Formation of the North Atlantic Warming Hole by reducing anthropogenic sulphate aerosols

Abstract

The North Atlantic Warming Hole (NAWH) has been observed and predicted due to the increase in carbon dioxide (CO2) concentration. If sulphate aerosols, which have a cooling effect on the atmosphere, are reduced by air pollution control, the NAWH may form as it would if CO2 concentrations increased. In this study, sensitivity experiments using a coupled atmosphere–ocean-aerosol model were conducted by varying the amount of sulphur dioxide (SO2) emissions, a precursor of sulphate which is the primary anthropogenic aerosol in the atmosphere, to analyse the changes in the ocean temperature, salinity, and density. The results showed that although the spatial patterns of the NAWH due to the changes in SO2 emissions was similar to that due to the changes in the CO2 concentrations, the magnitude of the shifts in the ocean parameters due to the changes in SO2 emissions is larger even when changes in global mean temperature are comparable. This can be due to the spatial concentration of sulphate aerosols in the mid-latitudes of the Northern Hemisphere, resulting larger changes in the heat transport from the south on the Gulf Stream and the North Atlantic Current along with changes in freshwater inflow from the Arctic through the Labrador Sea.

Migratory movements of fin whales from the Gulf of St. Lawrence challenge our understanding of the Northwest Atlantic stock structure

“…The comparison with previous studies poses a new challenge: how animals adapt or alter their migration strategies in a changing environment. Parts of the western North Atlantic are among the fastest-warming bodies of water in the world [72][73][74] . The resulting sea ice loss is already associated with an earlier arrival of 30 days (over 27 years) of fin whales in the GSL.…”