Canadian scientist examines melting Antarctic glacier, potential sea level rise - Globalnews.ca | Canada News Media
Connect with us

Science

Canadian scientist examines melting Antarctic glacier, potential sea level rise – Globalnews.ca

Published

 on


As icebergs drifted by his Antarctica-bound ship, David Holland spoke this week of how the melting glacier he’s cruising towards may contain warning signals for the coasts of far-off Canada.

The atmospheric and ocean scientist from Newfoundland is part of an expedition to one of the world’s most frigid and remote spots – the Thwaites glacier in the western portion of the continent – where he’ll measure water temperatures in an undersea channel the size of Manhattan.

“The question of whether sea level will change can only be answered by looking at the planet where it matters, and that is at Thwaites,” said Holland, director of the environmental fluid dynamics laboratory at New York University, during a satellite phone interview from aboard the South Korean icebreaker Araon.

Read more:

‘Historic’ Halifax seawall being redeveloped as municipality seeks to reduce impact of climate change

It’s over 16,000 kilometres from Holland’s hometown in Brigus, N.L., on Conception Bay, to the site about 100 kilometres inland from the “grounding zone” where the Thwaites’ glacier leaves the continent and extends over the Pacific.

The team’s 20,000 tonnes of drilling gear will be assembled to measure the temperatures, salinity and turbulence of the Pacific waters that have crept underneath and are lapping away at the guts of the glacier.

“If it (the water) is above freezing, and in salt water this means above -2 centigrade, that’s not sustainable. A glacier can’t survive that,” said Holland.

Since 2018, more than 60 scientists from the International Thwaites Glacier Collaboration group have been exploring the ocean and marine sediments, measuring warming currents flowing toward the deep ice, and examining the stretching, bending, and grinding of the glacier over the landscape below.

The Florida-sized Thwaites glacier faces the Amundsen Sea, and researchers have suggested in journal articles over the past decade it may eventually lose large amounts of ice because of deep, warm water driven into the area as the planet warms. Some media have dubbed Thwaites the “doomsday glacier” due to estimates that it could add about 65 centimetres to global sea level rise.

Holland notes current research models mainly suggest this would happen over several centuries, however there are also lower probability theories of “catastrophic collapse” occurring, where the massive ice shelf melts in the space of decades. “We want to pay attention to things that are plausible, and rapid collapse of that glacier is a possibility,” he said.

While Holland looks at the undersea melting, other scientists are examining how the land-based portions of Antarctic glaciers are losing their grip on points of attachment to the seabed, potentially causing parts to detach. Still other researchers point to the risk of initial fractures causing the ice shelf to break, much like a damaged car windshield.

Read more:

Seawall damage a sign of things to come amid sea level rise and climate change, experts warn

All of the mechanisms must be carefully observed to prove or disprove models on the rates of melting, said Holland.

“If the (water-filled) cave beneath the glacier we’re studying gets bigger, then Antarctica is losing ice and retreating, and if the cave collapses on itself, then (the cave) will disappear. This is how Antarctica can retreat, these kinds of specific events,” he said.

The implications of the glacier work reach back to Atlantic Canada – which along with communities along the Beaufort Sea and in southwestern British Columbia is the region most vulnerable to sea level rise in the country, according to federal scientists.

Everything from how to calculate the future height of dikes at the low-lying Chignecto Isthmus – the narrow band of land that connects Nova Scotia to the rest of the country – to whether the Fraser River lowlands may face flooding is potentially affected by glacial melting in Antarctica, he said.

Scenarios where Antarctica ice melts more quickly than expected are briefly discussed in the 2019 federal report Canada’s Changing Climate. Based largely on Intergovernmental Panel on Climate Change reports that refer to them as low-probability “tipping point” theories, the 2019 report invoked the possibility of one metre of sea level rise by 2100.

However, Blair Greenan, a federal oceanographer who oversaw the relevant chapter of the report, said in a recent interview that a rise in global sea levels approaching two metres by 2100 and five metres by 2150 “cannot be ruled out” due to uncertainty over ice sheet processes like Thwaites.

“We don’t know, nobody knows,” Holland said. “But it’s plausible these things can change, and several feet of sea level change would have a major impact on Atlantic Canada. What’s needed is glacier forecasting that resembles the kinds of accuracy that weather forecasting currently provides.”






1:44
Why some people are ‘migrating’ because of climate change


Why some people are ‘migrating’ because of climate change – Jan 14, 2022

However, collecting glacier forecast data is a daunting undertaking in the short period – from late January until mid-February – when scientists can safely take readings. Helicopters will be ferrying a hot water drill, 30 barrels of fuel and water to Holland’s site beginning near the end of January. The drill will have to penetrate over a kilometre of ice to reach the 300 metres of undersea channel to take measurements.

As the data is collected, some scientists question whether there’s really much for Canadian coastal residents to worry about at this stage.

One study by Ian Joughin, a University of Washington glaciologist, has suggested Thwaites will only lose ice at a rate that creates sea level rise of one millimetre per year – and not until next century. At that rate it would take 100 years for sea levels to rise 10 centimetres.

In a telephone interview last week, Joughin said planning coastal protection and other measures for the more extreme scenarios may not be cost effective at this point, as it may take up to a century before the major risks starts to unfold.

However, Joanna Eyquem, a Montreal-based geoscientist who is studying ways to prepare infrastructure for rising sea levels, said in a recent email that glacier research shows sea level forecasts “are constantly evolving,” and adaptation efforts need to be quicker.

“The question is: How desperate does the situation need to be before we take action?” she asked.

This report by The Canadian Press was first published Jan. 23, 2022.

© 2022 The Canadian Press

Adblock test (Why?)



Source link

Continue Reading

News

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

Published

 on

 

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. ”

___

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

___

Follow Seth Borenstein on Twitter at @borenbears

___

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.

Source link

Continue Reading

Science

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

Published

 on

 

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.

Source link

Continue Reading

News

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

Published

 on

 

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.

Source link

Continue Reading

Trending

Exit mobile version