I have recently become quite concerned about ice ages and the dangers they pose to humans on our planet -- and indeed to most of terrestrial ecology. I must confess I never much worried about the supposed dangers of global warming -- even if we could rely on the predictions of IPCC climate models.  In fact, they seem to be failing miserably, as judged by the ongoing pause in GW -- while atmospheric levels of anthropogenic CO2  and other greenhouse gases continue to increase.  It seems that our climate is mainly controlled by natural forcings, like solar activity and atmosphere-ocean oscillations that are not included in current models. What drew my attention to ice ages is the manuscript (Climate and Collapse) by agricultural economist Dennis Avery, my coauthor on Unstoppable Global Warming: Every 1500 years [Rowman&Littlefield 2007].  Dennis documents the historic collapse of civilizations, using recorded history and archeological data.  Cold...(Read Full Article)