Deep Ocean Circulation in the North Atlantic and Rapid Climate Change During the Last Ice Age

Jerry McManus of the Lamont-Doherty Earth Observatory discusses how geochemical and isotopic tracers of the deep circulation throughout the last ice age from rapidly accumulating sediments in the North Atlantic Ocean document systematic association of variations in AMOC and abrupt climate change through glaciation and deglaciation. Diminished AMOC accompanied the millennial northern coolings, including the cold, stadial, portions of so-called “Dansgaard-Oeschger (DO) events” as well as the extreme stadial “Heinrich events” associated with catastrophic iceberg discharges. Perhaps most notably, rapid increases in AMOC, in the form of surges in the depth and export of North Atlantic Deep Water from the North Atlantic Basin, accompanied the dramatic northern warmings that punctuated the ice age, underscoring the important potential role of internal Earth systems in climate change.