Abstract

The cause of the Little Ice Age was the reduction of northward flow of warmer Gulf Stream water west of Europe. This flow contributes to the Northern Gyre, which warms first Iceland and then Greenland. The flow reduction was caused by a 1500-year cyclic increase of lower salinity Antarctic bottom water that upwells and enters the high latitude North Atlantic and tends to reduce intermediate level deep water formation. This feedback increase of bottom water flow is produced cyclically by enhanced freezing over the Antarctic continental shelf. This occurs with a delayed increase of somewhat warmer and more saline intermediate level water from the North arrives in the Southern Ocean and minimizes the sea ice over the continental shelf and its insulating effect from the cold atmosphere.