It's the middle of winter in Antarctica, and the sea ice surrounding it is at a record low for this time of year.
Beginning around April, sea ice levels in Antarctica have typically entered an annual growth phase and approached their greatest extent for the year around October.
As recently as 2014, this growth phase peaked with a record high extent of sea ice. But since 2016, annual ice extent has declined, falling mostly below the 1981–2010 30-year average. Now NOAA says even though ice cover is still growing for the year, daily extents have been at record lows since April of 2023.
Melting sea ice doesn't contribute to sea level rise on its own, since it's already floating on the ocean surface. But the sea ice surrounds glaciers and other ice shelves on continental Antarctica — and the less sea ice there is, the less protection that inland ice has from warming temperatures.
The water frozen there has the potential to significantly alter global sea levels, were it to melt.
The West Antarctic Ice Sheet, which is on land in Antarctica, this year experienced some of the most significant melting on the continent. If all of its ice melted, it could raise global average sea levels by more than 10 feet.
While such melting is not expected to happen all at once, the effects of ongoing melting are expected to grow more apparent in the coming years.
In 2022, NOAA predicted that in the U.S., sea levels may rise as much as 12 inches on average by 2050. The impacts may also vary regionally — the U.S. East Coast may see up to 14 inches, for example, and the Gulf Coast could experience as much as 18 inches of rise.
Researchers say what melts now will also make it more difficult for Antarctica to regain lost ice later.
Global ocean temperatures are climbing, which melts more ice.
And the less ice there is, the less sunlight is reflected by its bright surface. Instead, darker ocean water absorbs even more of that heat.
If ice maximums continue their downward trend, experts say, later years could see even more ice loss as the effects compound.
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