Antarctic Ocean Weakness: Changing Role of Global Carbon Sink

Two of nature’s main allies in combating global warming—terrestrial forests and the ocean—are losing their carbon sink capacity. The most worrying of these is the weakening of the Southern Ocean around Antarctica.

The ocean used to help stabilize the climate by absorbing roughly one-third of human-made carbon emissions. But now scientists are warning that its carbon sink capacity is unexpectedly declining, a major setback for climate models.

A study by NOAA and the Scripps Institution of Oceanography shows that carbon dioxide levels in the Southern Ocean have risen over the past decade.

Westerly winds have strengthened due to climate change, causing warm, carbon-rich water from the deep ocean to rise to the surface. This water is releasing carbon into the atmosphere, which is reversing the ocean’s carbon absorption role.

Scientists see this as a significant ‘tipping point’. As the ocean warms, it absorbs less CO₂ from the atmosphere. If the world’s largest carbon sink deteriorates, atmospheric carbon will rise quickly, leading to a rapid increase in global temperatures beyond the 1.5°C limit of the Paris Agreement.

International policymakers need to take quicker and stronger actions to cut fossil fuel emissions.