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Ice shelves propping up two major Antarctic glaciers are breaking up – CTV News

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Satellite images show that two important glaciers in the Antarctic are sustaining rapid damage at their most vulnerable points, leading to the breaking up of vital ice shelves with major consequences for global sea level rise.

The Pine Island and Thwaites glaciers, which sit side by side in West Antarctica on the Amundsen Sea, are among the fastest changing glaciers in the region, already accounting for 5% of global sea level rise. Scientists say the glaciers are highly sensitive to climate change.

A new study, published in the Proceedings of the National Academy of Sciences on Monday, found that the glaciers are weakening at their foundations and this damage over the past few decades is speeding up their retreat and the possible future collapse of their ice shelves.

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

While rapid ice loss and melt of these Antarctic glaciers have been well documented, the new study suggests there could be future disintegration of the ice shelves to come.

“We knew they were sleeping giants and these were the ones losing a lot of miles (of ice), but how far and how much still remains a large uncertainty,” Lhermitte said. “These ice shelves are in the early phase of disintegration, they’re starting to tear apart.”

Thwaites Glacier is one of the largest and most unstable ice streams in Antarctica. It’s a giant mass of more than 192,000 square kilometers (74,000 square miles) — an area similar in size to the US state of Florida, or Great Britain.

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

So what’s happening to the glaciers now?

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

This ocean warming has increased the melting and calving (the breaking off of ice chunks) of Pine Island and Thwaites glaciers, studies show, while declining of snowfall means the glaciers can’t replenish themselves.

The damage researchers found pointed to a weakening of the glaciers’ shear margins — areas at the edges of the floating ice shelf where the fast moving ice meets the slower moving ice or rock underneath.

“Typically the ice shelf acts like slow traffic. It’s floating on the ocean but it buttresses the ice traffic behind it,” Lhermitte said. “So if you weaken this slow car, then the ice discharges more rapidly.”

That’s exactly what the researchers observed — and they believe these severely weakening parts of the glacier will accelerate mass ice loss. The study makes the case that this process should be included in models that project sea level rise, which it’s not currently a part of.

Researchers found that while the tearing of Pine Island Glacier’s shear margins has been documented since 1999, their satellite imagery shows that damage sped up dramatically in 2016.

Similarly, the damage to Thwaites Glacier began moving further upstream in 2016 and fractures rapidly started opening up near the glacier’s grounding line, which is where the ice meets the rock bed.

Researchers warn the process is creating a feedback loop — where the weakening ice shelf is speeding up the damage to the glacier’s vulnerable shear margins, which in turn leads to more damage and disintegration of the ice shelf.

Isabella Velicogna, Professor of Earth System Sciences at the University of California Irvine, who wasn’t involved in the study, said that, “with a process of weakening of the ice shelf included in models, it is likely that the glacier speed up will occur sooner and will be larger in magnitude, which means that sea level will rise faster than currently projected.”

Velicogna said that there are other processes that play “a much larger role” in glacier evolution, such as “the rate of retreat of the grounding line forced by a warmer ocean.”

Glaciers in trouble

The study comes on the heels of research published last week that found deep channels under the Thwaites Glacier may be allowing warm ocean water to melt the underside of its ice.

The cavities hidden beneath the ice shelf are likely to be the route through which warm ocean water passes underneath the ice shelf up to the grounding line, they said.

Over the past three decades, the rate of ice loss from Thwaites and its neighboring glaciers has increased more than five-fold. If Thwaites were to collapse, it could lead to an increase in sea levels of around 25 inches (64 centimeters).

And there’s more bad news for glaciers on the other side of the world. On Monday, scientists announced that a 44-square-mile chunk of ice, about twice the size of Manhattan, has broken off the Arctic’s largest remaining ice shelf in northeast Greenland in the past two years, raising fears of its rapid disintegration.

The territory’s ice sheet is the second biggest in the world behind Antarctica’s, and its annual melt contributes more than a millimeter rise to sea levels every year.

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

“Most of the weakening in this part of Antarctica is coming from below,” he said. “Warm ocean water gets to the (glaciers’) base and weakens them. What we observed is that this becomes so weakened, that they speed up and once they speed up, the shear margins speed up and start to break.”

Velicogna said the research “points to another Achilles’ heel of the system conducive to faster retreat, and triggered by climate change.”

“It seems that the more we look at these systems evolve, the more we see reasons for them to disappear more rapidly than we thought,” she said. “We have to act quickly on controlling climate change to preserve our future. The time to act is now.”

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Here’s how Helene and other storms dumped a whopping 40 trillion gallons of rain on the South

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More than 40 trillion gallons of rain drenched the Southeast United States in the last week from Hurricane Helene and a run-of-the-mill rainstorm that sloshed in ahead of it — an unheard of amount of water that has stunned experts.

That’s enough to fill the Dallas Cowboys’ stadium 51,000 times, or Lake Tahoe just once. If it was concentrated just on the state of North Carolina that much water would be 3.5 feet deep (more than 1 meter). It’s enough to fill more than 60 million Olympic-size swimming pools.

“That’s an astronomical amount of precipitation,” said Ed Clark, head of the National Oceanic and Atmospheric Administration’s National Water Center in Tuscaloosa, Alabama. “I have not seen something in my 25 years of working at the weather service that is this geographically large of an extent and the sheer volume of water that fell from the sky.”

The flood damage from the rain is apocalyptic, meteorologists said. More than 100 people are dead, according to officials.

Private meteorologist Ryan Maue, a former NOAA chief scientist, calculated the amount of rain, using precipitation measurements made in 2.5-mile-by-2.5 mile grids as measured by satellites and ground observations. He came up with 40 trillion gallons through Sunday for the eastern United States, with 20 trillion gallons of that hitting just Georgia, Tennessee, the Carolinas and Florida from Hurricane Helene.

Clark did the calculations independently and said the 40 trillion gallon figure (151 trillion liters) is about right and, if anything, conservative. Maue said maybe 1 to 2 trillion more gallons of rain had fallen, much if it in Virginia, since his calculations.

Clark, who spends much of his work on issues of shrinking western water supplies, said to put the amount of rain in perspective, it’s more than twice the combined amount of water stored by two key Colorado River basin reservoirs: Lake Powell and Lake Mead.

Several meteorologists said this was a combination of two, maybe three storm systems. Before Helene struck, rain had fallen heavily for days because a low pressure system had “cut off” from the jet stream — which moves weather systems along west to east — and stalled over the Southeast. That funneled plenty of warm water from the Gulf of Mexico. And a storm that fell just short of named status parked along North Carolina’s Atlantic coast, dumping as much as 20 inches of rain, said North Carolina state climatologist Kathie Dello.

Then add Helene, one of the largest storms in the last couple decades and one that held plenty of rain because it was young and moved fast before it hit the Appalachians, said University of Albany hurricane expert Kristen Corbosiero.

“It was not just a perfect storm, but it was a combination of multiple storms that that led to the enormous amount of rain,” Maue said. “That collected at high elevation, we’re talking 3,000 to 6000 feet. And when you drop trillions of gallons on a mountain, that has to go down.”

The fact that these storms hit the mountains made everything worse, and not just because of runoff. The interaction between the mountains and the storm systems wrings more moisture out of the air, Clark, Maue and Corbosiero said.

North Carolina weather officials said their top measurement total was 31.33 inches in the tiny town of Busick. Mount Mitchell also got more than 2 feet of rainfall.

Before 2017’s Hurricane Harvey, “I said to our colleagues, you know, I never thought in my career that we would measure rainfall in feet,” Clark said. “And after Harvey, Florence, the more isolated events in eastern Kentucky, portions of South Dakota. We’re seeing events year in and year out where we are measuring rainfall in feet.”

Storms are getting wetter as the climate change s, said Corbosiero and Dello. A basic law of physics says the air holds nearly 4% more moisture for every degree Fahrenheit warmer (7% for every degree Celsius) and the world has warmed more than 2 degrees (1.2 degrees Celsius) since pre-industrial times.

Corbosiero said meteorologists are vigorously debating how much of Helene is due to worsening climate change and how much is random.

For Dello, the “fingerprints of climate change” were clear.

“We’ve seen tropical storm impacts in western North Carolina. But these storms are wetter and these storms are warmer. And there would have been a time when a tropical storm would have been heading toward North Carolina and would have caused some rain and some damage, but not apocalyptic destruction. ”

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Follow AP’s climate coverage at https://apnews.com/hub/climate

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Follow Seth Borenstein on Twitter at @borenbears

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Associated Press climate and environmental coverage receives support from several private foundations. See more about AP’s climate initiative here. The AP is solely responsible for all content.

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‘Big Sam’: Paleontologists unearth giant skull of Pachyrhinosaurus in Alberta

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It’s a dinosaur that roamed Alberta’s badlands more than 70 million years ago, sporting a big, bumpy, bony head the size of a baby elephant.

On Wednesday, paleontologists near Grande Prairie pulled its 272-kilogram skull from the ground.

They call it “Big Sam.”

The adult Pachyrhinosaurus is the second plant-eating dinosaur to be unearthed from a dense bonebed belonging to a herd that died together on the edge of a valley that now sits 450 kilometres northwest of Edmonton.

It didn’t die alone.

“We have hundreds of juvenile bones in the bonebed, so we know that there are many babies and some adults among all of the big adults,” Emily Bamforth, a paleontologist with the nearby Philip J. Currie Dinosaur Museum, said in an interview on the way to the dig site.

She described the horned Pachyrhinosaurus as “the smaller, older cousin of the triceratops.”

“This species of dinosaur is endemic to the Grand Prairie area, so it’s found here and nowhere else in the world. They are … kind of about the size of an Indian elephant and a rhino,” she added.

The head alone, she said, is about the size of a baby elephant.

The discovery was a long time coming.

The bonebed was first discovered by a high school teacher out for a walk about 50 years ago. It took the teacher a decade to get anyone from southern Alberta to come to take a look.

“At the time, sort of in the ’70s and ’80s, paleontology in northern Alberta was virtually unknown,” said Bamforth.

When paleontogists eventually got to the site, Bamforth said, they learned “it’s actually one of the densest dinosaur bonebeds in North America.”

“It contains about 100 to 300 bones per square metre,” she said.

Paleontologists have been at the site sporadically ever since, combing through bones belonging to turtles, dinosaurs and lizards. Sixteen years ago, they discovered a large skull of an approximately 30-year-old Pachyrhinosaurus, which is now at the museum.

About a year ago, they found the second adult: Big Sam.

Bamforth said both dinosaurs are believed to have been the elders in the herd.

“Their distinguishing feature is that, instead of having a horn on their nose like a triceratops, they had this big, bony bump called a boss. And they have big, bony bumps over their eyes as well,” she said.

“It makes them look a little strange. It’s the one dinosaur that if you find it, it’s the only possible thing it can be.”

The genders of the two adults are unknown.

Bamforth said the extraction was difficult because Big Sam was intertwined in a cluster of about 300 other bones.

The skull was found upside down, “as if the animal was lying on its back,” but was well preserved, she said.

She said the excavation process involved putting plaster on the skull and wooden planks around if for stability. From there, it was lifted out — very carefully — with a crane, and was to be shipped on a trolley to the museum for study.

“I have extracted skulls in the past. This is probably the biggest one I’ve ever done though,” said Bamforth.

“It’s pretty exciting.”

This report by The Canadian Press was first published Sept. 25, 2024.

The Canadian Press. All rights reserved.

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The ancient jar smashed by a 4-year-old is back on display at an Israeli museum after repair

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TEL AVIV, Israel (AP) — A rare Bronze-Era jar accidentally smashed by a 4-year-old visiting a museum was back on display Wednesday after restoration experts were able to carefully piece the artifact back together.

Last month, a family from northern Israel was visiting the museum when their youngest son tipped over the jar, which smashed into pieces.

Alex Geller, the boy’s father, said his son — the youngest of three — is exceptionally curious, and that the moment he heard the crash, “please let that not be my child” was the first thought that raced through his head.

The jar has been on display at the Hecht Museum in Haifa for 35 years. It was one of the only containers of its size and from that period still complete when it was discovered.

The Bronze Age jar is one of many artifacts exhibited out in the open, part of the Hecht Museum’s vision of letting visitors explore history without glass barriers, said Inbal Rivlin, the director of the museum, which is associated with Haifa University in northern Israel.

It was likely used to hold wine or oil, and dates back to between 2200 and 1500 B.C.

Rivlin and the museum decided to turn the moment, which captured international attention, into a teaching moment, inviting the Geller family back for a special visit and hands-on activity to illustrate the restoration process.

Rivlin added that the incident provided a welcome distraction from the ongoing war in Gaza. “Well, he’s just a kid. So I think that somehow it touches the heart of the people in Israel and around the world,“ said Rivlin.

Roee Shafir, a restoration expert at the museum, said the repairs would be fairly simple, as the pieces were from a single, complete jar. Archaeologists often face the more daunting task of sifting through piles of shards from multiple objects and trying to piece them together.

Experts used 3D technology, hi-resolution videos, and special glue to painstakingly reconstruct the large jar.

Less than two weeks after it broke, the jar went back on display at the museum. The gluing process left small hairline cracks, and a few pieces are missing, but the jar’s impressive size remains.

The only noticeable difference in the exhibit was a new sign reading “please don’t touch.”

The Canadian Press. All rights reserved.

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