Paleoclimate

http://en.wikipedia.org/wiki/File:All_palaeotemps.png

CO2 as a primary driver of Phanerozoic climate (2004) Royer, et al

Trends, Rhythms, and Aberrations in Global Climate 65 Ma to Present (27 April 2001) James Zachos, Mark Pagani, Lisa Sloan, Ellen Thomas, and Katharina Billups
Science 292 (5517), 686. [DOI: 10.1126/science.1059412]