Natural climate change: what drives the ice age cycles?

In this presentation, Dr. Michael Palmer discusses the roles of carbon dioxide and of the Milankovitch cycles in the alternating rhythm of ice ages and intermittent warm period. The talk is based on an idea conceived by Ralph Ellis and published jointly by him and Palmer. It illustrates that we are a long way off from a generally accepted, quantitative theory of natural climate change. Without such a baseline, any attempt at quantifying "man-made global warming" will be futile.