Antarctic sea ice shrank last week to its smallest extent in 45 years of satellite record, US researchers said Monday.
The National Snow and Ice Data Center (NSIDC) at the University of Colorado at Boulder noted that Antarctic sea ice shrank to 1.79 million square kilometers on February 21.
This figure exceeded the previous record low in 2022 by 136,000 square kilometers.
The NSIDC scientists stressed that the latest figure is preliminary as more melting is still possible later in the season, while saying they will release a final figure on ice extent in early March.
Melting sea ice exposes the thick ice shelves that support the Antarctic ice sheet to waves and warmer temperatures, although it has no discernible impact on sea level because the ice is already in the ocean.
However, the ice cap, a thick freshwater glacier that covers Antarctica, is the subject of special attention from scientists because it contains enough water to cause, if it melts, a catastrophic rise in the level of the oceans.
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“Antarctica’s response to climate change has been different from that of the Arctic,” said Ted Scambos, a research scientist at the Cooperative Institute for Research in Environmental Sciences (CIRES).
“The downward trend in sea ice may be a sign that global warming is finally affecting the floating ice surrounding Antarctica, but it will take several more years to be sure,” he added.
The Antarctic cycle undergoes major annual variations during its thawing summers and freezing winters, and the continent has not experienced the rapid melting of the last four decades that ravages the Greenland and Arctic ice caps due to global warming.
But the high rate of melting since 2016 raises concerns that a significant downward trend is taking hold.
Sea ice is problematic because it contributes to accelerating global warming.
When white sea ice – which returns up to 90% of solar energy to space – is replaced by a dark, thawed sea, the water instead absorbs a similar percentage of the Sun’s heat.
Globally, last year was the fifth or sixth warmest on record, despite cooling caused by a natural La Niña weather pattern.