The so-called terminal glaciers in Antarctica are losing ice at the fastest rate in 5,500 years, raising concerns about the future of ice sheets and the potential for catastrophic sea-level rise caused by the melting ice of frozen continents.
This finding comes from a study of prehistoric marine sediments found on the coast around the “Worst Day” Glacier Glacier and the adjacent Pine Island Glacier on the West Antarctic Ice Sheet. Freezing news? Antarctica glacier melting, Climate changeGoing faster than ever in recorded history, researchers reported June 9 in the journal Nature Geoscience (Opens in a new tab)..
“The melting rates of these currently rising ice can have a devastating effect on the future Earth’s surface in a warming world, with these important arteries rupturing from the center of the West Antarctic Ice Sheet. It may indicate that it accelerates the influx into the sexual ocean. “-Author Dylan Ludo, Earth Scientist at Imperial College London, Said in a statement..
“Is it too late to stop the bleeding?” Ruud asked.
As one of Antarctica Thwaite, the most meltable glacier, has earned a nickname. “Glacier at the end..“Since the 1980s, Sweat has lost an estimated 595 billion tonnes (540 billion metric tonnes) of ice, contributing a 4% rise in world sea level. Sweat and its northern neighbor, the Pine Island Glacier, are vast. The surface area is about 74,130 square miles (192,000 square kilometers) (about the same size as the UK), and Pine Island is 62,660 square miles (162,300 square kilometers).
The sea-facing edges of the glaciers are located above a bowl-like basin, exposing the underside of both glaciers to a stream of warm, dense, salty water. This warm water not only melts the glaciers that stretch into the Amundsen Sea, but also blows them away from below and unlocks them from major anchorage points in the north. In addition, this melting from below weakens the glacier, making it more susceptible to surface destruction that can spread throughout the ice sheet and can crush the ice sheet. If the entire West Antarctic Ice Sheet collapses and melts into the sea, the world’s sea level will rise by about 11 feet (3.4 meters).
To compare the melting rates of today’s glaciers with those of glaciers in the distant past, scientists sought clues on the beaches of the Antarctic near where the glaciers ended in the ocean. Towards the end of the Last Glacial Period (about 11,500 years ago), some of the frozen weights melted and flowed into the sea as the ice squeezed the land, causing the land to bounce off and revealing the previously hidden coastline under the waves. I did. Scientists wanted to discover how quickly the ice disappeared from the land before moving forward again by measuring the age and height of about 20 coastlines.
Researchers estimated the age of the coastline by collecting small fragments of ancient shells and penguin bones before analyzing ancient biological material. Radiocarbon dating.. This method identifies the age of organic matter by measuring the amount of carbon-14, which is a radioactive substance. carbon Isotopes, or variants with different numbers of neutrons, Earth It is easily absorbed by plants and animals. When an animal dies, it stops accumulating carbon-14 in the tissue and begins to absorb less. The half-life of carbon-14 (or the time it takes for half of it to decay) is 5,730 years, and scientists died thousands of years ago by measuring the amount of undegraded carbon-14 in the debris. You can identify the age of the animal. ..
After dating penguin bones and shells from more than 20 different coastlines, scientists discovered that about 5,500 years ago, the oldest and tallest beaches began to form. From that moment until about 30 years ago, researchers reported that the loss of ice exposed the coastline at a rate of about 0.14 inches (3.5 millimeters) each year. However, over the last three decades, coastline advance rates have skyrocketed to a maximum of 1.6 inches (40 mm) per year.
“These fragile glaciers have been relatively stable for the past few thousand years, but the current recession velocity is accelerating and is already raising the world’s sea level,” Ruud said.
It is unclear what this means for the future of Antarctic glaciers and ice sheets, and fragile coastlines around the world. The researchers’ findings are alarming, but they do not mention how many glaciers may have receded and re-advanced in recorded history. Scientists want to understand this by excavating ice and sampling the rocks of the land mass beneath it. This can indicate if the current melting rate is reversible or if the glacier has passed a truly non-returning point.
Originally published on Live Science.
Antarctica’s “Doomsday Glacier” is bleeding ice faster than in the last 5,500 years
Source link Antarctica’s “Doomsday Glacier” is bleeding ice faster than in the last 5,500 years