Antarctic Sea Ice Records Third-Smallest Winter Extent

Antarctic sea ice has reached its third-lowest winter maximum on record since satellite observations began 47 years ago, according to data from the U.S. National Snow and Ice Data Center (NSIDC).

Satellite measurements show that sea ice around the continent peaked this winter at 17.81 million square kilometers (6.88 million square miles). This figure is 900,000 square kilometers below the 1981–2010 average, marking the third-smallest winter peak after the record lows of 2023 and 2024.

Experts warn that the persistent decline in Antarctic Sea ice raises concerns about the stability of the Antarctic Ice Sheet. Reduced sea ice can accelerate glacial melting, which in turn contributes to global sea level rise.

During the Southern Hemisphere’s winter, Antarctic sea ice typically expands up to 2,000 kilometers (1,200 miles) from the continent, reaching an average maximum of 18.71 million square kilometers (7.22 million square miles)—roughly twice the size of Canada.

Polar Contrasts: Arctic vs. Antarctic

While the Arctic has shown a clear, decades-long downward trend in sea ice due to rapid warming—known as polar amplification—Antarctica has displayed greater variability, making trends harder to pin down.

• Arctic Sea Ice: Constrained by surrounding landmasses and influenced by the Atlantic and Pacific, the Arctic Ocean’s thick multiyear ice has steadily thinned since the 1990s. Sea ice there continues to retreat in step with rising global temperatures.

• Antarctic Sea Ice: Surrounded by the open Southern Ocean, Antarctic sea ice expansion has historically fluctuated, but recent consecutive years of record lows suggest a possible shift toward long-term decline.

Why Antarctic Sea Ice Matters

Antarctic sea ice not only reflects solar radiation, helping cool the planet, but also plays a vital role in buttressing the Antarctic Ice Sheet. Without this stabilizing effect, massive glaciers could flow more rapidly into the ocean, significantly amplifying sea level rise.

In 2023, Antarctic sea ice reached an unprecedented winter low, with extent dropping 1.75 million square kilometers (676,000 square miles) below the long-term average. This year’s measurements, though slightly higher, remain a troubling continuation of that downward trajectory.

Regions particularly affected include the Indian Ocean sector and the Bellingshausen Sea, where sea ice coverage remains well below average.

The writer of this article is Dr. Seema Javed, an environmentalist & a communications professional in the field of climate and energy