Severe 21st-century ocean acidification in Antarctic Marine Protected Areas

Antarctic coastal waters, home to several established or proposed Marine Protected Areas (MPAs), face threats from anthropogenic climate change, particularly ocean acidification (OA). This study projects 21st-century OA in Antarctic MPAs under four emission scenarios using a high-resolution ocean-sea ice-biogeochemistry model. By 2100, pH declines of up to 0.36 (total scale) are projected for the top 200 m, with severe OA throughout the water column in coastal waters due to vigorous vertical mixing of anthropogenic carbon. Aragonite undersaturation becomes ubiquitous under the three highest emission scenarios. The findings underscore the need for strong emission mitigation and further management strategies, including the continuation and expansion of Antarctic MPAs, to reduce pressures on these vulnerable ecosystems.

Cara Nissen, Nicole S. Lovenduski, Cassandra M. Brooks, Mario Hoppema, Ralph Timmermann, Judith Hauck