Monday 6 December 2021

Southern Ocean’s critical role in battling climate change

A study from NASA has revealed the key role the Southern Ocean has in tackling the impacts of human-induced climate change.

It has found that the ocean absorbs much more carbon from the atmosphere than it releases and is a very strong carbon sink when it comes to halting the effects of greenhouse gas (GHG) emissions on the planet.

The study was conducted due to recent uncertainty in how much atmospheric carbon dioxide (CO2) icy waters truly absorb – from tests on the level of ocean acidity, which increases as the water absorbs the polluting gas.

NASA’s study, however, took a bird’s eye view to understanding the impact of the ocean, using aircraft observations from close to a decade of CO2 levels throughout the Southern Ocean. The results show it to be a far stronger carbon sink than previously thought and a crucial buffer against warming levels.

[caption id="attachment_230989" align="alignnone" width="720"] Image: NASA's Scientific Visualisation Studio[/caption]

The images demonstrated that the ocean absorbs far more CO2 in the southern hemisphere during the summer than it releases during the winter – and far more than the data using ocean acidity levels suggested.

Oceans can absorb the CO2 released from human industry through a process called ‘upwelling’, whereby cold water from the deeper ocean rises to the surface and takes CO2 from the atmosphere back with it as it sinks below once more. This is done with the aid of phytoplankton, which photosynthesise at the top of the water.

The study suggests that more than 40% of human-produced CO2 in the water has been absorbed into the Southern Ocean – highlighting its crucial role in battling global warming.

Lead author of the study, Scientist Matthew Long, commented: “Airborne measurements show a drawdown of carbon dioxide in the lower atmosphere over the Southern Ocean surface in summer, indicating carbon uptake by the ocean.”