Meltwater Intensifies Southern Ocean Freshening Around Antarctica

Scientific Reports, 10 January 2022

Rising global temperatures have shifted westerly winds closer to the Antarctic continent, sending warm eddies of water into cavities at the base of Antarctica’s ice sheets, and accelerating the flow of meltwater into the ocean. During the past 20 years, the flow of Antarctic meltwater into the Southern Ocean has increased to a new maximum of 268 gigatons per year. Since 1960, this meltwater has contributed 63%, 28%, and 92% of the total freshening in the Atlantic, Indian, and Pacific regions of Antarctica’s coastal waters, respectively. This freshening of the Southern Ocean prevents certain stratification (ocean water layers) patterns from fully forming. Much like the more well-known freshening and warming in the North Atlantic with Greenland ice sheet loss, this Southern Ocean freshening may eventually weaken the AMOC, one of the largest overturning circulation systems in the world. The dramatic ice loss occurring along the edges of Antarctica, and intensified freshening may also have negative impacts on Southern Ocean ecosystems and species; and underscores the influence this ice sheet holds over the global climate system.