Discussion: In a recent article in the newspaper Aftenbladet, petroleum geologist and professor emeritus Per Arne Bjorkum misled the public by falsely claiming that Antarctica’s total ice mass had not changed since the 1980s.
The curious Edar Billström
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He adds that as global temperatures become increasingly warm, Antarctica may not have a net loss of ice due to “self-regulation.” Therefore, it will not contribute to increasing sea levels. Historical climate data, ongoing measurements of ice, land and sea temperatures, satellite observations of mass balances and research on tipping points in the climate system tell us something very different.
It is extremely important that the public and decision-makers are properly informed about how human-caused global warming will affect the climate and environmental development in Antarctica. Increased melting on the planet’s southernmost continent, which contains 90% of the world’s ice and 70% of all fresh water, could accelerate the continuing rise in sea level at a rate of 4 millimeters per year on a global average. The scale of catastrophic flooding is increasing in some of the world’s most densely populated coastal areas and low-lying island communities. According to the sixth major report of the UN Climate Commission As of 2021, Antarctica has lost 2,670 gigatons (billion tons) of ice between 1992 and 2020, mainly due to the melting of coastal glaciers in West Antarctica.
Major melting and catastrophic sea level rise may take centuries, but they could also accelerate much earlier.
This is equivalent to 40 percent of the water volume in the Skagerrak, or a 7.5 mm increase in global sea level. In the 20-year period 2002-2023, annual ice loss averaged 146 gigatons, equivalent to roughly half the mass loss from the Greenland ice sheet. This number reflects a historical deviation in 2022. Icefall figures after 1992 are based mainly on satellite measurements from NASA And Issa.
Skips the important part
In a study published in the scientific journal Proceedings of the National Academy of Sciences (PNAS) in 2019, American and Dutch glaciologists estimated that Antarctica also experienced a limited net loss of mass in the decade 1979-1990 — before satellite measurements began. Bjorkum notes that the 2022 edition of the American Meteorological Society (AMS) Annual Climate Reports indicates a net increase in Antarctic ice mass. This was due to abnormal weather conditions with large amounts of snow falling in parts of the continent. The increase is estimated at about 290 billion gigatons. As a volume of water, this is equivalent to 0.8 mm of global sea level. Meanwhile, according to the AMS report, “something like this is unlikely to continue.” “We expect a return to net mass loss from the Antarctic ice sheet in the coming years,” the authors of the Antarctic chapter wrote. Bjørkum goes beyond this.
It is ironic that Bjorkum accuses Aftenbladet of scaring readers with a recent article on the blanket ice ban about the danger of ice collapse in West Antarctica, which is vulnerable to melting. A number of other media outlets also used this issue. As part of his theoretical scientific campaign against climate research, he concludes The latest study is in the journal Nature Climate Change On which the NTB case is based, via The Guardian and Associated Press (AP), for data cherry-picking and professional fraud. The threat of sea level rise from the White Continent is almost excluded. He bases this on a one-year deviation from the ongoing melting trend, mixing up the surface mass balance and the overall mass balance, giving an incorrect conclusion about the last 40 years of Antarctica’s ice history – as well as trivial home-made theories. About further development, it is based on one pilot study in the professional journal The Cryosphere.
A major melt threatens
The scientists behind it Current study in nature climate change Self-reinforcing melting of the West Antarctica ice shelf is believed to be inevitable for the rest of this century, even if it succeeds, against all odds, in reducing emissions in line with the Paris Agreement target of 1.5 degrees. The conclusion from one study should be treated with caution. But this is no more extreme than the fact that it joins growing scientific concern that large parts of the Amundsen region, the vulnerable “underbelly” of West Antarctica, may already have passed the tipping point. Major melting and catastrophic sea level rise may take centuries, but they could also accelerate much earlier.
Since the end of the 1990s, one of the largest ice basins in West Antarctica, the huge Thwaites Glacier, or the so-called Doomsday Glacier, has been operating, which empties into the Amundsen Sea and is the size of Great Britain, with an ice volume equivalent to 60 centimeters of ice level. The surface of the sea, Withdrew 14 kilometers back. Like most glacial complexes in West Antarctica, the Thwaites River lies on a landscape incised well below sea level. The additional retreat opens the way for relatively warm seawater to flow into the deep canyons and channels in these underwater landscapes and effectively feed the underside of the glacier. There’s a process that scientists recently documented, and it’s happening beneath the ice shelf floating in front of us.