UBC-Led Study Reveals Thawing Permafrost Slumps Reshaping Herschel Island-Qikiqtaruk

On the remote shores of Herschel Island-Qikiqtaruk in Yukon's northern Beaufort Sea, the Arctic landscape is undergoing a profound transformation. Massive retrogressive thaw slumps—giant landslides triggered by melting permafrost—are reshaping the terrain, exposing ancient ice and releasing vast amounts of stored carbon. This dynamic site, a Yukon Territorial Park managed in partnership with the Inuvialuit, serves as a critical natural laboratory for Canadian researchers studying the frontlines of climate change.

Recent observations from University of British Columbia professor Isla Myers-Smith and her Team Shrub highlight how these slumps grow year after year, biting deeper into the tundra. Drone surveys since 2015 and on-the-ground monitoring with local park rangers reveal cliffs forming at slump heads that retreat steadily, disturbing soil layers frozen for millennia. The island, just five kilometers off the Yukon coast, exemplifies the accelerating permafrost degradation across the Canadian Arctic.

Breakthrough Findings from the Latest Nature Climate Change Study

A landmark paper published in March 2026 in Nature Climate Change, titled "Vegetation recovery following retrogressive thaw slumps across northern tundra regions," provides the most comprehensive analysis to date. Led by researchers from the University of Illinois Urbana-Champaign and the Chinese University of Hong Kong, the study analyzed satellite data from PlanetScope, Landsat, and high-resolution imagery across 12 Arctic sites, including Herschel Island-Qikiqtaruk as a key validation location.

Using normalized difference vegetation index (NDVI) as a proxy for greenness and productivity, the team identified recovery phases: disturbance, regrowth, and stabilization. On Herschel Island, vegetation reached pre-slump NDVI levels in about 25 years, aligning with a power-law model predicting recovery time (τ) based on gross primary productivity (GPP): τ = 1.35 × (GPP)^-1.68. With a site GPP of 0.18 kgC m⁻² yr⁻¹, the model estimated 24.1 ± 3.0 years—spot-on with field observations of tussock sedge, dwarf shrub, and moss tundra recolonizing disturbed areas.

Low-Arctic sites like the Mackenzie Delta recover in 5-10 years, often greening beyond original states due to shrub encroachment, while high-Arctic areas lag at 30-100+ years. This variability underscores regional differences in climate, soil nutrients, and moisture, with Herschel Island bridging low- and high-Arctic traits.

UBC's Team Shrub: Leading On-Site Permafrost Monitoring

At the University of British Columbia, Isla Myers-Smith's Team Shrub is at the vanguard of this research. Recently transitioned from the University of Edinburgh, Myers-Smith directs long-term ecological monitoring on Qikiqtaruk, collaborating with Yukon Parks rangers like retired Inuvialuit elder Richard Gordon. Their work integrates drone photogrammetry, repeat photography from 1989, and ground measurements of active layer depth, phenology, and vegetation plots.

"You get this sort of bite out of the ground that grows successively bigger and bigger each year as more of that ice is exposed," Myers-Smith explained in recent interviews. The team's Tundra THAW Project maps slump progression, distinguishing active layer detachments (ALDs)—smaller slides—from full RTS, and probes drivers like extreme heat thawing deep permafrost.

This hands-on approach complements satellite data, providing validation for global models. UBC students and postdocs contribute to fieldwork, gaining invaluable Arctic experience amid Canada's push for northern research capacity.

Understanding Retrogressive Thaw Slumps: Step-by-Step Formation

Retrogressive thaw slumps (RTS) begin when surface disturbances—wildfires, erosion, or heatwaves—thaw the active layer, the topsoil that defrosts annually. Beneath lies ice-rich permafrost, comprising 20-50% massive ice in syngenetic sediments on Qikiqtaruk.

1. Initiation: Thaw exposes ice wedges or lenses, melting creates a mudflow lobe.
2. Headwall Retreat: A steep ice cliff (headwall) forms, retreating upslope at 10-25 meters per year as ablation exposes more ice.
3. Debris Fan: Slumped material forms a tongue-shaped deposit, rich in organic carbon and sediments.
4. Stabilization or Reactivation: Vegetation stabilizes or polycyclic activity restarts after decades.

On Herschel Island, over 160 RTS dot the coast, with Slump D among the Arctic's largest. Yukon University researchers, via the Permafrost and Geoscience Research Chair, have drilled cores revealing Holocene ice ages (3,470-9,220 years), informing slump vulnerability models.

Vegetation Succession: From Barren to Shrub-Dominated Tundra

Post-slump, bare mineral soil hosts pioneer species: mosses, graminoids (sedges, grasses), and forbs. NDVI rises rapidly in moist, nutrient-enriched debris, but full compositional recovery lags.

Herschel Island data shows tussock tundra returning in 25 years, but with shifts: low-Arctic sites see erect shrubs (willows, alders) dominate after 10-20 years, boosting biomass and GPP. High-resolution imagery classifies plant functional types (PFTs), revealing ternary plots of bare ground, low-stature, and shrubs.

Canadian-led chronosequence studies validate this: UBC's shrubification monitoring documents 20th-century canopy willow expansion, accelerated by slumps creating shrub-friendly microsites.

Photo by Dawn Lio on Unsplash

The 2023 Heatwave: Catalyst for Unprecedented Landslides

August 2023's three-week heatwave—5°C above norms—triggered over 700 ALDs on Qikiqtaruk, many evolving into RTS. Rangers heard "moaning" ground as tundra slid into valleys and sea, increasing coastal erosion rates.

UBC analysis links this to record active layer depths, priming ice exposure. Sediment plumes altered nearshore waters, impacting fish runs like Dolly Varden.

Implications for Inuvialuit Communities and Subsistence

Inuvialuit elders like Gordon emphasize land's power: "It’s the last frontier where we have permafrost and … we’re losing it each and every year." Slumps eliminate caribou calving grounds—no sightings recently—forcing shifts to whitefish harvesting amid turbid waters delaying fish migrations.

Higher education bridges gaps: YukonU trains Indigenous youth in geoscience, fostering co-management with parks. UBC's community-engaged research informs adaptation plans.

For deeper insights, explore the full Nature Climate Change study.

Carbon Feedbacks: Amplifying Arctic Warming

RTS mobilize 10,000-100,000 tons of sediment annually per slump, releasing organic carbon via mineralization. While low-Arctic regrowth sequesters carbon faster, high-Arctic lags create net sources.

Quantified via GPP models, Herschel's 25-year recovery balances disturbance losses, but chronic reactivation risks feedback loops. Canadian satellite networks, bolstered by UBC data, track circumpolar RTS expansion.

Canadian Universities Driving Permafrost Science

Beyond UBC, Yukon University hosts the Permafrost Research Chair, joining Nunataryuk (EU-Canada) on coastal thaw. Past McGill/Laval collaborations mapped 50-year RTS evolution.

These efforts position Canada as a leader, training grad students in remote sensing, geocryology, and ecology amid $multi-million NSERC grants.

Future Outlook: Adaptation and Research Frontiers

Predictions: RTS frequency triples by 2100 under warming. Universities pioneer resilient infrastructure, Indigenous knowledge integration, and VR tools (Qikiqtaruk VR project).

Team Shrub's June return promises new data, emphasizing higher ed's role in actionable science.

Photo by Artem Beliaikin on Unsplash

Higher Education's Vital Role in Arctic Resilience

From UBC fieldwork to YukonU policy advising, Canadian postsecondary institutions equip the next generation for permafrost challenges. Programs in cryospheric sciences foster interdisciplinary solutions, blending ecology, engineering, and Indigenous perspectives for sustainable northern futures.