Evidence from a 2,000-foot-long ice core reveals that the West Antarctic Ice Sheet shrank suddenly and dramatically around 8,000 years ago, according to new research — providing an alarming insight into how quickly Antarctic ice could melt and send sea levels soaring.
Part of the ice sheet thinned by 450 metres (1,476 feet) — a height greater than the Empire State Building — over a period of just 200 years at the end of the last Ice Age, according to the study published Wednesday in the journal Nature Geoscience.
It’s the first direct evidence that shows such a rapid loss of ice anywhere in Antarctica, according to the study’s authors.
While scientists knew the ice sheet was bigger at the end of the last Ice Age than today, much less was known about when exactly that shrinking happened, said Eric Wolff, a glaciologist at the University of Cambridge in the UK and a study author.
This study changes that, he told CNN. “We’ve been able to say exactly when it retreated, but we’ve also been able to say how fast it retreated.”
Now it’s clear the ice sheet retreated and thinned very rapidly in the past, Wolff said, the danger is that it could begin again. “If it does start to retreat, it really will do it very fast,” he added.
That could have catastrophic consequences for global sea level rise. The West Antarctic Ice Sheet holds enough water to raise sea levels by about 5 metres – more than 16 feet — which would cause devastating flooding in coastal towns and cities around the world.
The study is “an excellent piece of detective work” about a major part of the Antarctic ice sheet, said Ted Scambos, a glaciologist at the University of Colorado Boulder.
Inside the drilling tent at Skytrain Ice Rise, scientists preparing the drill for its next drop into the borehole. (University of Cambridge/British Antarctic Survey)
The key message is “the amount of ice stored in Antarctica can change very quickly — at a pace that would be hard to deal with for many coastal cities,” he told CNN.
Ice cores are historical archives of the Earth’s atmosphere. Made up of layers of ice that formed as snow fell and compacted over thousands of years, they contain bubbles of ancient air as well as contaminants that provide a record of environmental changes over millennia.
The ice core analyzed in the study was drilled from Skytrain Ice Rise located at the edge of the ice sheet, near the point where the ice starts to float and become part of the Ronne Ice Shelf.
Scientists extracted it in 2019, in a painstaking process that involved drilling constantly for 40 days, pulling up a thin cylinder of ice a few feet at a time. They then cut the core into sections, packed them in insulated boxes kept at minus 20 degrees Celsius, and sent them to the UK via plane then ship.
Once in the UK, the scientists measured the ice core’s water isotopes, which provide information on temperature in the past. Warmer temperatures indicate lower-lying ice — think of it like a mountain, Wolff said, the higher up you go the colder it gets.
They also measured the pressure of trapped air bubbles in the ice. Lower-lying and thinner ice contains higher pressure air bubbles.
It was a surprise when the data revealed just how quickly the ice had thinned at the end of the last Ice Age, Wolff said. “We actually spent a lot of time checking that we hadn’t made a mistake with the analysis.”
The West Antarctic Ice Sheet is particularly vulnerable to climate change, because the land under it is below sea level and slopes downward. When warm water gets underneath, it can melt very fast. “It can have a runaway process, and that’s evidently what happened 8,000 years ago,” Wolff said.
Insulated boxes full of ice cores being loaded into the Twin Otter aircraft, Skytrain Ice Rise, Antarctica. (Eric Wolff)
What makes the findings so alarming, said Isobel Rowell, an ice core scientist at the British Antarctic Survey and a study co-author, is that once that runaway happens “there’s really very little, if anything, that we can do to stop it,” she told CNN.
The crucial thing “is not to test it too far,” Wolff said, and that means tackling climate change. “We can avoid these tipping points still,” he said.
The new data will help improve the accuracy of the models scientists use to predict how the ice sheet will respond to future global heating, the report says.
David Thornalley, an ocean and climate scientist at University College London, said the study’s data was “striking.” He cautioned that as the study looked at a period 8,000 years ago, when climate conditions were different, the results aren’t a direct example of what could happen today. But, he added, they are still able to offer an “insight into the way that ice sheets can collapse.”
The study comes as scientists continue to sound the alarm about what is happening to the Earth’s most isolated continent.
For example, the Thwaites Glacier, also in West Antarctica, is melting rapidly. A 2022 study said the Thwaites — dubbed the Doomsday Glacier for the catastrophic impact its collapse would have on sea level rise — was hanging on “by its fingernails” as the planet warms.
This new study adds to these concerns, Scambos said. “(It) shows that the very same processes we are seeing just beginning now, in areas like Thwaites Glacier, have played out before in similar areas of Antarctica and indeed, the pace of ice loss was equal to our worst fears about a runaway ice loss.”
NAIROBI, Kenya (AP) — The body of Ugandan Olympic athlete Rebecca Cheptegei — who died after being set on fire by her partner in Kenya — was received Friday by family and anti-femicide crusaders, ahead of her burial a day later.
Cheptegei’s family met with dozens of activists Friday who had marched to the Moi Teaching and Referral Hospital’s morgue in the western city of Eldoret while chanting anti-femicide slogans.
She is the fourth female athlete to have been killed by her partner in Kenya in yet another case of gender-based violence in recent years.
Viola Cheptoo, the founder of Tirop Angels – an organization that was formed in honor of athlete Agnes Tirop, who was stabbed to death in 2021, said stakeholders need to ensure this is the last death of an athlete due to gender-based violence.
“We are here to say that enough is enough, we are tired of burying our sisters due to GBV,” she said.
It was a somber mood at the morgue as athletes and family members viewed Cheptegei’s body which sustained 80% of burns after she was doused with gasoline by her partner Dickson Ndiema. Ndiema sustained 30% burns on his body and later succumbed.
Ndiema and Cheptegei were said to have quarreled over a piece of land that the athlete bought in Kenya, according to a report filed by the local chief.
Cheptegei competed in the women’s marathon at the Paris Olympics less than a month before the attack. She finished in 44th place.
Cheptegei’s father, Joseph, said that the body will make a brief stop at their home in the Endebess area before proceeding to Bukwo in eastern Uganda for a night vigil and burial on Saturday.
“We are in the final part of giving my daughter the last respect,” a visibly distraught Joseph said.
He told reporters last week that Ndiema was stalking and threatening Cheptegei and the family had informed police.
Four in 10 women or an estimated 41% of dating or married Kenyan women have experienced physical or sexual violence perpetrated by their current or most recent partner, according to the Kenya Demographic and Health Survey 2022.
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.”
VICTORIA – The British Columbia government is partnering with a bear welfare group to reduce the number of bears being euthanized in the province.
Nicholas Scapillati, executive director of Grizzly Bear Foundation, said Monday that it comes after months-long discussions with the province on how to protect bears, with the goal to give the animals a “better and second chance at life in the wild.”
Scapillati said what’s exciting about the project is that the government is open to working with outside experts and the public.
“So, they’ll be working through Indigenous knowledge and scientific understanding, bringing in the latest techniques and training expertise from leading experts,” he said in an interview.
B.C. government data show conservation officers destroyed 603 black bears and 23 grizzly bears in 2023, while 154 black bears were killed by officers in the first six months of this year.
Scapillati said the group will publish a report with recommendations by next spring, while an independent oversight committee will be set up to review all bear encounters with conservation officers to provide advice to the government.
Environment Minister George Heyman said in a statement that they are looking for new ways to ensure conservation officers “have the trust of the communities they serve,” and the panel will make recommendations to enhance officer training and improve policies.
Lesley Fox, with the wildlife protection group The Fur-Bearers, said they’ve been calling for such a committee for decades.
“This move demonstrates the government is listening,” said Fox. “I suspect, because of the impending election, their listening skills are potentially a little sharper than they normally are.”
Fox said the partnership came from “a place of long frustration” as provincial conservation officers kill more than 500 black bears every year on average, and the public is “no longer tolerating this kind of approach.”
“I think that the conservation officer service and the B.C. government are aware they need to change, and certainly the public has been asking for it,” said Fox.
Fox said there’s a lot of optimism about the new partnership, but, as with any government, there will likely be a lot of red tape to get through.
“I think speed is going to be important, whether or not the committee has the ability to make change and make change relatively quickly without having to study an issue to death, ” said Fox.
This report by The Canadian Press was first published Sept. 9, 2024.
