Two Antarctic glaciers are breaking and this may have major consequences for the rise in sea level


Pine Island and the Thwaites Glacier, which sits along the Amundsen Sea shoreline in West Antarctica, are among the fastest-changing glaciers in the region, already accounting for 5% of global sea level. Scientists say that glaciers are highly sensitive to climate change.
A new study published Monday in the Proceedings of the National Academy of Sciences found that glaciers are weakening their foundations and that damage over the past few decades has been accelerating their retreat and possible future collapse of their ice shelves is.

The researchers used satellite data to document the growth of damaged areas from 1997 to 2019, led by satellite expert Steph Lermet of Delft University of Technology in the Netherlands. The images showed open fractures in highly drained areas and glaciers.

While the rapid ice loss and melt of these Antarctic glaciers have been well documented, new studies suggest that future ice shelves may have a future disintegration.

“We knew they were sleeping giants and were losing a lot of miles (of ice), but still there is still a huge uncertainty,” Lermitet said. “These are in the early stage of disintegration of ice shelves, they are starting to separate.”

The Thwaites Glacier is one of the largest and most volatile ice streams in Antarctica. It is a massive mass of over 192,000 square kilometers (74,000 square miles) – an area the size of the US state of Florida or Great Britain.

The two glaciers effectively act as arteries that connect the West Antarctic ice sheet to the ocean. At their base are permanent floating ice shelves that act like a fast flowing ice behind it. The region holds enough ice to raise global sea levels by 1.2 m (4 ft) according to NASA.

So what is happening to the glaciers now?

Human-induced warming of our oceans and atmosphere because the increasing release of heat-trapping greenhouse gases is weakening the planet’s ice shelves.

Warming of this ocean has increased the melting and cooling (ice crumbling) of Pine Island and Thwaites glaciers, studies show, while declining icebergs mean glaciers cannot replenish themselves.

The damage researchers found pointed to a weakening of the shear margin of the glaciers – in areas of floating ice ridges where fast moving ice meets under slow moving ice or rock.

“Usually the ice shelf acts like slow traffic. It is floating on the ocean, but there is ice traffic behind it.” “So if you weaken this slow car, the snow discharges more quickly.”

This is exactly what the researchers saw – and they believe that there will be massive ice loss in these severely weakened parts of the glacier. The study makes the case that this process should be included in models that increase sea level, which is not currently part of it.

Researchers found that tearing of the shear margin of the Pine Island Glacier has been documented since 1999, with their satellite imagery showing a dramatic loss in 2016.

Likewise, damage to the Thwaites glacier began to increase further upstream in 2016 and fractures rapidly opened near the grounding line of the glacier, which meets the ice reef.

Researchers have warned that this process is creating a feedback loop – where a weak ice shelf is damaging the weak Qatar margin of the glacier, causing more damage and disintegration of the ice shelf.

Isabella Velikogna, a professor of earth systems science at the University of California Irvine who was not involved in the study, stated that, “With the process of weakening the ice shelf included in the model, it is likely that the glacier will move. ” Will occur soon and be larger in magnitude, meaning that sea levels will rise faster than currently anticipated. ”

Velikogna said there are other processes that play a “very large role” in glacier development, such as “the rate of retreat of a grounding line forced by a warm ocean.”

Glacier in trouble

The study comes on the heels of research published last week found channels deep beneath the Thights Glacier, which may allow warm ocean water to melt under its ice.

The cavities hidden under the ice shelf are likely to pass through the passage, through which the warm sea water passes from the bottom of the ice to the grounding line, he said.

Over the past three decades, the rate of snow loss from Thwaites and its neighboring glaciers has increased more than five times. If the Thwaites were to fall, it would have increased the sea level by about 25 inches (64 cm).

According to the new study, Greenland's ice sheet has melted without any return
And there is more bad news for glaciers on the other side of the world. On Monday, scientists announced that a nearly 44-square-mile portion, twice the size of Manhattan, had broken through the Arctic’s largest remaining ice shelf in northeast Greenland in the past two years, causing its rapid Fear of erosion has increased.

The region’s ice sheet is the second largest in the world behind Antarctica, and its annual melt contributes more than a millimeter rise in sea level every year.

These recent findings from Antarctica suggest that the glaciers are “weakening from all angles,” Lermitet said.

“Most of the weakening in this part of Antarctica is coming from below,” he said. “Warm ocean waters reach the base of (glaciers) and weaken them. What we have seen is that it becomes so weak, that they accelerate and once they speed up, The shear margin intensifies and breaks down. ”

Velikogna said the research pointed to “another Akilis heel of the system that is conducive to rapid retreat, and has started with climate change.”

“It seems that the more we look at these systems, the more they evolve, the more we think about them disappear more quickly,” she said. “We must act quickly to control climate change to preserve our future. Now is the time to act.”

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