Ocean Less Effective At Absorbing Carbon Dioxide Emissons

In the Southern Indian Ocean, climate change is leading to stronger winds, which mix waters, bringing CO2 up from the ocean depths to the surface. This is the conclusion of researchers who have studied the latest field measurements carried out by CNRS’s INSU, IPEV and IPSL. As a result, the Southern Ocean can no longer absorb as much atmospheric CO2 as before. Its role as a ‘carbon sink’ has been weakened, and it may now be ten times less efficient than previously estimated. The same trend can be observed at high latitudes in the North Atlantic.
The increase in the amount of CO2 in the atmosphere, which is the cause of climate warming, is the result of human activity (use of fossil fuels and deforestation). However, warming is mitigated by the oceans and by terrestrial ecosystems, which are able to absorb a large part of CO2 emissions. The oceans are the planet’s main carbon sink, but in the last ten years they have become increasingly unable to play this role, in both the northern and southern hemispheres.

This is what has been discovered by Nicolas Metzl and his team at IPSL’s LOCEAN laboratory. Their conclusion is based on data collected by the OISO Indian Ocean observation service, which was set up ten years ago with the backing of INSU, CNRS, IPEV and IPSL in order to better evaluate variations in the oceanic carbon cycle on seasonal to decadal scales. From 1998 to 2008, the OISO observatory carried out repeated campaigns of CO2 measurements in the Southern Indian Ocean between 20 and 60