High potential for loss of permafrost landforms in a changing climate

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.

Rock glaciers and related cold rocky landforms: Overlooked climate refugia for mountain biodiversity

“…Today, we see continuing evidence of this pattern with elevationally or latitudinally disjunct populations of some species in CRL-linked habitats (Fickert et al, 2007;Růžička & Zacharda, 1994). Thus, evidence from both the past and present strengthens the prediction that CRLs will sustain long-lasting cold refugia under contemporary climate change (Caccianiga et al, 2011;Gobbi et al, 2014;Millar et al, 2015;; but see Karjalainen et al, 2020).…”

Environmental Controls of InSAR‐Based Periglacial Ground Dynamics in a Sub‐Arctic Landscape

“…Several studies have shown the potential of statistical modeling to estimate permafrost distribution (Aalto, Karjalainen, et al., 2018; Boeckli et al., 2012; Etzelmüller et al., 2001; Gruber & Hoelzle, 2001) and to capture the multivariate nature of periglacial processes at landscape‐scale by documenting how their distribution and dynamics are influenced by environmental factors (Hjort & Luoto, 2011, 2013; Hjort et al., 2014; Karjalainen et al., 2019; Rudy et al., 2017). By statistically identifying the variables influencing the ground thermal regime and periglacial processes, it becomes possible to better explain their current distribution and predict their future evolution based on climate change scenarios (Aalto et al., 2017; Blois et al., 2013; Hjort et al., 2018; Karjalainen et al., 2020). However, previous research has been primarily based on in‐situ measurements (e.g., ground temperature from boreholes) or mapped landforms (e.g., inventory of solifluction lobes and palsas) and few studies have integrated advanced remote sensing data documenting periglacial activity, such as InSAR‐based ground velocity.…”

Regional Morpho-Kinematic Inventory of Slope Movements in Northern Norway

“…Rock glaciers, defined here as creeping permafrost landforms consisting of an ice/rock mixture (Berthling, 2011), are often used as a proxy for permafrost occurrence or paleo-permafrost extent (Lilleøren and Etzelmüller, 2011;Scotti et al, 2013;Etzelmüller et al, 2020;Karjalainen et al, 2020). In mountainous areas where large topographic variability and site-specific conditions determine the local occurrence of permafrost, rock glacier inventories are valuable to complement global kilometric-resolution permafrost products (Obu et al, 2019).…”