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Antarctic Major

Two major Antarctic glaciers are tearing loose from their restraints, scientists say – The Washington Post

Two Antarctic glaciers that have long kept scientists awake at night are breaking free from the restraints that have hemmed them in, increasing the threat of large-scale sea-level rise.

Located along the coast of the Amundsen Sea in West Antarctica, the enormous Pine Island and Thwaites glaciers already contribute around 5 percent of global sea-level rise. The survival of Thwaites has been deemed so critical that the United States and Britain have launched a targeted multimillion-dollar research mission to the glacier. The loss of the glacier could trigger the broader collapse of the West Antarctic ice sheet, which contains enough ice to eventually raise seas by about 10 feet.

The new findings, published Monday in the Proceedings of the National Academy of Sciences, come from analysis of satellite images. They show that a naturally occurring buffer system that prevents the glaciers from flowing outward rapidly is breaking down, potentially unleashing far more ice into the sea in coming years.

The glaciers’ “shear margins,” where their floating ice shelves encounter high levels of friction that constrain the natural flow of ice, are progressively weakening and in some cases breaking into pieces.

“The stresses that slow down the glacier, they are no longer in place, so the glacier is speeding up,” said Stef Lhermitte, a satellite expert at Delft University of Technology in the Netherlands who led the new research along with colleagues from NASA and other research institutions in France, Belgium, Austria and the Netherlands.

While many of the images have been seen before, the new analysis suggests that they are a sign of further disintegration to come.

“We already knew that these were glaciers that might matter in the future, but these images to me indicate that these ice shelves are in a very bad state,” Lhermitte said.

It’s just the latest in a flurry of bad news about the planet’s ice.

Arctic sea ice is very close to — but likely to not quite reach — a record low for this time of year. Last month, Canada lost a large portion of its last major Arctic ice shelf.

And in Greenland, the largest still-intact ice shelf in the Northern Hemisphere, sometimes known as 79 North because of its latitude (its full name is Nioghalvfjerdsfjorden), just lost a large chunk of ice, equivalent in size to roughly two Manhattan islands, according to the Geological Survey of Denmark and Greenland. Experts there blamed the fracture on a strong general warming trend and temperatures that have been “incredibly” high in the northeast of Greenland in recent years.

Ice shelves are vast floating platforms that extend across the surface of the ocean at the outer edge of marine-based glaciers. As they flow over the water, these shelves freeze onto mountainsides and islands and anchor themselves to bumps in the seafloor. In this way, the shelves provide a braking mechanism on the natural outward flow of ice.

The buttressing effect occurs in the shear margins, where faster-flowing ice meets ice that is more static and stable, often because it is moored to some part of the landscape. In these places, the ice frequently crumples and contorts, a visible indication of the powerful stresses that it is under.

But when those stresses become too much, ice breaks. That’s what’s now happening in West Antarctica, the new research argues, suggesting that warm ocean water has thinned the ice shelves out enough from below that they became brittle.

At the same time, and for the same reason, the glaciers themselves began to flow outward faster. The resulting forces led the shear-margin ice to break into pieces — which means that the glacier, less constrained, will now be able to add ice to the ocean even faster.

For the Pine Island Glacier, the new study finds that while the cracking and fraying at the shear margin dates to 1999, it accelerated in 2016. Here’s a video based on images from the European Space Agency’s Sentinel satellite, showing the changes in the past four years:

Even more concerning is the Thwaites Glacier. Here, again, the breakdown of the shear margin has increased in recent years:

“This is important work,” Richard Alley, a glaciologist at Pennsylvania State University, said of the new study.

Alley noted that the processes playing out in Antarctica appear to have already reached their completion in parts of Greenland, where one of the largest glaciers, Jakobshavn, no longer has any significant ice shelf at all. When it lost that shelf around the year 2000, Jakobshavn’s rate of ice loss steeply increased.

The 79 North glacier still has a major ice shelf, as do some of Greenland’s other northernmost glaciers, but many of these have lost considerable size in recent decades.

“The new paper shows that the Amundsen Sea Embayment ice shelves have gone through most, but not all, of the Jakobshavn steps,” Alley said in an email. “[A] warming ocean thinned the ice shelves, this reduced buttressing, this let the non-floating ice move faster, contributing some to sea-level rise and also starting to break the sides of the ice shelves, but additional acceleration could occur if the rest of the steps (further fracture and ice-shelf loss) should occur.”

Multiple ice-shelf collapses have already been seen in Canada, Greenland and the warmer Antarctic Peninsula, where the onetime Larsen A and Larsen B ice shelves fractured and, today, no longer exist.

“When the ice shelves are damaged by climate change, as we saw in the Antarctic Peninsula in the last several decades, their buttressing effect is reduced and the ice streams speed up and raise sea levels,” said Isabella Velicogna, a glaciologist at the University of California at Irvine, commenting on the new study. “The speed-up increases damage, a positive feedback which is not good news.”

If a similar process plays out in the Amundsen Sea of West Antarctica, where Pine Island and Thwaites are, the sea-level consequences could be enormous.

Lhermitte provided calculations showing that over the past six years, the western and central parts of the Pine Island ice shelf have shrunk by about 30 percent, from about 1,500 square miles down to closer to 1,000 square miles. In other words, an area about the size of Los Angeles has been lost.

“This shear margin is so damaged we think it preconditions this ice shelf for destabilization on the longer term,” Lhermitte said. “These are the first signs we see that Pine Island ice shelf is disappearing. This damage is difficult to heal.”

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Galaxy Major

Major Galaxy Tab S7 leak hints at a smaller model without AMOLED – Engadget

Performance, at least, would be similar. Both Tab S7 models reportedly boast Snapdragon 865 Plus processors, optional 5G models, a minimum 6GB of RAM and 128GB or more of expandable storage. You could also expect 13MP main and 5MP ultra-wide rear cameras and very low latency S-Pens much like those rumored for the Galaxy Note 20.

Samsung may also be closer to fulfilling its dreams of turning the Galaxy Tab into a PC replacement. Both tablets might support a Wireless DeX feature that saves you from having to plug in for desktop use. If you don’t need external peripherals, the keyboard cover will supposedly have a larger trackpad and full-size keys.

Images of the tablet suggest the design won’t change. Both slates would have flat metal edges and screens that hug the bezels.

It’s not certain how much the new tablets would cost or how soon they might be available after Unpacked. The Tab S6 started at $649, but it also came with a 10.5-inch AMOLED screen. The switch to LCD could affect the pricing, although we wouldn’t count on a price drop.

All products recommended by Engadget are selected by our editorial team, independent of our parent company. Some of our stories include affiliate links. If you buy something through one of these links, we may earn an affiliate commission.

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Major Petroleum

Major Petroleum Spill Spreads Toward Arctic Ocean in Russia’s North – The New York Times

Europe|Major Petroleum Spill Spreads Toward Arctic Ocean in Russia’s North

A diesel fuel spill in Russia’s far north has released about half as much petroleum into the environment as the Exxon Valdez tanker accident in Alaska. The fuel is flowing toward the Arctic Ocean.

Credit…Planet Labs Inc./Agence France-Presse — Getty Images

Andrew E. Kramer

MOSCOW — Floating barriers hastily laid across rivers in the far north of Russia have failed to contain a major diesel fuel spill that has now spread to a lake near the Arctic Ocean and is threatening a nature reserve, a regional governor said Tuesday.

The environmental disaster is unfolding far to the north of the Arctic Circle, in a marshy wilderness near the isolated mining city of Norilsk.

Diesel fuel spilled from a tank that burst last week after settling into permafrost that had stood firm for years but gave way during a warm spring, Russian officials said.

The accident, which environmental groups have compared to the Exxon Valdez tanker spill in Alaska in 1989, has highlighted the risks of industrial development in the thawing Arctic, where climate change is warming the environment at a rate about twice as fast as the rest of the Earth.

The spill released about 150,000 barrels of diesel into a river, compared with about 260,000 barrels of crude oil released into Prince William Sound during the Exxon tanker accident, a touchstone for environmental damage from petroleum spills.

The diesel has been seeping into the marshy riverbanks and spreading as an iridescent sheen on the surface of rivers. A frantic effort to lay booms, or floating barriers, across the rivers has not contained the spill.

By Tuesday, fuel was found in a 43-mile-long finger lake called Pyasino, which stretches toward the Arctic Ocean, Aleksandr Uss, the governor of the Krasnoyarsk region, told local media.

Image

Credit…Vasiliy Ryabinin, via Associated Press

“It’s a marvelous lake,” he said. “Naturally, there are fish there and a good natural environment. But it’s impossible to predict how it will hold up now.”

Mr. Uss said the cleanup would now focus on containing the diesel fuel in the lake by preventing it from flowing into the Pyasino River, which drains through a nature reserve into the Arctic Ocean. He said, “I think this will be possible.”

President Vladimir V. Putin last week declared a state of emergency in the remote region in northern Siberia after it became clear the spill, which occurred on May 29, would not be contained near the site of the ruptured tank.

The accident is one of the largest petroleum spills in modern Russian history, according to WWF, a conservation group. “We are talking about dead fish, polluted plumage of birds and poisoned animals,” Sergey Verkhovets, coordinator of Arctic projects for WWF Russia, said in a statement.

Prosecutors arrested the manager of the power plant that operated the tank. That plant provides electricity to one of the largest industrial developments above the Arctic Circle, the Norilsk Nickel mines and metal smelters.

The sprawl of factories, originally built by slave laborers in the gulag under Stalin, produces about a fifth of the world’s nickel, and half of the world’s palladium, a precious metal used in pollution-controlling catalytic converters on car exhaust pipes.

The factories are significant polluters of the Arctic environment. Smokestacks belch so much sulfur dioxide, a cause of acid rain, that the town is surrounded by a dead zone of tree trunks and mud about twice the size of Rhode Island. The company has dispatched hundreds of workers to help clean the spilled diesel.

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