Southern Ocean’s ability to absorb carbon can fluctuate over time

Nature : The ability of Earth’s oceans to act as a carbon sink for anthropogenic carbon dioxide changes more drastically than researchers had previously thought. The CO₂ uptake of the Southern Ocean, which accounts for about 40% of total ocean uptake, slowed dramatically in the 1980s and 1990s, which worried scientists who were concerned about climate change. However, since the early 2000s, the Southern Ocean’s CO₂ uptake has been increasing. According to a recent study published in Science, that fluctuation may be due to changing wind patterns. During the earlier decades, winds over the Southern Ocean were pushing surface water north, which appears to have caused an upwelling of deep ocean water already saturated with CO₂. Since 2002 the winds shifted and more CO₂ was once again being absorbed, and by 2012, according to the study, “the Southern Ocean had regained its expected strength.”