Atlantic 'cold blob' signals weakening ocean currents, study finds

Scientists have identified a region in the North Atlantic, known as the 'cold blob,' as the only area on Earth that has cooled in recent decades. A new study published in Geophysical Research Letters, led by Prof Dr Stefan Rahmstorf from the Potsdam Institute for Climate Impact Research (PIK), analyzes temperature data and concludes that changing heat transport in the ocean is the primary driver of this phenomenon.

The research indicates that the 'cold blob' is a sign of a weakening Atlantic Meridional Overturning Circulation (AMOC), a crucial system of ocean currents that distributes heat globally. The AMOC carries warm water northwards along the surface and cold water southwards along the seabed. Its weakening is a cause for concern, as further decline could lead to severe impacts on climate and weather conditions in Europe and other regions.

Previous research suggests that melting ice sheets, by reducing the salinity and density of surface seawater, could slow down the AMOC. The authors of the latest study describe 'early warning signals' of the AMOC approaching a tipping point, a shift that could trigger dramatically cold winters in northern Europe and rapid sea level rise along the US east coast. They emphasize that this risk requires urgent attention from policymakers.