Warm Meltwater from Neighboring Glaciers Further Destabilizes Thwaites Ice Shelf

Nature Communications, 21 December 2022

Small ocean currents known as “gyres” can trap heat along the edges of West Antarctica, sending warm meltwater from one ice shelf into cavities along the base of other downstream shelves, especially during the summer months. This intrusion of freshwater triggers additional melting, making these downstream ice shelves more vulnerable to collapse. During the winter, weakened gyres pose an additional threat. When ocean currents shift and sea ice accumulates, it dampens the flow of wind over the ocean and weakens gyres. When winter gyres lack the strength to transport summer meltwater away from Antarctica, this allows warm water to pool near the base of ice shelves. Three years ago, ocean temperatures increased underneath the Thwaites Ice Shelf due to an unusually strong influx of warm meltwater from the nearby Pine Island Glacier. The gyre from Pine Island directed these warmer waters into the shallow cavities beneath Thwaites, weakening its ability to restrain the glacier behind it. Thwaites is one of the fastest flowing glaciers in West Antarctica, and the largest current contributor to global sea level rise from Antarctica. These findings reveal the importance of local ocean circulation and sea ice on Antarctic ice sheet stability and future sea-level rise projections.

https://www.nature.com/articles/s41467-022-35499-5