The Southern Ocean is absorbing more CO2 than expected due to ice melt, but long-term stability is uncertain.

The Southern Ocean continues to absorb large amounts of atmospheric carbon dioxide, defying earlier climate model predictions, due to increased freshwater from melting ice and precipitation. This freshening strengthens ocean stratification, preventing carbon-rich deep water from rising and trapping CO2 in deeper layers. While this process has sustained the region’s carbon sink capacity—responsible for about 40% of oceanic carbon uptake—the long-term stability remains uncertain as climate change progresses.