Collaborative research: thaw below zero - how warming saline permafrost controls key arctic landscape processes

This $1,039,772 federal Project Grant award from the National Science Foundation's Polar Programs (CFDA 47.078) supports research by the University of Alaska Fairbanks (UAF) to study the impacts of warming saline permafrost in the Arctic. The key research objectives are to: 1) Analyze the spatial distribution and properties of saline permafrost, 2) Assess how ice wedge formation and thaw have influenced near-surface saline permafrost, and 3) Determine the response of warming saline permafrost under shallow thermokarst lakes. The research will combine field studies, laboratory soil testing, geophysical measurements, sensor networks, and remote sensing to establish quantitative relationships between salinity, permafrost characteristics, and Arctic landscape change processes. This project will advance fundamental permafrost science, contribute to understanding permafrost evolution in a warming Arctic, and provide a basis for predicting climate change impacts on permafrost terrain. UAF will collaborate with Iḷisaġvik College and the University of Wyoming on this multi-year project starting in September 2024.

Abstract

Permafrost, or perennially frozen ground, is defined as any earth material that remains at or below 0?C for two or more consecutive years. This fundamental definition implies that soil thaws at 0?C or that ground-ICE melts at 0?C. However, if salts or salty water are present (saline permafrost), the earth material can thaw or remain unfrozen at temperatures below 0?C. Saline permafrost is widespread in the terrestrial arctic environment, occurring across ~35% of the continuous permafrost region. The impacts of warming saline permafrost on natural processes in the arctic and its reaction to climate change have received little research attention to date. The thaw below zero project is an important next step in studies of permafrost responses to a warming arctic because saline permafrost is degrading more quickly than other types of permafrost. Knowledge of saline permafrost dynamics in a warming world can better inform earth system models that predict global climate change. Information exchanges with local and regional land management agencies on the effects of warming saline permafrost on natural and human-modified arctic environments will assist in community resilience and future planning efforts. The project will broaden participation through the inclusion of undergraduate students from I?ISA?VIK college in utqia?VIK, a graduate student at the university of wyoming, and an early career female researcher at the university of alaska fairbanks. This project addresses policy elements identified in the FY2022-26 interagency arctic research policy committee arctic research plan related to permafrost and its role in arctic system interactions as well as risk management and hazard mitigation. Warming of permafrost across the northern hemisphere has been well documented. Since the 1980S, the mean annual temperature of cold, continuous permafrost in northern alaska has increased by 2-3?C. Nevertheless, this region is typically considered to be relatively safe from permafrost degradation since ground temperatures remain well below 0?C. However, considering the high ground-ICE content in saline soils of the upper permafrost in northern alaska, we may expect extensive thaw settlement and an increase in landscape change rates because of permafrost warming and thawing at temperatures below 0?C. The thaw below zero project will advance fundamentals of permafrost science, contribute to a better understanding of permafrost evolution in a warming arctic, and provide a basis for predicting climate change impacts on permafrost terrain by clarifying the effect of warming saline permafrost on key natural landscape processes in the arctic. The project will combine permafrost field studies, laboratory soil testing, geophysical field and laboratory measurements, environmental sensor networks, and remote sensing to (1) study the spatial distribution and properties of saline permafrost; (2) assess how ICE wedge formation and subsequent thaw in the holocene have influenced the depth to and distribution of near-surface saline permafrost; and (3) determine the response of warming saline permafrost below shallow thermokarst lakes. The primary research product of these combined objectives will be the establishment of quantitative relationships between salinity, permafrost characteristics, and arctic landscape change processes and their rates. Project results will fill fundamental knowledge gaps in the evolution of arctic permafrost landscapes and provide necessary information for characterizing and understanding future permafrost landscape behavior. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the foundation's intellectual merit and broader impacts review criteria.- subawards are planned for this award.