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Greenland Melted Recently, Shows High Risk of Sea Level Rise Today – UConn Today – today.uconn.edu

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During the Cold War, a secret U.S. Army mission, at Camp Century in northwestern Greenland, drilled down through 4,560 feet of ice on the frozen island—and then kept drilling, to pull out a 12-foot-long tube of soil and rock from below the ice. Then this icy sediment was lost in a freezer for decades. It was accidentally rediscovered in 2017 and shown to hold not just sediment but also leaves and moss, remnants of an ice-free landscape, perhaps a boreal forest.

But how long ago were those plants growing in an area that today is an ice sheet two miles thick and three times the size of Texas?

An international team of scientists, including UConn Earth Sciences Associate Professor Julie Fosdick, was amazed to discover that Greenland was a truly green land only 416,000 years ago (give or take about 38,000 years).

Their new study was published Thursday, July 20 in the journal Science.

‘Bulletproof Evidence’

Until recently, geologists believed that Greenland was a fortress of ice, mostly unmelted for millions of years. But, two years ago, using the rediscovered Camp Century ice core, this team of scientists showed that it likely melted less than one million years ago. Other scientists, working in central Greenland, gathered data showing the ice there melted at least once in the last 1.1 million years—but until this study, no one knew exactly when the ice was gone.

Now, using advanced luminescence technology and rare isotope analysis, the team has created a starker picture: large portions of Greenland’s ice sheet melted much more recently than a million years ago. The new study presents direct evidence that sediment just beneath the ice sheet was deposited by flowing water in an ice-free environment during a moderate warming period called Marine Isotope Stage 11, roughly from 424,000 to 374,000 years ago. This melting caused at least five feet of sea level rise around the globe, and potentially as much as 20 feet, says Fosdick.

Camp Century uppermost sample last exposed 416,000 years ago.
Camp Century uppermost sample last exposed 416,000 years ago (Photo courtesy of Andrew Christ / University of Vermont).

“It’s really the first bulletproof evidence that much of the Greenland ice sheet vanished when it got warm,” says University of Vermont geoscientist Paul Bierman, who co-led the new study with lead author Drew Christ, a post-doctoral geoscientist who worked in Bierman’s lab, Professor Tammy Rittenour from Utah State University, and 18 other scientists from around the world.

Understanding Greenland’s past is critical for predicting how its giant ice sheet will respond to climate warming in the future and how quickly it will melt. Since about 23 feet of sea-level rise is tied up in Greenland’s ice, every coastal region in the world is at risk. The new study provides strong and precise evidence that Greenland is more sensitive to climate change than previously understood—and at grave risk of irreversibly melting off.

“Greenland’s past, preserved in 12 feet of frozen soil, suggests a warm, wet, and largely ice-free future for planet Earth,” says Bierman, “unless we can dramatically lower the concentration of carbon dioxide in the atmosphere.”

Into the Light

At Rittenour’s lab, sediment from the Camp Century core was examined for what is called a “luminescence signal.” As bits of rock and sand are transported by wind or water, they can be exposed to sunlight—which, basically, zeros out any previous luminescence signal—and then re-buried under rock or ice. In the darkness, over time, minerals of quartz and feldspar in the sediment accumulate freed electrons in their crystals. In a specialized dark room, Rittenour’s team took pieces of the ice core sediment and exposed them to blue-green or infrared light, releasing the trapped electrons. With some advanced tools and measures, and many repeated tests, the number of released electrons forms a kind of clock, revealing with precision the last time these sediments were exposed to the sun.

These powerful new data were combined with insight from Bierman’s UVM lab. There, scientists study quartz from the Camp Century core. Inside this quartz, rare forms—called isotopes—of the elements beryllium and aluminum build up when the ground is exposed to the sky and can be hit by cosmic rays. Looking at ratios of beryllium and other isotopes gave the scientists a window into how long rocks at the surface were exposed vs. buried under layers of ice. This data helped the scientists show that the Camp Century sediment was exposed to the sky less than 14,000 years before it was deposited under the ice, narrowing down the time window when that portion of Greenland must have been ice-free.

Further evidence came from Fosdick’s research group, the Basin Analysis & Helium Thermochronology Lab at UConn, which led to the understanding of where the sediments came from through helium isotope analysis,

“We collect helium isotopes from the sediment that allow us to figure out how quickly or slowly those different sediments were eroded from the ancient Greenland hillslopes,” Fosdick says. “Our apatite tracer thermochronology data capture sources across a slowly eroding landscape within Archean crust.”

Fosdick explains that being able to assess the provenance, or source, of sediments is key because the sediments capture a picture of surface drainage across the northwestern Greenland landscape during this ice-free time. Now, most of Greenland is covered in ice, so there is very limited information on the geology underneath.

Camp Century fossil. Moss stem with intact leaves (Bryophyte), mosses are a key part of tundra ecosystems today. Camp Century fossil. Moss stem with intact leaves (Bryophyte), mosses are a key part of tundra ecosystems today.
Camp Century fossil. Moss stem with intact leaves (Bryophyte), mosses are a key part of tundra ecosystems today (Courtesy of Halley Mastro / University of Vermont).

“We’ve reconstructed what looks to be a vegetated and ice-free stream system, with flowing surface waters that existed 416,000 years ago,” Fosdick says.

Sea Level

Camp Century is 138 miles inland from the coast and only 800 miles from the North Pole; the new study shows that the region entirely melted and was covered with vegetation during Marine Isotope Stage 11, a long interglacial period with temperatures similar to, or slightly warmer than, today. With this information, the team’s models show that, during that period, the ice sheet melted enough to cause at least five feet, and perhaps as much as 20 feet, of sea-level rise. The research, supported by the U.S. National Science Foundation, lines up with findings from two other ice cores collected in 1990s from the center of Greenland. Sediment from these cores also suggests that the giant ice sheet melted in the recent geologic past. The combination of these earlier cores with the new insight from Camp Century reveal the fragile nature of the entire Greenland ice sheet—in the past (at 280 parts per million of atmospheric CO2 or less) and today (422 ppm and rising).

Fosdick says the data gives us valuable information for understanding the risks of future Greenland ice sheet melting and sea level rise in response to climate change today.

“The CO2 levels during Marine Isotope Stage 11 interglacial were lower than today, but warming was still sufficient to generate major Greenland ice sheet melting.”

“If we melt just portions of the Greenland ice sheet, the sea level rises dramatically,” says Rittenour. “Forward modeling the rates of melt, and the response to high carbon dioxide, we are looking at meters of sea level rise, probably tens of meters. And then look at the elevation of New York City, Boston, Miami, Amsterdam. Look at India and Africa—most global population centers are near sea level.”

“Four-hundred-thousand years ago there were no cities on the coast,” says Bierman, “and now there are cities on the coast.”

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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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