is chaotic you can’t predict climate. Those people don’t understand chaos theory.