In a video, noted scientists debate the connections between ancient climate changes and the emergence of modern human traits. (scientificamerican.com)
But experts say the pattern of Eocene rainfall and rivers, while perhaps important for ancient climate changes, may not help understand future climate changes. (sciencemag.org)
Scientific analysis of past climates shows that greenhouse gasses, principally CO2, have controlled most ancient climate changes. (skepticalscience.com)