North Atlantic circulation reduced historical changes in climate

A triangular metal framework holding clear tubes full of ocean sediment is pulled out of the ocean by a winch on a boat. Heat transferring from the surface to the deep ocean in the North Atlantic helped reduce climate swings during the last 1,000 years, according to a newly published paper led by researchers from the Woods Hole Oceanographic Institution (WHOI) and UCL. The paper, published in Science , presents records from North Atlantic sediments that allowed the researchers to investigate temperature changes in the surface and deep ocean throughout the last 1,200 years. From these data the team was able to infer how the ocean has helped transfer heat from the surface to the deep ocean, causing it to reduce the size of past surface climate changes. Co-author Professor David Thornalley (UCL Geography) said: "We only have direct measurements of deep ocean temperature from thermometers for the last 20 to 30 years. These direct measurements suggest that the deep ocean has been absorbing a lot of the heat caused by global warming. A key route for this heat to get from the surface and into the deep ocean is along pathways where water is sinking from the surface to the deep." " We set out to investigate if heat has always been transmitted via one of these pathways in the North Atlantic over the last 1,000 years or so.