Two Antarctic glaciers are collapsing and rising sea levels could have major consequences

The Pine Island and Thaiwates Glaciers, which sit side by side on the Amundsen Sea in West Antarctica, are one of the region’s fastest-changing glaciers, already accounting for 5% of global sea level rise. There are glaciers called scientists Very sensitive Towards seasonal change.

A new study, Published The National Academy of Sciences on Monday found that glaciers are weakening their foundations and that the damage over the past few decades is accelerating their return and the possibility of collapse of their ice shelves in the future. Is.

Researchers led by Steve Lermit, a satellite expert at Delft University of Technology in the Netherlands, used satellite data to document the growth of damaged areas from 1997 to 2019. The images show areas with high defects and open fractures in the glaciers.

While Rapid snow loss And these Antarctic glaciers have melted Is well documented, A new study suggests that upcoming snow selfies may be worse in the future.

“We knew they were sleeping giants and these were people who were losing a lot of miles (of ice), but how far and how much still remains a great uncertainty,” Lermit said. “These ice shelves are in the process of breaking down, they’re starting to crack.”

The Thaiweat Glacier is one of the largest and most unstable ice streams in Antarctica. It is a vast cluster of over 192,000 square kilometers (74,000 square miles) – the size of Florida in the United States, or the size of Great Britain.

Both glaciers act as arteries Connecting West Antarctic ice sheet ocean. At their base are permanent floating ice shelves that act as fast-moving ice buttons behind it. In this area, according to NASA, there is enough ice to raise the sea level by 1.2 meters (4 feet) globally.

So what is happening to glaciers now?

The increasing release of heat-trapping greenhouse gases from human oceans and the human environment is weakening the planet’s ice sheets.

The warming of this ocean has increased the melting and bedding of the Pine Island and Thawites Glaciers, studies show. The fall of snow That means glaciers can’t fill themselves.

Damaged researchers point to the weakening of the shear margin of glaciers – on the edge of floating ice where high-speed ice is found under slow-moving ice or rock.

“Normally the ice shelf acts like slow traffic. It floats on the ocean but it suppresses the ice traffic behind it,” Lermit said. “So if you weaken this slow car, the ice discharges faster.”

Researchers have seen exactly this – and they believe that these very fragile parts of the glacier will increase the loss of mass ice. The study makes it a case that this process should be included in models that show sea level rise, which is not currently part of it.

The researchers found that cracks in the shear margins of the Pine Island Glacier have been documented since 1999 1999 1999. Their satellite imagery shows that the damage dra 2016matically. Has grown dramatically.

Similarly, damage to the Thaiweats Glacier began to increase further in 2016, and fractures began to open rapidly near the glacier’s grounding line, where the iceberg meets the bed.

The researchers warn that the process is creating a reaction loop – where the weakening of the ice is accelerating the damage to the glacier’s weak shear margins, resulting in further damage and breakage of the ice shelf.

Isabella Velegogna, a professor of earth systems science at the University of California, Irvine, who was not involved in the study, said: Will be larger in magnitude, which means that sea levels will rise faster than current estimates. “

There are other processes that play a “huge role” in the evolution of glaciers, such as “the rate of retreat of the grounding line forced by a warm ocean,” Velegogana said.

Glacier in trouble

The study comes at the top The research was published last week Who have deep channels beneath the Thaiweats Glacier can allow warm ocean water Melt down Its wet.

He said that the ditches hidden under the ice are likely to be the route through which the hot sea water goes to the ground ing under the ice sheet.

Over the past three decades, the rate of ice loss from Thwaites and neighboring glaciers has more than increased fivefold. If the collapse of the thymus were known, it could cause an increase in sea level of about 25 inches (64 centimeters).

Greenland's ice sheet has melted at some point of return, according to a new study

And there’s more bad news for glaciers on the other side of the world. on Monday, Scientists announced That 44-kilometer-mile section, nearly twice the size of Manhattan, has broken the Arctic’s largest remaining ice shelf in northeastern Greenland in the past two years, raising fears of its rapid dissolution.

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

Recent findings from Antarctica show that glaciers are “weakening from all angles,” Lermit said.

“The weakest part of this part of Antarctica is coming from below,” he said. “Hot water goes to the base of ocean water (glaciers) and weakens them. What we’ve seen is that it gets so weak, that they get faster and once they get faster. , Then the shear margins become faster and begin to break. “

Valegogna said the discovery “points to the heel of another Achilles system that is suitable for an early return duc, and began with climate change.”

“It seems that the more we look at the evolution of these systems, the more we look at the reasons why they disappear faster than we think,” he said. “We need to act quickly on tackling climate change to secure our future. Now is the time to act.”