For researchers attempting to anticipate the global sea level rise rate, the Thwaites Glacier in West Antarctica, which is about the size of Florida, has been a significant sticking point.
The R/V Nathaniel B. Palmer was photographed from a drone at Thwaites Glacier ice front in February 2019. Image Credit: Alexandra Mazur/University of Gothenburg
When seen in geological periods, this vast ice stream is already in a stage of rapid retreat, known as a “collapse,” which has raised many questions about how much ice it will eventually lose to the ocean and how quickly.
The effects of Thwaites’ retreat might be terrifying: if the glacier and its surrounding glacial basins vanish entirely, the sea level could rise by three to ten feet.
The concern is increased by a recent study published in Nature Geoscience headed by marine geophysicist Alastair Graham of the College of Marine Science at the University of South Florida.
The seafloor in front of the glacier was crucially imaged in high resolution for the first time, providing researchers with a window into how quickly Thwaites advanced and receded in the past.
The breathtaking footage offers a kind of crystal ball to look into Thwaites’ future and reveals geologic aspects that are new to science. Understanding previous behavior is essential to predicting future behavior in humans and ice sheets.
The crew recorded more than 160 parallel ridges left behind when the glacier’s front edge retreated and oscillated with the daily tides.
It’s as if you are looking at a tide gauge on the seafloor. It blows my mind how beautiful the data are.
Alastair Graham, Marine Geophysicist, College of Marine Science, University of South Florida
Graham added that despite its beauty, Thwaites is troubling because the rate of retreat scientists have lately discovered is slow compared to the quickest rates of change in its past.
The scientists examined the rib-like structures 700 m (just under half a mile) beneath the Arctic Ocean to comprehend Thwaites’ previous retreat. They also considered the region’s tidal cycle, as anticipated by computer models, to demonstrate that one rib must have developed each day.
Related Stories
The front of the glacier lost contact with a ridge on the seafloor somewhere in the past 200 years, and for a period of fewer than six months, it retreated at a rate of more than 2.1 km per year (1.3 miles per year), which is twice the rate observed by satellites between 2011 and 2019.
“Our results suggest that pulses of very rapid retreat have occurred at Thwaites Glacier in the last two centuries, and possibly as recently as the mid-20th Century,” Graham said.
“Thwaites is holding on today by its fingernails, and we should expect to see big changes over small timescales in the future–even from one year to the next–once the glacier retreats beyond a shallow ridge in its bed,” said Robert Larter, a marine geophysicist and study co-author of the British Antarctic Survey.
The team, which includes researchers from the United States, the United Kingdom, and Sweden, deployed a cutting-edge orange robotic vehicle dubbed “Rán” from the R/V Nathaniel B. Palmer during an expedition in 2019 to gather the imagery and accompanying geophysical data.
According to Graham, Rán—run by researchers at the University of Gothenburg in Sweden—set off on a 20-hour journey that was both dangerous and fortunate. It did so in harsh conditions during an extraordinary summer remarkable for its absence of sea ice, mapping a region of the seabed in front of the glacier about the size of Houston.
This made it possible for scientists to reach the glacier front for the first time.
“This was a pioneering study of the ocean floor, made possible by recent technological advancements in autonomous ocean mapping and a bold decision by the Wallenberg foundation to invest in this research infrastructure,” said Anna Wåhlin, a physical oceanographer from the University of Gothenburg who deployed Rán at Thwaites.
“The images Ran collected to give us vital insights into the processes happening at the critical junction between the glacier and the ocean today,” Wåhlin said.
It was truly a once-in-a-lifetime mission.
Alastair Graham, Marine Geophysicist, College of Marine Science, University of South Florida
Graham stated that to more precisely date the ridge-like characteristics, the researchers would like to sample the seabed sediments directly.
“But the ice closed in on us pretty quickly and we had to leave before we could do that on this expedition,” he said.
There are still many unanswered concerns, but one thing is certain, according to Graham: The Antarctic ice sheets are not at all what researchers had believed them to be.
“Just a small kick to Thwaites could lead to a big response,” he said.
According to the United Nations, about 40% of people live within 60 miles of the coast.
“This study is part of a cross-disciplinary collective effort to understand the Thwaites Glacier system better, and just because it’s out of sight, we cannot have Thwaites out of mind. This study is an important step forward in providing essential information to inform global planning efforts,” said Tom Frazer, dean of the USF College of Marine Science
The National Science Foundation and the UK Natural Environment Research Council funded the project through the International Thwaites Glacier Collaboration.
Journal Reference:
Graham, A. G. C., et al. (2022) Rapid retreat of Thwaites Glacier in the pre-satellite era. Nature Geoscience. doi.org/10.1038/s41561-022-01019-9.
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.
