Antarctic ice eddies and uneven sea-level rise

New research on the melting of the Antarctic ice sheet shows that this process could raise sea levels by nearly 10 feet by the year 2200, with island nations in the Caribbean and the Pacific feeling the effects most strongly.

A new mechanism of Antarctic ice melt

The research data describe a new, troubling mechanism driving the loss of Antarctic ice: powerful submesoscale eddies beneath ice shelves, acting like underwater storms. According to the study summary, this research links these structures to nearly one-fifth of the seasonal variability in ice melt rates.

The study description emphasizes that the eddies form as a result of the cyclical freezing and melting of ice, which changes the density of the water. It is noted that the discovery of this mechanism helps explain the observed retreat of Antarctica’s grounding line, where the ice detaches from the land and begins to float on the water.

Glacier retreat and sea-level projections

The study summary cites the example of the Hektoria Glacier on the Antarctic Peninsula, which by the end of 2022 had retreated by about 5 miles in just two months. It is noted that this rate was nearly ten times higher than earlier measurements of this glacier’s retreat.

The high-emissions scenario described in the research by Shaina Sadai and Ambarish Karmalkar assumes that by 2100 Antarctica’s contribution alone could raise sea levels by about 1 foot. The same analyses suggest that by 2200 this contribution could reach nearly 10 feet, with sea-level rise in selected regions of the Pacific and Atlantic reaching as much as 14 feet.

Uneven impacts on the Caribbean and the Pacific

The study summary stresses that the gravitational pull of Antarctica’s massive ice sheet currently draws ocean water toward it. As the ice melts and loses mass, this water is expected to shift toward more distant regions, leading to an uneven rise in sea levels.

Island states in the Caribbean, such as Jamaica, and countries in the central Pacific, including the Marshall Islands and Palau, are expected to be particularly vulnerable. The study summary emphasizes that these nations bear disproportionate impacts from the projected sea-level rise, even though their contribution to global greenhouse gas emissions remains minimal.