Scientists have found that the Antarctic Ocean has been increasing the absorption of carbon dioxide over the last decade. It contradicts past studies that showed that the ocean’s greenhouse gas uptake had stalled since the 1980s. The previous studies raised fears that the Antarctic Ocean had reached a saturation point that could leave more carbon dioxide in the atmosphere.
Antarctic Ocean’s CO2 absorption doubled between 2001 and 2011
However, a new study published in the journal Science shows that the Southern Ocean is pulling greenhouse gases out of the air at a much more efficient rate. It would help limit global warming. The Antarctic Ocean seasonally soaks up vast amounts of CO2 and releases it back like a giant lung later in the year. But the ocean absorbs significantly more carbon dioxide than it releases, removing a large amount of greenhouse gases from the atmosphere.
Nicolas Gruber, the co-author of the study and a professor at ETH Zurich, said the Antarctic Ocean’s absorption of CO2 almost doubled to 1.2 billion tons in 2011 compared to levels a decade earlier. That’s equivalent to the annual man-made carbon emissions from the entire European Union. However, Gruber said it was unclear how long the higher absorption rate would last.
How researchers measured the CO2 concentration
The Antarctic Ocean accounts for over 40% of the global oceanic man-made CO2 absorption. According to Sara Mikaloff-Fletcher of the National Institute of Water and Atmospheric Research in New Zealand, oceans have absorbed about 25% of the man-made greenhouse gas emissions since 1870. It’s unclear how the Antarctic would respond to the future climate changes.
Gruber and his colleagues analyzed measurements of CO2 concentration in the surface waters of the Antarctic Ocean. The study was based on 2.6 million measurements by ships over a period of three decades. Researchers concluded that the ocean’s carbon uptake fluctuates strongly in periodic cycles, rather than increasing in a monotonous way in response to the growing atmospheric CO2 concentration.
There is believed to be a direct relationship between the oceanic carbon absorption and the concentration of CO2 in the atmosphere. The higher the carbon concentration in the air, the more CO2 absorbed by the sea.