Jason Paul, Steve Kokelj (2022). Mapping thermokarst land systems. Proceedings of the GWF Annual Open Science Meeting, May 16-18, 2022.

Permafrost has a profound influence over physical and biological processes shaping circumpolar environments. Models project widespread thawing of near-surface permafrost over the coming century, which will eradicate thin sporadic permafrost at its southern extent and shift the discontinuous zone northward. Anthropogenic climate change has intensified thermokarst processes such that ice-rich permafrost regions are being modified at increasingly rapid rates. Understanding how thaw-driven landscape change will manifest across a diverse range of biophysical environments, and anticipating the ecosystem, biogeochemical, carbon, and societal consequences remains a major knowledge gap in Arctic change science. The Thermokarst Collective (TKC) is a northern-driven mapping project initiated by the Northwest Territories Geological Survey to develop a comprehensive mapping inventory of remote-sensed thermokarst features across the entirety of the NWT. Hydrological, mass wasting, and periglacial thermokarst features are mapped within 7.5 x 7.5 km grid cells using Sentinel 10 m resolution imagery. In addition, a systematic aerial inventory and characterization of thaw-sensitive permafrost terrain was undertaken in summers of 2020 and 2021. During this time the project has assessed approximately 28,000 km of flight lines and compiled about 8,000 permafrost landform observations and thermokarst terrain attributes. These data are complemented with over 20,000 georeferenced oblique photographs that are being organized in a geospatial database. Here we present a some comparisons between TKC generated feature data with mapped or modelled features from published research examining particular regions of the NWT. The spatial data from this project show significant departures from modelled terrain sensitivity products highlighting the utility of broadscale empirical datasets. This mapping inventory characterizes over 25 variables describing thermokarst and periglacial landforms. We illustrate the depth of the datasets through exploring within and between regional variation in the suite of landforms that describe permafrost sensitivity. These analyses highlight that variation in geological and paleoenvironmental legacy and climate drivers combine to yield a diverse array of thermokarst and periglacial landform assemblages indicating the terrain consequences of permafrost thaw will vary in complex ways across the northern landscape. The novel and holistic approach to characterizing permafrost terrain taken in this project yields significant potential for exploring variation in terrain consequences of permafrost thaw, and provides a geological basis for re-framing how we think about what permafrost thaw will mean to the landscapes, ecosystems and communities of the north.

This research has implications for land cover changes, water availability, and water quality.

AOSM2022 First Author: Jason Paul Additional Authors: Steve Kokelj, Northwest Territories Geological Survey