Moored instruments show decadal drop in AMOC strength


  • Colin Schultz


The Atlantic branch of the global thermohaline circulation, known as the Atlantic meridional overturning circulation (AMOC), carries warm surface waters to the north and cold water southward along the seafloor, redistributing energy throughout the ocean basin. Changes in AMOC behavior have been pegged as an important source of interannual variability for the climates of countries ringing the North Atlantic Ocean. Recent modeling results, along with geologic evidence, have some researchers concerned that the system may ultimately collapse. Though interannual and decadal variabilities in the flow rate of the AMOC are consistent features in numerical simulations, direct observations of the circulation's changing behavior have generally eluded detection.