In easy historical steps, this book describes the efforts of scientists to understand why ice ages have occurred and the evidence for the role that the Mediterranean Sea plays in the grand sequence of climate changes over the last three million years. You will see how the orbital theory of ice ages advocated by Croll and Milankovitch passed through cycles of scientific acceptance and rejection leading to the modified version put forth in this book. This model of climate change is much more consistent with the geological records than earlier versions. The model predicts a major atmospheric circulation change in northeastern Canada, causing the onset of a new ice age in the next few decades when deepwater formation begins in Baffin Bay. This change is predicted due to the progressive loss of the Arctic Ocean pack ice cover (forty percent thinner now than thirty years ago) caused by global warming and the increasing saline outflow from the Mediterranean at Gibraltar.