Southern Ocean shows signs of resurgence as world carbon sink

11 Sep 2015

The Southern Ocean surrounding the continent of Antarctica is once again reclaiming its role as a ‘giant lung’ for planet Earth, absorbing huge amounts of CO2, according to new research.

The relatively small ocean had for thousands of years been seen as a carbon sink for the planet, absorbing vast quantities of CO2 from the atmosphere and releasing it back, slightly cleaner, around a year later.

However, the ocean that was absorbing as much as 40pc of the world’s man-made CO2 was just over a decade ago found to have reached a state of saturation where the amount of CO2 absorbed had not increased for more than 20 years.

Now, researchers from ETH Zurich are offering some good news for a change as their models have shown that, since the dawning of the new millennium, the Southern Ocean has actually gained in strength and its ability to absorb CO2.

Measuring the concentration of CO2 in the surface waters of the Southern Ocean south of 35°S, a number of research vessels were able to gather enough data to create a statistical model of the oceanic CO2 concentrations.

Based off these findings, its revival began in 2002 and by 2010 it had reached the optimum level of carbon intake that should be expected on the basis of atmospheric CO2 increases alone.

One of the possible reasons for this turnaround could be the change in wind and temperature as the cooling of surface waters in the Pacific sector enables it to absorb more CO2.

How this will change over the coming decades is still not known to the researchers, however, with one of the researchers, Peter Landschützer, saying: “Our statistical model is not able to predict the future development so it is very critical to continue measuring the surface ocean CO2 concentrations in the Southern Ocean.”

The prevalence of carbon sinks across the planet is increasingly becoming a topic of debate, with news last July that the world’s vast deserts are one of the biggest collective carbon sinks on the planet, absorbing as much as 30pc of the world’s carbon emissions.

Image of Southern Ocean around Antarctica via Shutterstock

Colm Gorey was a senior journalist with Silicon Republic