Landscape evolution and adapting to change in ice-rich permafrost systems

Overview: Ice-rich permafrost systems (IRPSs) are geoecological systems associated with ground that has been frozen for at least two years and contains a high amount of ground ice that exceeds the pore space in the soils. If thawed, this "excess ice" melts and the soils subside irregularly creating thermokarst features, including thermokarst pits, ponds, thaw slumps, and mounds.  Studies across the Arctic have shown recent increases in the occurrence of thermokarst features resulting from a warmer climate and/or altered hydrology, snow cover, or vegetation changes. This project has two major components related to thermokarst: Landscape Evolution and Adaptations.

The Landscape Evolution Component focused on transformations to hydrological features, landforms, and vegetation caused by thermokarst in roadside areas and natural landscpes in Deadhorse Ice-Rich Permafrost Observatory (DIRPO) in the Prudhoe Bay Oilfield (PB0), Alaska (Figure 1). Past phases of this project found that the most extensive changes occur near road and other infrastructure due to warming soils related to flooding, altered snow regimes, road dust, and other infrastructure-related disturbnces. The more recent phase focused in natural areas distant from roads.  Landcover mapping using high-resolution satellite images and Lidar-derived digital elevation data (Figure 2) and integrated terrain-change mapping (Figure 3) documented extensive changes that occurred between 1980 and 2020 on four key surficial geology units at the DIRPO. The most extensive changes occured on residual surfaces of alluival plain deposits. The area of thermokarst ponds on the residual surface at the DIRPO site increased by approximately 13%, compared to 4% on an ice-rich thaw-lake deposit, and 0% on a recent ice-poor thaw-lake deposit. There was also a corresponding 78% reduction in the area covered by low-center ice-wedge polygons and a 74% increase in high-center polygons on the residual surface. The changes are directly related to expansion of the width of polygon troughs and loss of ice-wedge-polygon rims. Ongoing studies are focused on subsurface geophysics (Figure 4) and ice cores (Figure 5) in the different surficial-geology units. They reveal colder ground temperatures, and more excess ice in the the residual surfaces.  The transformations have had major consequences to the ecosystems on the calcareous alluvial gravel floodplain deposits that underlie the Prudhoe Bay Oilfield, the Dalton Highway and floodplains of rivers that flow out of the limestone mountains of the central and eastern Brooks Range. These systems are characterized by unique gravel-cored pingos, broad-based pingos, marl-bottomed lakes, Mollisol (prairie-like) soils, nonacidic plant communities, and rich wildlife assemblages associated with the braided rivers and calcareous loess blowing off the rivers. A synthesis of the landscape evolution component is currently in progress and will aid in developing ground-ice sensitivity maps, land-use planning, and engineering oilfields and road networks to minimize impact to these valuable resources.

The Adaptations Component focused on the impacts of changing ground-ice conditions in the village of Point Lay, Alaska. Researchers and community members in the Native Village of Point Lay (Kali), Alaska, worked together to better understand how climate change and infrastructure development are driving thaw of the region’s ice-rich permafrost. Over the life of the award, this collaboration supported deep place-based research and co-produced knowledge with direct relevance to Arctic engineering, community planning, and environmental justice.The work began with extensive community engagement and built on long-term relationships and trust. A regional advisory group that included representatives from Point Lay met quarterly to guide project direction and ensure local relevance. These meetings helped frame shared research priorities around thaw-related impacts to homes, roads, and essential utilities.Field investigations from 2022 to 2024 combined borehole drilling (62 total), cryostratigraphic logging, and laboratory analyses of ice content, moisture, and salinity. The findings confirmed that Point Lay is underlain by permafrost with extremely high ground-ice content, especially deep ice wedges that are vulnerable to both warming and surface disturbance. These results, paired with air photo time series and drone mapping, showed that infrastructure development has dramatically accelerated thermokarst processes in the community. Thaw-related ground subsidence has undermined home pilings, disconnected fire hydrants, and compromised water and sewer infrastructure. Photos of each home and orthographic mapping provide a snapshot of Pt. Lay allowing future researchers to quantify the rates of change within and near the village.Interviews with residents provided powerful firsthand accounts of how permafrost thaw is affecting daily life, highlighting damage to homes, growing reliance on alternative water access and access to subsistence lands. These narratives were central to developing a set of engineering recommendations—including pile redesign, snow management, and better drainage strategies tailored for communities on ice-rich ground. The project also resulted in public data releases, including a comprehensive geospatial dataset, borehole database, and a community-facing report on permafrost conditions in Point Lay. A scientific paper published in Environmental Research: Ecology showcases the Point Lay case study as a warning signal for Arctic permafrost communities across the circumpolar North (Figure 6).