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.
We hypothesize that this damage preconditions these ice shelves for further disintegration. First, because it already compromises the integrity of both ice shelves. [4/n] pic.twitter.com/HqaPjg8OHv
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.”
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.
