Home https://server7.kproxy.com/servlet/redirect.srv/sruj/smyrwpoii/p2/ Science https://server7.kproxy.com/servlet/redirect.srv/sruj/smyrwpoii/p2/ The demolition of the shelf in Antarctica may be inevitable as they have been melting too fast over 300 years

The demolition of the shelf in Antarctica may be inevitable as they have been melting too fast over 300 years



A special issue of Nature publishes a series of studies examining how monitoring of Antarctica from space provides a decisive picture of its response to the warming climate.

Here are their main findings:

Three trillion tons of ice lost in Antarctica since 1992

The Antarctic ice sheet lost about three trillion tons of ice between 1992 and 2017, according to research led by the University of Leeds.

This figure corresponds to an average sea level rise of about eight millimeters (1/3 inch), with two-fifths of this rise occurring only in the last five years.

found that people in coastal communities were more at risk of losing their homes and becoming so-called climate refugees than they had previously feared.

In one of the most complete photographs of the ice change in Antarctica to date, an international team of 84 experts 24 satellite studies to give results.

By 201

2, Antarctica was found to be losing ice at a steady rate of 76 billion tons per year, contributing 0.2 mm (0.008 inches) per year to sea level rise.

However, there has been a sharp, threefold increase since then.

At one point in the last ice age, the West Antarctic Ice Sheet is smaller than it is today.

Researchers earlier believe that, since the last Ice Age, about 15,000 years ago, the West Antarctic Ice leaf (WAIS) is getting smaller

New research published by the University of Northern Illinois shows that about 14,500 and 9,000 years ago, ice cover below sea level was even smaller than it is today.

After thousands of years, the loss of the huge amount of ice that previously weighed down the seabed caused a rise in the seabed.

Then the ice roof began to recover to today's configuration.

"Today, WAIS is retiring again. , but there has been a time since the last ice age when the ice sheet was even smaller than it is now, but it has not yet collapsed, "said University of Northern Illinois Geology professor Reid Scherer, lead author of the study.

– This is important there is no information to have as we try to figure out how the ice sheet will behave in the future, "he said.

The East Antarctic ice sheet has been stable over the last warm period

The stability of the largest ice roof on Earth is an indication that scientists can withstand as temperatures continue to rise. [19659002] If all of Antarctica's ice sheet melts, sea level will rise by 175 feet (53 meters).

However, unlike the icy areas of Greenland and Western Antarctica, it seems that it would be resistant to melting because the conditions are warm, according to studies by Purdue University and Boston College.

Their studies show that the eastern Antarctic ice sheets are mostly stable during the Pliocene (5.3 to 2.6 million years ago).

This is when the concentrations of carbon dioxide in the atmosphere are close to what they are today – about 400 parts per million.

"Based on this evidence from the Pliocene, today's carbon dioxide levels are not enough to destabilize Antarctica ontinent ground ice," said Jeremy Shakun, lead author of the report and associate professor of earth and environmental science at Boston College .

"This does not mean that, at present atmospheric levels of carbon dioxide, Antarctica will not contribute to sea level rise.

"The sea-based ice could very well and in fact is already beginning to contribute, and this alone keeps an approximately 20-meter rise at sea level," he said.

Decisions over the next decade will determine whether Antarctica contributes a meter to sea level rise

One of the biggest uncertainties in future forecasts for sea level rise is how the ice of Antarctica responds to the challenge human global warming.

Scientists say time is running out to save this unique ecosystem and if the right decisions are not made in the next ten years, there will be no going back.

Researchers at Imperial College London have evaluated the state of Antarctica in 2070 at two scenarios that

Antarctica and the Southern Ocean underwent broad and rapid change with global implications in the narrative of high emissions and low regulations.

By 2070, the warming of the ocean and atmosphere has caused dramatic loss of large ice shelves, leading to increased loss of ground ice from the Antarctic Ice Sheet and accelerating global sea level rise.

According to low emissions and stringent regulations, reducing greenhouse gas emissions and implementing effective policies help minimize changes in Antarctica, which in 2070 is much like in the first decades of the century.

This causes the Antarctic ice shelves to remain intact, delaying the loss of ice from the ice sheet and reducing the threat of rising sea levels. What Saved the Western Antarctic Ice Sheet 10,000 Years Ago Will Not Save It Today

Scientists' retreat discovered the surprisingly icy masses of Western Antarctica after the last glacial age about 10,000 years ago. .

In fact, it was the contraction that stopped the contraction: released from the weight of the ice, the earth's crust rose and triggered the restoration of the ice sheet.

According to research by the Potsdam Institute for Climate Impact Research (PIK), this mechanism is very slow to prevent the dangerous sea level rise caused by the loss of ice in Western Antarctica in the present and in the near future.

Researchers found only a rapid reduction in greenhouse gas emissions.

"Warming after the last ice age has caused the ice masses of western Antarctica to decrease," says Thorsten Albrecht of the Potsdam Institute for Climate Impact Research. .

"Given the speed of current climate change from burning fossil fuels, the mechanism we found is unfortunately not working fast enough to save today's ice sheets from melting and lead to rising seas." [19659040] Ice shelves in the world can be destabilized by forces from above and below

Researchers have found that warm ocean water flowing into channels beneath the Antarctic ice shelves thickens the ice below so much that the ice in the channels cracks .

Subsequently, surface molten water can flow into these fractures, further destabilizing the ice shelf and increasing the chances that significant pieces will break away.

Researchers led by the University of Texas at Austin document this mechanism in the case of major ice breakage or calving in the Nansen Ice Shelf in Antarctica.

Conclusions are concerned because ice shelves are floating extensions of Continental glaciers slow the flow of ice into the ocean and help

"We learn that ice racks are more vulnerable to rising ocean and air temperatures than we thought," says Professor Christine Doe, lead author of the study.

"Dual processes occur here. One that is destabilized from below and the other from above.

"This information could have an impact on our estimated shelf life and the resulting sea-level rise due to climate change," he said.


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