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The ground thermal regime has a profound impact on geomorphological processes and has been suggested to be particularly important for weathering processes in periglacial environments. Several frost-related damage indices have hitherto been developed to link climate and frost weathering potential in bedrock, although only for individual points or grid cells. Here, we model ground temperature and frost weathering potential in steep rock walls in the Jotunheimen Mountains, southern Norway, along a two-dimensional profile line for the Younger Dryas Stadial-Preboreal transition (c. 11.5 ka), the Holocene Thermal Maximum (c. 7.5 ka), the Little Ice Age (1750), and the 2010s. We use an established heat flow model and frost-cracking index based on the ice segregation theory. A central innovation of our model treatment is the implementation of ensemble simulations using distributions of automatically mapped crack radii in a rock wall, whereas previous frost damage models considered only a single characteristic crack radius. Our results allowed for the identification of sites with enhanced frost weathering. Such sites are typically found between rock walls and retreating glaciers, as well as in areas where snow depth changes abruptly, resulting in large thermal gradients. Hence, frost weathering may be highly active during glacier retreat, enhancing the damage to rock walls during deglaciation by adding to the damage from stress release. The coldest climates of the Younger Dryas Stadial-Preboreal transition and the Little Ice Age were generally most favorable for frost cracking. Such timing compares well with the knowledge about the timing of rockfall accumulations in Norway. 

Abstract The presence of ground ice in Arctic soils exerts a major effect on permafrost hydrology and ecology, and factors prominently into geomorphic landform development. As most ground ice has accumulated in near-surface permafrost, it is sensitive to variations in atmospheric conditions. Typical and regionally widespread permafrost landforms such as pingos, ice-wedge polygons, and rock glaciers are closely tied to ground ice. However, under ongoing climate change, suitable environmental spaces for preserving landforms associated with ice-rich permafrost may be rapidly disappearing. We deploy a statistical ensemble approach to model, for the first time, the current and potential future environmental conditions of three typical permafrost landforms, pingos, ice-wedge polygons and rock glaciers across the Northern Hemisphere. We show that by midcentury, the landforms are projected to lose more than one-fifth of their suitable environments under a moderate climate scenario (RCP4.5) and on average around one-third under a very high baseline emission scenario (RCP8.5), even when projected new suitable areas for occurrence are considered. By 2061–2080, on average more than 50% of the recent suitable conditions can be lost (RCP8.5). In the case of pingos and ice-wedge polygons, geographical changes are mainly attributed to alterations in thawing-season precipitation and air temperatures. Rock glaciers show air temperature-induced regional changes in suitable conditions strongly constrained by topography and soil properties. The predicted losses could have important implications for Arctic hydrology, geo- and biodiversity, and to the global climate system through changes in biogeochemical cycles governed by the geomorphology of permafrost landscapes. Moreover, our projections provide insights into the circumpolar distribution of various ground ice types and help inventory permafrost landforms in unmapped regions.