Only Low Emissions Can Protect Even Best-case Antarctic MPAs from Severe Ocean Acidification

Nature Communications, 4 January 2024

Only the lowest emissions scenarios (SSP1-2.6) with rapid and aggressive fossil fuel reductions can prevent “severe” acidification in the Southern Ocean, while even intermediate scenarios (SSP 2-4.5 and above) will expose ecosystems along the Antarctic continental shelves to increasingly hazardous conditions from surface to seafloor. Plankton at the base of the food web will grow at a slower rate or die out when the water becomes too acidic, with harm extending to shelled creatures and disrupting higher trophic levels all the way to top predators, such as whales and penguins. Authors highlighted the need to establish more Marine Protected Areas (MPAs); especially in the Weddell Sea, which could serve as a sanctuary from acidification due to its higher sea ice coverage shielding that region from the most rapid warming and acidification. However, even the Weddell Sea’s protective status ultimately will disappear with anything but the lowest emissions pathways, with only a slight delay in severe acidification under intermediate or high emissions.

https://www.nature.com/articles/s41467-023-44438-x