What are ice wedges, and why are they important to climate change?

“I think ice wedges are what make permafrost interesting,” says Dr. Anna Liljedahl. 

Liljedahl works on Woodwell Climate’s Arctic team as an Associate Scientist. She aims to understand how climate change is affecting water storage and movement. Much of her recent work focuses on ice wedges and how they are reacting to warming Arctic summers. But just what are ice wedges anyway?

Ice wedges are one of the three main features of the Arctic’s land surface. Permafrost, ground that remains below 0˚C for at least two consecutive summers, lies under a thinner layer of thawing and refreezing soil, called the active layer. When permafrost cracks during cold winter days, snowmelt and runoff water seep into the empty space. These eventually freeze and create a wedge-shaped spear of ice that extends vertically down into the permafrost.

Ice wedges actively re-shape the tundra. When they freeze, they grow and expand outward, pushing against the bordering permafrost and active layer. With nowhere else to go, permafrost and soil push upwards, and ridges form on the surface of the tundra. The ridges interlock and form distinct shapes, referred to as ice-wedge polygons. 

The ridged borders of ice-wedge polygons form directly above expanding ice wedges below the surface, and are therefore more elevated. The lower internal portion of the polygon allows pools of water from runoff and snowmelt to form atop the active layer. These polygons are visible all the way from space. 

Thanks to satellite imagery, scientists like Liljedahl are able to monitor ice-wedge polygons remotely. Satellite images date back to the mid-20th century and can be used to observe changes in the landscape overtime. 

During unusually warm summers, the tops of ice wedges can melt, which removes underlying support of the ground surface, causing slumps along the borders of ice-wedge polygons. These leveling borders form channels that siphon the water from pools in the centers of neighboring polygons. The resulting runoff streams can drain small pools and even larger lakes that took thousands of years to form. 

With the progression of climate change, these drainage systems have become more common. Liljedahl refers to them in the title of her manuscript, just published in the July issue of Nature Water, “The Capillaries of the Arctic Tundra.”

The increase in creation of new “capillaries” in the Arctic is impacting not only the topographical landscape of the region, but also the livelihoods of all beings that find their home there. 

At first, the melt of these ice wedges can spark an uptick in the variation of vegetation due to moisture along the sides of the channel. This, however, is temporary. When the ice wedges stabilize again in the winter, this variation decreases once more. 

Aquatic mosses— one of the most productive vegetal forms in the Arctic, equivalent in productivity to Arctic shrubs— inhabit pools formed alongside the edges of ice-wedge polygons. They lose their homes when bodies of water drain away. Major vegetation changes can alter carbon storage, availability, and emissions across the tundra.

 Humans are also impacted. Homes become too dangerous to live in as the ground supporting vital infrastructure collapses. Roads connecting communities to important resources are destroyed by subsiding ground. 

Despite their widespread impact, ice wedges are often overlooked in Arctic climate models. Historically, their inclusion “costs too much computer time,” Liljedahl says, to factor in. Many climate models take a holistic approach to the Arctic landscape, as opposed to focusing on smaller details. 

To remedy this, Liljedahl suggests utilization of developing technology such as Artificial Intelligence (AI). Classifying the Arctic landscape by type, for example, into high-center polygons, low-center polygons, and capillary networks, would factor ice wedge change into climate models. As AI advances and becomes a more common research tool, it could help decrease the human computing time that Liljedahl identifies as a barrier. 

Arctic research is likely to change drastically in the coming years. With new technologies, and as we learn more about the Arctic landscape, research models will likely become more inclusive of the varied features within it, and much more accurate. 

“There are exciting years ahead,” Liljedahl says, “I think we’re going to see some cool stuff coming out [of tundra research] in the next five to ten years.”

The exhibit “In Flux: Perspectives on Arctic Change” sprawls across two floors of one of Cape Cod’s oldest summer-home mansions— Highfield Hall

When they first walk in, visitors see two of Woodwell Climate Board Member Georgia Nassikas’ encaustic paintings flanking a banner with the name of the exhibit. Woodwell Senior Geospatial Analyst Greg Fiske’s maps light up the entry hall. Sounds from Michaela Grill and Karl Lemiuex’s documentary film cascade down from the staircase to the second floor. Tall windows illuminate Gabrielle Russomagno’s small, detailed photographs of the Arctic’s durable vegetation and Aaron Dysart’s reflective sculpture, which invites us to tread with caution.

These six artists’ works have been on display in Highfield Hall since May 21st, and will remain as part of the “In Flux” exhibit until July 14th. On July 11th, some of the artists will participate in a panel discussion with their Woodwell scientist collaborators, Dr. Jennifer Watts and Dr. Sue Natali. 

Connecting to a new perspective

The exhibit’s goal is to connect a distant community to the reality of Arctic change. Many of us may never have the opportunity to visit the Arctic, or study it like Woodwell Climate researchers do. Art can help communicate the reality of an unfamiliar place. 

Woodwell Climate’s Arctic research informed every piece of art on display at Highfield Hall. Each artist has had the chance to travel to the Arctic alongside Woodwell researchers Dr. Jenny Watts and Dr. Sue Natali. According to Watts, traveling with an artist brought a new perspective to a landscape she had visited so many times before. 

“They are looking through the lens of the artist,” Watts says, “They’re kind of seeing it through this fresh look, and then we’re able to see it through their eyes.” 

Russomagno calls herself a “student of the Arctic.” Like some of the other artists, she had never been so far north before her 5-day trip with Watts to Alaska. She recalled the whirlwind experience of creating while acclimating to her new surroundings. 

“I was able to be making art while discovering,” Russomagno says, “I was looking at the same material [as Watts] and understanding it completely differently.”

The exhibit assumes visitors might come in with certain assumptions about the Arctic, but hopes they will soon throw their preconceived ideas out of Highfield Hall’s many windows. One of these false ideas, Watts says, is that the Arctic is a barren wasteland. 

“In the summer especially, it’s brimming with life, and we wanted to show that part of the story because it’s often overlooked,” she says. 

Bursts of life from the summer tundra— small shrubs, mosses, lichens, and grasses— are featured in Russomagno’s series of photographs in “The Quiet & the Mighty.” Nassikas’ encaustic paintings uniquely depict color, horizon, and change. Fiske’s maps teleport us from Highfield Hall to the tundra. The entire “In Flux” exhibit displays unexpected dimension. 

Why combine art and science?

The experience of the art at Highfield places the viewer in the atmosphere of the Arctic tundra. A quiet place with unexpected vibrancy, the uptick in frequency of deafening crashes as ice melts, breaks, and shifts. These elements would be much harder to glean from traditional methods of communication in the science world. A graph, for example, would likely not evoke such a strong emotional response. 

“I think Woodwell and other science organizations struggle with conveying their data, and hard facts, and things they’re discovering to a general audience,” Nassikas says, “Art is another way to change the world for the better.” 

Dysart echoed this message: “If research does not connect with people and culture, nothing’s going to change. Art can make that connection. Art has strength that words don’t.” 

Our shared home

Part of the power of this exhibit is its setting. We have the opportunity to experience the Arctic’s dynamic changes outside of its natural barriers, and Highfield Hall is the tether. 

Dysart says it is “A call back to [our] normal life as opposed to the gallery aesthetic.”

Highfield is a home. It may not feel familiar to everyone, with its extravagant furnishings, stained glass windows, chandeliers, and many rooms, but it was built by humans, for humans. The house has withstood the test of time, though it has changed greatly since its construction in 1878. The Arctic, too is a home for many people, animals, and plants— one that is threatened by climate change. The exhibit at Highfield Hall brings the changing Arctic home to our own changing landscape.