Delayed Antarctic sea-ice decline in high-resolution climate change simulations

• Published in: Nature Communications
• Main Authors: Rackow, Thomas, Danilov, Sergey, Goessling, Helge, Hellmer, Hartmut, Sein, Dmitry, Semmler, Tido, Sidorenko, Dmitry, Jung, Thomas
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Springer 2022
• Subjects: Antarctic; Arctic; Southern Ocean; The Antarctic; Antarc*; Antarctica; Climate change; Global warming; Sea ice
• Online Access: https://epic.awi.de/id/eprint/55749/; https://epic.awi.de/id/eprint/55749/1/rackow_2022_s41467-022-28259-y.pdf; https://doi.org/10.1038/s41467-022-28259-y; https://hdl.handle.net/10013/epic.d28baca2-422a-40ef-b91b-d861ca627c43

Despite global warming and Arctic sea-ice loss, on average the Antarctic sea-ice extent has not declined since 1979 when satellite data became available. In contrast, climate model simulations tend to exhibit strong negative sea-ice trends for the same period. This Antarctic sea-ice paradox leads to low confidence in 21st-century sea-ice projections. Here we present multi-resolution climate change projections that account for Southern Ocean mesoscale eddies. The high-resolution configuration simulates stable September Antarctic sea-ice extent that is not projected to decline until the mid-21st century. We argue that one reason for this finding is a more realistic ocean circulation that increases the equatorward heat transport response to global warming. As a result, the ocean becomes more efficient at moderating the anthropogenic warming around Antarctica and hence at delaying sea-ice decline. Our study suggests that explicitly simulating Southern Ocean eddies is necessary for providing Antarctic sea-ice projections with higher confidence.