Tuesday, June 18, 2013

The Antarctic Half of the Global Thermohaline Circulation Is Faltering


The sudden cooling of Europe, triggered by collapse of the global thermohaline circulation in the north Atlantic and the slowing of the Gulf Stream has been popularized by the movies and the media. The southern half of the global thermohaline circulation is as important to global climate but has not been popularized. The global oceans' coldest water, Antarctic bottom water forms in several key spots around Antarctica. The water is so cold and dense that it spreads out along the bottom all of the major ocean basins except the north Atlantic and Arctic. Multiple recent reports provide strong evidence that the formation of Antarctic bottom water has slowed dramatically in response to massive subsurface melting of ice shelves and glaciers. The meltwater is freshening a layer of water found between depths of 50 and 150 meters. This lightened layer is impeding the formation of Antarctic bottom water, causing the Antarctic half of the global thermohaline circulation to falter. Read More