Jim Snook 
Ice Age Extinction 

Global warming seen from the other side: by the end of the last ice age, the earth had lost most of its large animal species and most of its humans. In a novel approach the author argues that the main cause of this catastrophic extinction was a drastic reduction in atmospheric carbon dioxide, due to the long period of cold, and he backs up his theory with scientific explanations given in clear language for the general reader. Many books on the causes of extinction have been published over the last forty years, but all looked at other causes and none examined the role of low atmospheric carbon dioxide.