climate change booklist from Mitchell Thomashow
Tim Flannery's The WeatherMakers is an outstanding, compellingly written introduction to the biospheric changes that are already underway. This is the best biodiversity oriented introduction to the challenge of climate change.
William F Ruddiman - Plows, Plagues and Petroleum - suggests that significant climate change commenced during the agricultural era, and that by inadvertantly warming the planet we may have avoided global cooling! Ruddiman neatly incorporates climate change science with global environmental history. It's a smooth read, too.
For a first-hand journalist's account, read Elizabeth Kolbert's Field Notes From A Catastrophe.
and two older books:
Climate change makes much more sense when you understand the earth's biogeochemistry. Read Tyler Volk's imaginative, well crafted book Gaia's Body for a fine introduction.
Thinking about paleoecology helps, too. Read E C Pielou After the Ice Age for an accessible naturalist-oriented approach to climate and biogeography, with a focus on the return of life to glaciated North America.