Richard Alley gave a well reviewed Bjerknes Lecture at the December AGU meetings in San Francisco, in which clearly and interestingly explains the paleo-climatic evidence of how CO2 is a key part of the Earth’s climate regulatory system.  Lots of interesting research, some of it quite recent, is synthesized clearly.

His talk The Biggest Control Knob: Carbon Dioxide in Earth’s Climate History is available on the AGU meeting website.

Richard Alley, is a professor of geosciences, at Penn State University and author of the popular science paeleo-climatology book The Two-Mile Time Machine: Ice Cores, Abrupt Climate Change, and Our Future.