Aerial image of interspersed a permafrost peatland in Innoko National Wildlife Refuge in Alaska interspersed with smaller areas of thermokarst wetlands. Credit: Miriam Jones, U.S. Geological Survey
Abrupt thawing of permafrost will double previous estimates of potential carbon emissions from permafrost thaw in the Arctic, and is already rapidly changing the landscape and ecology of the circumpolar north, a new CU Boulder-led study finds.
Permafrost, a perpetually frozen layer under the seasonally thawed surface layer of the ground, affects 18 million square kilometers at high latitudes or one quarter of all the exposed land in the Northern Hemisphere. Current estimates predict permafrost contains an estimated 1,500 petagrams of carbon, which is equivalent to 1.5 trillion metric tons of carbon.
The new study distinguishes between gradual permafrost thaw, which affects permafrost and its carbon stores slowly, versus more abrupt types of permafrost thaw. Some 20% of the Arctic region has conditions conducive to abrupt thaw due to its ice-rich permafrost layer. Permafrost that abruptly thaws is a large emitter of carbon, including the release of carbon dioxide as well as methane, which is more potent as a greenhouse gas than carbon dioxide. That means that even though at any given time less than 5% of the Arctic permafrost region is likely to be experiencing abrupt thaw, their emissions will equal those of areas experiencing gradual thaw.
This abrupt thawing is “fast and dramatic, affecting landscapes in unprecedented ways,” said Merritt Turetsky, director of the Institute of Arctic and Alpine Research (INSTAAR) at CU Boulder and lead author of the study published today in Nature Geoscience. “Forests can become lakes in the course of a month, landslides occur with no warning, and invisible methane seep holes can swallow snowmobiles whole.”
Abrupt permafrost thaw can occur in a variety of ways, but it always represents a dramatic abrupt ecological shift, Turetsky added.
“Systems that you could walk on with regular hiking boots and that were dry enough to support tree growth when frozen can thaw, and now all of a sudden these ecosystems turn into a soupy mess,” Turetsky said.
Why thawing permafrost matters
Permafrost contains rocks, soil, sand, and in some cases, pockets of pure ground ice. It stores on average twice as much carbon as is in the atmosphere because it stores the remains of life that once flourished in the Arctic, including dead plants, animal and microbes. This matter, which never fully decomposed, has been locked away in Earth’s refrigerator for thousands of years.
Trees struggle to remain upright in a lake formed by abrupt permafrost thaw. Credit: David Olefeldt
As the climate warms, permafrost cannot remain frozen. Across 80 percent of the circumpolar Arctic’s north, a warming climate is likely to trigger gradual permafrost thaw that manifests over decades to centuries.
But in the remaining parts of the Arctic, where ground ice content is high, abrupt thaw can happen in a matter of months—leading to extreme consequences on the landscape and the atmosphere, especially where there is ice-rich permafrost. This fast process is called “thermokarst” because a thermal change causes subsidence. This leads to a karst landscape, known for its erosion and sinkholes.
Turetsky said this is the first paper to pull together the wide body of literature on past and current abrupt thaw across different types of landscapes.
The authors then used this information along with a numerical model to project future abrupt thaw carbon losses. They found that thermokarst always involves flooding, inundation, or landslides. Intense rainfall events and the open, black landscapes that result from wildfires can speed up this dramatic process.
The researchers compared abrupt permafrost thaw carbon release to that of gradual permafrost thaw, trying to quantify a “known unknown.” There are general estimates of gradual thaw contributing to carbon emissions, but they had no idea how much of that would be caused by thermokarst.
They also wanted to find out how important this information would be to include in global climate models. At present, there are no climate models that incorporate thermokarst, and only a handful that consider permafrost thaw at all. While large-scale models over the past decade have tried to better account for feedback loops in the Arctic, the Intergovernmental Panel on Climate Change (IPCC)’s most recent report only includes estimates of gradual permafrost thaw as an unresolved Earth system feedback.
“The impacts from abrupt thaw are not represented in any existing global model and our findings indicate that this could amplify the permafrost climate-carbon feedback by up to a factor of two, thereby exacerbating the problem of permissible emissions to stay below specific climate change targets,” said David Lawrence, of the National Center for Atmospheric Research (NCAR) and a coauthor of the study.
The findings bring new urgency to including permafrost in all types of climate models, along with implementing strong climate policy and mitigation, Turetsky added.
“We can definitely stave off the worst consequences of climate change if we act in the next decade,” said Turetsky. “We have clear evidence that policy is going to help the north and thus it’s going to help dictate our future climate.”
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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.
