The Permafrost Discovery Gateway (PDG) invites you to join our monthly webinar series on Thursday July 3, 2025 at 9:00 am AKT. The webinar series addresses using big geospatial data and remote sensing for community planning applications across permafrost regions.
July 3, 2025
Pan-Arctic Volumetric Quantifications of Areas Undergoing Retrogressive Thaw Slumping
Speaker: Chunli Dai, University of Florida
Abstract: Retrogressive thaw slumping (RTS) is a mass-wasting process that occur in ice-rich permafrost areas due to the melting of ground ice. Owing to the increased availability of high-resolution (2 m) time-dependent digital elevation models (DEMs) from ArcticDEM, the first volumetric quantification of medium to large RTSs (>=10,000 m2) is carried out for the Northern Hemisphere. Using DEM time-series analysis and deep learning, we retrieve a total of 2,747 active RTS across the Arctic, with a median volume loss of 62,484 m3 and a total volume loss of (317.0 ±0.3) ×106 m3 during the past decade. The soil organic carbon calculations from this pan-Arctic active RTS inventory indicate a total of 1.95×10-3 Pg carbon per year (where 1 petagram =1 gigatonnes) between 2012 and 2022, three orders of magnitude less than initial abrupt thaw model estimates. The RTS inventory also provided new estimates for the area-volume scaling relationship with most regions clustered around a scaling exponent of 1.24 to 1.33. Climatic drivers of RTS activity exhibited latitudinal and regional variations, specifically, the number of precipitation-driven RTSs decreased linearly as latitudes increased whereas temperature-driven RTSs increased sharply. This study presents the first high-quality inventory of RTS and volume estimates on a pan-Arctic scale, which is made possible by collaboration between remote sensing scientists and disciplinary experts.