Global Courant
Concerns that the world is experiencing the beginning of a long-term trend of Antarctic sea ice decline.
The sea ice covering the ocean around Antarctica reached a record low in winter, a preliminary analysis of US satellite data shows, and scientists fear the impact of climate change on the South Pole is increasing.
As the Southern Hemisphere transitions into spring, Antarctic sea ice had only reached a maximum extent of 16.96 million square kilometers (6.55 million square miles) as of September 10, according to the US space agency NASA and the National Snow and Ice Data Center (NSIDC). said Monday.
“This is by a wide margin the lowest sea ice maximum in the sea ice record from 1979 to 2023,” according to the NSIDC, a government-backed program at the University of Colorado Boulder.
At one point this year, sea ice had fallen to 1.03 million square kilometers (more than 397,000 square miles), smaller than the previous record low and an area about the size of Texas and California combined.
“It’s a record-breaking sea ice cover in Antarctica,” NSIDC scientist Walt Meier said in commentary published by NASA.
On September 10, Antarctic sea ice likely reached its annual maximum extent of 16.96 million square kilometers (6.55 million square miles). This is by a wide margin the lowest sea ice maximum in the sea ice record from 1979 to 2023. pic.twitter.com/XQ7LwWAzaG
— National Snow and Ice Data Center (@NSIDC) September 25, 2023
By February, at the height of the austral summer, the Antarctic sea ice pack had reached a minimum extent of 1.79 million square kilometers (over 691,000 square miles), also a record, according to the NSIDC.
The ice pack then grew back at an unusually slow pace, despite the onset of winter.
Meier said sea ice growth “appeared low around almost the entire continent, unlike any region.”
Although the Arctic has been hit hard by climate change over the past decade, with sea ice deteriorating rapidly as the northern region warms four times faster than the global average, it is less certain how warming temperatures will affect sea ice near the South Pole.
Sea ice update 2023
Arctic sea ice reached its annual minimum on September 19, making it the sixth lowest year in the satellite record. @NASA & @NSIDC report. Antarctic sea ice reached its lowest maximum on record on September 10, when the ice should be growing rapidly. pic.twitter.com/FO5931UA49
— NASA Earth (@NASAEarth) September 25, 2023
For decades, the Antarctic sea ice pack had remained stable, even growing slightly between 2007 and 2016.
But “since August 2016, the trend in Antarctic sea ice extent has been in sharp decline for almost all months,” the NSIDC said.
The shift in recent years to record low conditions around the South Pole has scientists concerned that climate change could finally be affecting the Antarctic sea ice.
There is debate among scientists about the exact cause of this shift, and some hesitate to make a formal connection with global warming. Climate models have historically struggled to predict changes in the Antarctic ice pack.
The downward trend is now thought to be related to warming of the upper ocean layer, the NSIDC said.
“There is some concern that this could be the start of a long-term trend of Antarctic sea ice decline as global oceans warm,” the report said.
The NSIDC warned Monday that the findings are preliminary because “changing winds or late-season growth could still increase the extent of Antarctic ice.” A full analysis of the data will be released in early October.
On the other side of the world, where summer is coming to an end, Arctic sea ice reached a low of 4.23 million square kilometers (1.6 million square miles), the NSIDC said. It represents the sixth lowest minimum in 45 years of record-keeping.
Meier also said there was remarkably little ice in the Northwest Passage, the sea route through the Arctic Ocean that connects the Atlantic and Pacific Oceans.
“It’s more open there than before,” says Meier.
“There also appears to be a lot more loose ice at a lower concentration – even towards the North Pole – and areas that were quite compact, solid ice shelves in the summer. This has been happening more and more in recent years,” he says.
