Nature Geoscience, 5 May 2022

The accumulation of sea ice near the Antarctic Peninsula provides a buffer that dampens approaching ocean waves, preventing them from smashing into the ice shelves that buttress the glaciers and ice sheet behind. This layer of defence stabilizes the Antarctic Ice Sheet, reducing the number of icebergs breaking off from ice shelves and drifting into the ocean. This study found that local wind patterns as well as rising air and ocean temperatures can decrease the amount of sea ice surrounding the Antarctic Peninsula. When sea ice cover decreases, it exposes the ice shelves to damaging ocean waves. These waves strain the ice to the point of fracturing and, ultimately, dispelling icebergs into the ocean. Abrupt warming and sea ice loss in the Antarctic Peninsula two decades ago led to the catastrophic collapse of the Larsen A and B ice shelves. These events increased the flow of ice into the ocean, accelerating the Antarctic Peninsula’s contribution to sea-level rise. Over the entire satellite record, the release of icebergs from the eastern Antarctic Peninsula almost always occurs during or shortly after some loss of sea ice. This study highlights the often-overlooked importance of sea ice variability to the health of the Antarctic Ice Sheet.