In northernmost Alaska, a battle is on to limit the damages of permafrost thaw

Nearly 20 feet below the ground of a field of open tundra in the nation’s northernmost community, an icy world gives a picture of the ancient past and the future of this part of the Arctic.

Embedded in the walls of a tunnel is frozen peat, its features perfectly preserved from 10,000 years ago. 

“It’s quite fresh, and it keeps the shape of the moss,” said Go Iwahana, a University of Alaska Fairbanks scientist who descended down a metal ladder to reach a low, 10-meter (32-foot) long tunnel built into the permafrost in the 1960s.

Sloshing below the floor are mobile pools of super-salty and bacteria-packed brine, the remnants of an ancient lagoon that dates back at least 40,000 years and is completely cut off from the Arctic Ocean.

Within the soil, though, the modern world is making its mark. Iwahana, crawling around along the low tunnel, sent probes 1.5 to 2 meters down boreholes to see how the modern world has made its mark. “Three,” he called out after reading a thermometer.

The soil here has warmed over the past decade from minus-6 degrees Celsius to minus-3 , or from 21.6 degrees to 26.6 degrees Fahrenheit, said Iwahana, who works at UAF’s International Arctic Research Center.

“That’s a lot,” he said.

Findings at the tunnel are consistent with those elsewhere on the North Slope. As air temperatures rise, the soils as deep as 20 meters below the surface are warming at a rate of up to 4 degrees Celsius per decade, according to long-term measurements by UAF scientists.

For Utqiagvik, the North Slope’s biggest community and home to nearly half of the North Slope Borough’s residents, the unrelenting warming means trouble.

The most obvious is seen at the places where ice-rich permafrost is closest to the surface: the coastline at Utqiagvik’s downtown core, where a bluff has cleaved dangerously close to the edge of houses. Beneath one abandoned house is a gaping hole where the bluff has completely eroded away. Another house, owned by Doreen Fogg-Leavitt’s mother-in-law, is teetering on the edge.

“I remember 20 years ago, when her backyard to the edge was a good 30 feet, 40 feet. Now it’s about three,” said Fogg-Leavitt, natural resources manager for the Inupiat Community of the Arctic Slope, the local tribal government.

The North Slope has some of the fastest erosion measured in the nation, according to the U.S. Geological Survey, and rates have accelerated. The coastline is losing as much as 9.5 meters a month, according to findings by Williams College researchers presented in mid-December at the annual conference of the American Geophysical Union.

The long-term warming of frozen soil that Iwahana and his UAF colleagues are measuring in the tunnel is just one of the factors that work in combination to erode the coastline.

Another is sea ice loss. More open water – persisting this year into late November – means more opportunities throughout the year for waves to hit the beach and make contact with permafrost bluffs. That causes “niche-erosion block collapse,” said Tom Ravens, a University of Alaska Anchorage civil engineering professor.

There are more subtle factors, too, which Ravens listed at a permafrost workshop held in Anchorage in November. A change in precipitation patterns from snow to rain sends heat from the surface into the soil. The ocean water, aside from bringing soils in contact with heat, also contains salt, another thaw factor. Long-term thawing is causing vast stretches of land to sink, pulling down the coastline along with the rest of the landscape. Measured sinking across the North Slope from 2017 to 2022 averaged 3 centimeters to 5.8 centimeters, depending on location, according to UAF research to be presented at this month’s AGU annual meeting.

Sophisticated revetment to replace sand-filled bags and sand piles

At Utqiagvik, erosion is especially worrisome because of the large size of the community – about 4,500 people – and the large concentration of important infrastructure, including buildings, roads, utilities and, right next to the beach, a landfill.

The North Slope Borough in recent years has piled up masses of sand-filled Supersacks, delivered by barge each summer, to keep the sea’s water away from the most vulnerable resources. Beyond the walls of Supersacks, the borough uses heavy equipment to pile up beach sand into a makeshift barrier.

A more durable fix is on the way.

The U.S. Army Corps of Engineers is putting the final touches on the design for five miles of what’s known as a “revetment” to protect the shoreline. It is a massive project that has been several years in the planning and is expected to take at least six years to complete, said Bruce Sexauer, chief of civil works project management for the Corps of Engineers’ Alaska district.

In the past, Utiqagvik has been able to do a little mix of “managed retreat,” moving some buildings and property away from the disappearing shoreline. But the region is fairly flat, and those options are largely exhausted.

“Now they are at a place where the important infrastructure is right up next to the edge. Their water supply and sewage lagoon are right up against the edge,” Sexauer said. The revetment project is seen as the most practical long-term solution, and Utqiagvik’s position as a service and business hub gives all North Slope communities a stake in it.

“If Utqiagvik suddenly had a catastrophic issue, that would have an effect on the other communities in the area,” Sexauer said.

The full cost of the revetment project is yet to be determined. The 2022 Disaster Relief Supplemental Appropriations Act included a provision that puts $364.3 million into the project.

The Corps expects to formally seek bids this coming summer for the first phase of the project, the 0.75-mile section right at the central bluff, Sexauer said. A request for bids for the rest of the project is expected about a year later. The full project also incorporated a rebuild of Stevenson Street to raise the elevation of the oft-flooded roadway leading north of town toward Point Barrow.

Site-preparation work for the erosion-control project is expected to start in 2024, Sexauer said. 

The revetment design plan is for multiple layers of different material with varying porosity, from industrial fabric to large boulders, to preserve the ground’s cold temperatures, Sexauer said. That type of multilayer technology has proved to be successful, so far, for a much-smaller revetment at the erosion-threatened village of Shishmaref farther south in the Bering Strait region, according to Corps of Engineers’ reports.

It is important that the revetment be more than a simple rock wall, said one expert.

“Even if you build a rock revetment very strong, the permafrost below can degrade,” said Ming Xiao, a Pennsylvania State University civil engineering professor. “You can’t just build on the existing permafrost.”

Xiao is leading a project, with collaborators from UAF and Virginia Tech University, that uses a buried fiber-optic cable to measure the minute movements within the soil of Utqiagvik’s warming permafrost. The hope is that the underground vibrations, when correlated with temperature measurements, can forecast conditions in decades to come. “Then we can predict in the future, say 50 years, what the ground temperature is going to be,” he said. And that, in turn, will give information about whether the ground is too weak to support any structures atop it, he said.

The Supersacks are certainly not up to the erosion-control task, Xiao said. For one thing, he said, they are made of material that degrades when exposed to the sun’s ultraviolet light, something that is unrelenting in summer. For another, the sacks can be punctured in rough weather, “and the wave is going to pick up the Supersasck and put it into the ocean,” he said.

Below-ground threats to pipelines and cellars

Beyond the eroding shoreline, a less-visible thaw problem lies beneath the surface: threats to underground pipes for water and utilities.

About a third of Utqiagvik’s water, wastewater and electrical lines run through a protected, temperature-controlled tunnel called the “Utilidor.” Built in the oil-money heyday of the 1980s, the Utilidor was too expensive to extend beyond its initial 3 miles. That leaves most of the rest of the system with underground piping, and thaw risks lurk even 12 feet below the ground’s surface.

That danger materialized in a different North Slope community in the spring of 2021. In Point Lay, 180 miles southwest of Utqiagvik, a sudden thaw collapse in the permafrost severed a main water line, temporarily cutting off flow of water to the village clinic and to several houses. It was a particularly ill-timed event, as it came during the COVID-19 pandemic, when clean water became a critical need.

Protected as it is, the Utilidor is not impenetrable. Storms in 2015 and 2017 came close to sending water flooding into it, according to the Corps of Engineers. With waves breaking up the seasonally maintained beach berms, seawater also came close to contaminating the freshwater lagoon, the Corps reported. In October, Utqiagvik was slammed by a storm that, though not as serious as the 2015 and 2017 events, pushed saltwater from the sea again over barriers to flood Stevenson Street and enter the lower lagoon; one more breach and seawater would have hit the city’s upper-lagoon drinking water supply.

Permafrost thaw, in combination with storm flooding, is encroaching on some cultural practices, too.

Many of the community’s traditional Inupiat permafrost cellars, known as sigluaqs, have been damaged by flooding or other incursions.

That happened in 2015 to the sigluaq maintained by Fogg-Leavitt’s family. While there was no pooled water in it, the temperatures rose high enough to thaw the meat. It remained edible, she said, but the taste was compromised; the blood ran out during the thaw, meaning it was impossible to create the traditional fermented product.

The thaw threats have prompted some changes in practices, she said. “Some younger crews are using walk-in freezers exclusively,” she said. But others are passionate about keeping their sigluaqs intact and functional. To that end, ICAS is experimenting this winter with technology: installation of thermosyphons, devices that pull heat out of the ground passively. Only a few cellars are to be included in the first phase of the project, but it could be expanded in the future, she said.

“This is what we’re going to do to sustain our culture,” Fogg-Leavitt said. “We’ll see if it works.”

Gravesites and archaeological resources at risk

Thaw effects extend even to the dead.

That is seen at the modern cemetery, where grave markers have tilted as the ground below warmed. It is also seen at the central bluff in town, where remnants of historic homes made of sod and driftwood are crumbling away, and at more remote sites, to more remote coastal area, where sometimes-ancient artifacts and even gravesites are being lost.

Rescuing those sites has been the mission of archaeologist Anne Jensen. Now with Bryn Mawr College, Jensen lived for decades in Utqiagvik and previously worked for the Ukpeaġvik Iñupiat Corp.’s science department.

When the 800-year-old remains of a young girl were uncovered by erosion in 1994, Jensen was on the case; the girl was determined to have been a victim of starvation and numerous chronic diseases. She was named Anaiyaaq, meaning “young girl,” and her body was reburied.

When accelerating erosion was exposing gravesites at Nuvuk, an ancient settlement at Point Barrow, Jensen was also at work to rescue remains; the sites were from a cemetery area with use stretching back about 1,000 years. She has done other work at a well-known archaeological site about 18 miles down the Chukchi Sea coast called Walakpa, which was thought to be stable until about a decade ago, when a fall storm began carving off the once-frozen bluff.

The vulnerable archaeological sites are not just about culture, Jensen said. “Sites are not just culture. They are a frozen tissue archive. Everything in it is preserved.” That includes ancient DNA in both tissues and sediments, stable isotopes and other pieces of information that can be used to reconstruct past conditions, she said.

The places where Jensen has worked represent only a small fraction of the archaeological and cultural sites packed along the coastlines at Utqiagvik and elsewhere on the North Slope. Several have already been lost, such as the 100-year-old Esook Trading Post that was swallowed by the Beaufort Sea in the early 2000s. Many more are likely to wash away before anyone knows what they held, Jensen said.

“There’s not enough money on the planet. It’s either excavate them or write them off,” she said.

GET THE MORNING HEADLINES DELIVERED TO YOUR INBOX

SUBSCRIBE