The current rate of greenhouse gas emissions and resulting rapid melting of Antarctic glaciers is leading a vital deep ocean current towards collapse. The Antarctic overturning circulation current is projected to slow by 40% by 2050, profoundly altering the ocean overturning of heat, fresh water, oxygen, carbon, and nutrients, with impacts felt throughout the global ocean for centuries. It allows nutrients to rise from the ocean’s bottom, supporting about three-quarters of phytoplankton production and forming the global food chain’s basis. The ocean would also be left with a limited ability to absorb CO2 due to stratification of its upper layers. Warm water could increasingly intrude on the western Antarctic ice shelf, creating a feedback loop and even more glacial melting. Deep ocean circulation could weaken twice as fast as the Atlantic Meridional Overturning Circulation. The AMOC carries warm water from the tropics to the North Atlantic Ocean. Its collapse is considered one of the planet’s main potential tipping points.
www.commondreams.org/news/melting-ice-ocean-circulation