I stumbled across this book looking for information on dirty bombs (don't ask). It turns out the last half is devoted to explaining climate change and policy implications. The book is well written and the discussion is very good, technically accurate (as far as I can tell), and well balanced in that Muller sticks to facts and a strict interpretation of the IPCC reports. (Muller is a physics prof. at Cal-Berkeley and past recipient of a MacArthur Foundation "genius" grant.)
Anyway, I recommend it highly:
Physics for Future Presidents, Richard A. Muller, 2008, W.W. Norton, 380 pp.