Decreasing Sea Ice Increases Ocean Temperatures and Glacier Melt in West Antarctica

Geophysical Research Letters, 21 March 2023

Disappearing sea ice near West Antarctica is sending warm water closer to the continent, with the potential to increase ocean temperatures under discharging glaciers by more than 1°C in the next three decades should today’s high emissions continue. On the other hand, a very low emissions pathway (SSP1-1.9, as described in the IPCC AR6 Synthesis Report), would be able to halt continued sea ice loss around 2060, and thus slow the intrusion of warm water eroding ice shelves. Sea ice serves as a protective barrier. When it declines, strong winds hit the surface of the ocean and could progressively expand the 1000-kilometer-wide Ross Gyre, sending a flood of warm water onto the continental shelf in the Amundsen and Bellingshausen seas. This would increase melt rates far beyond their current range. These vulnerable regions of West Antarctica are already showing signs of a long-term decline in sea ice cover, with record lows observed in February 2023. Some research suggests that the Ross Gyre may have already begun expanding, with 0.3°C of warming observed under West Antarctic ice shelves over the past two decades. Moving immediately to a low emissions pathway is essential to prevent intense shelf warming and maintain the stability of major Antarctic glaciers.

https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2023GL102978