Friday , September 17 2021

Since the 1970s ice loss from Antarctica has increased sixfold



Antarctic glaciers melt at an accelerated pace over the last four decades as a result of the influx of warm ocean water – an impressive new conclusion that, according to researchers, could mean that the sea level could grow faster than expected in the coming decades.

Antarctica lost 40 billion tons of ice melting to the ocean every year from 1979 to 1989. This figure has grown to 252 billion tonnes a year, starting in 2009, according to a study published on Monday in the National Academy of Sciences. This means that the region loses six times as much ice as it was four decades ago, an unprecedented pace in the era of modern measurement. (For production of one millimeter of world-class sea level about 360 billion tons of ice is needed).

"I do not want to be a suspect," said Eric Ringot, a Earth systems scientist from the University of California at Irvine and NASA. But he said that the weak points that the researchers found in East Antarctica, where the largest ice sheet on the planet lives, deserve a more in-depth study.

"The places where the changes in Antarctica are taking place are not limited to a few places," said Ryno. "They seem broader than we thought. This, in my opinion, is a cause for concern."

The results are the latest sign that the world can face catastrophic consequences if climate change continues. In addition to more frequent droughts, heat waves, severe storms and other extreme weather conditions that could come from a constantly warming Earth, scientists have already predicted that the moors can rise by almost three meters on a global scale by 2100 if the world does not drastically decrease carbon emissions. But in recent years there is growing concern that Antarctica can push it even further.

Such an increase in the sea level could lead to the flooding of island communities around the world, the devastation of wildlife and the threat of drinking water supply. The global sea level has already risen by 7 to 8 inches since 1900.

Antarctica ice contains 57.2 meters of potential sea level rise. This massive body of ice flows into the ocean through a complex array of partially immersed glaciers and thick floating ice spaces, which are called ice shelves. Both the glaciers themselves and the glacier shelves may be as large as large US states or entire countries.

The outer flow of ice is normal and natural, and it is usually compensated for about two trillions of tons of snowfall in Antarctica each year, a process that itself would leave the Earth's level relatively unchanged. However, if the speed of the ice flow is accelerated, the loss of the glacial cover may exceed the amount of snowfall. When this happens, the seas are rising.

This is what the new study says. The researchers came to this conclusion after systematically calculating profits and losses in 65 separate sectors of Antarctica, where large glaciers – or glaciers flowing into the ice shelf – reach the sea.

Western Antarctica – the main leaders of the continent. A study on Monday confirms these findings, detailing how one glacier, Pine Island, has lost more than a trillion tons of ice since 1979. Glacier Tweets, the largest and potentially most vulnerable in the region, has lost another 634 billion. The entire Antarctic West Ancient Ice Shield is capable of raising the sea level by 5.28 meters, or 17.32 feet, and now loses 159 billion tons annually.

The most striking result of the study on Monday is the statement that East Antarctica, which contains the largest amount of ice on the continent – a huge leaf that can increase the potential sea level by almost 170 feet – also experiences serious melting.

A new study shows how some of the massive glaciers that have been studied so far are relatively small, actually losing a significant amount of ice. This includes Cook and Ninnis, which are the gateway to the massive Wilkes Ice Cream Basin and other glaciers known as Dibble, Frost, Holmes and Denman.

Denman, for example, has almost 5 feet of potential sea level rise and lost nearly 200 billion tons of ice. And she remains anxiously vulnerable. The study notes that the glacier is "grounded on a ridge with a steep retrograde slope directly above the current", which means that additional losses can lead to a quick retreat of the glacier.

"It is known that Western Antarctica and the Antarctic Peninsula are losing mass, but finding that massive mass losses are also occurring in East Antarctica is very important as there is such a large equivalent of sea level in these basins. , – said Christine Dow, a glacier expert at Waterloo University in Canada. "It shows that we can not ignore the Eastern Antarctic and need to focus on those areas that are rapidly losing weight, especially those with backward slopes that can lead to a rapid breakdown of ice and rising sea levels."

The new study is in some way consistent with the large study published last year by a group of 80 scientists who found that the loss of Antarctic ice has tripled over decades and now stands at 219 billion tonnes annually. This study did not find such large losses from East Antarctica, although it was noted that there is a great deal of uncertainty as to what is happening there.

"We still need to work to align these new estimates," said Beata Xato, an Antarctic expert at the University of Buffalo, who was the author of the previous study.

The bottom line is that Antarctica loses a lot of ice and that there are vulnerable areas throughout the East and West of Antarctica, but with slight signs of slowing down, since the oceans are only warmer. In particular, according to Rino, key parts of East Antarctica, which was the subject of less attention from researchers in the past, require a much closer look and quick.

"Traditional thought from many decades because nothing is happening in Eastern Antarctica," said Rinuo, adding: "It's a bit like the one you want for the real thing."


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