An AWI study gives a potential explanation as to why the ocean around Antarctica is defying climate model projections and continuing to absorb CO2, despite the effects of climate change.
An AWI study gives a potential explanation as to why the ocean around Antarctica is defying climate model projections and continuing to absorb CO2, despite the effects of climate change.
Climate models suggest that climate change could reduce the Southern Ocean’s ability to absorb carbon dioxide (CO2). However, observational data actually shows that this ability has seen no significant decline in recent decades. In a recent study, researchers from the Alfred Wegener Institute have discovered what may be causing this. Low-salinity water in the upper ocean has typically helped to trap carbon in the deep ocean, which in turn has slowed its release into the atmosphere – until now, that is, because climate change is increasingly altering the Southern Ocean and its function as a carbon sink. The study is published in the journal Nature Climate Change.
Oceans absorb around a quarter of all anthropogenic CO2 emissions released into the atmosphere. Of this total, the Southern Ocean alone stores roughly 40 per cent, making it a key region for containing global warming. The Southern Ocean’s important role comes about due to the ocean circulation in the region, whereby water masses upwell from deeper levels, are renewed and then return to the depths. This process releases natural CO2 from the deep ocean and absorbs and stores anthropogenic CO2 from the atmosphere. How well the Southern Ocean is able to absorb anthropogenic CO2 depends on how much natural CO2 comes to the surface from the deep ocean: the more natural CO2 that rises to the surface from the deeper levels, the less anthropogenic CO2 the Southern Ocean is able to absorb. This process is controlled by ocean circulation and the stratification of different water masses.
Read More: Alfred Wegener Institute
Weddell Sea, Southern Ocean (Photo: Mario Hoppmann)
