Thermokarst is the process whereby the thawing of ice-rich permafrost ground causes land subsidence, resulting in development of distinctive landforms. Accelerated thermokarst due to climate change will damage infrastructure, but also impact hydrology, ecology and biogeochemistry. Here, we present a circumpolar assessment of the distribution of thermokarst landscapes, defined as landscapes comprised of current thermokarst landforms and areas susceptible to future thermokarst development. At 3.6 × 106 km2, thermokarst landscapes are estimated to cover ∼20% of the northern permafrost region, with approximately equal contributions from three landscape types where characteristic wetland, lake and hillslope thermokarst landforms occur. We estimate that approximately half of the below-ground organic carbon within the study region is stored in thermokarst landscapes. Our results highlight the importance of explicitly considering thermokarst when assessing impacts of climate change, including future landscape greenhouse gas emissions, and provide a means for assessing such impacts at the circumpolar scale.

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Circumpolar distribution and carbon storage of thermokarst landscapes

Deep Yedoma permafrost: A synthesis of depositional characteristics and carbon vulnerability

Sedimentary characteristics and origin of the Late Pleistocene Ice Complex on north-east Siberian Arctic coastal lowlands and islands – A review

Local observations indicate that climate change and shifting disturbance regimes are causing permafrost degradation. However, the occurrence and distribution of permafrost region disturbances (PRDs) remain poorly resolved across the Arctic and Subarctic. Here we quantify the abundance and distribution of three primary PRDs using time-series analysis of 30-m resolution Landsat imagery from 1999 to 2014. Our dataset spans four continental-scale transects in North America and Eurasia, covering ~10% of the permafrost region. Lake area loss (−1.45%) dominated the study domain with enhanced losses occurring at the boundary between discontinuous and continuous permafrost regions. Fires were the most extensive PRD across boreal regions (6.59%), but in tundra regions (0.63%) limited to Alaska. Retrogressive thaw slumps were abundant but highly localized (<10−5%). Our analysis synergizes the global-scale importance of PRDs. The findings highlight the need to include PRDs in next-generation land surface models to project the permafrost carbon feedback.

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Remote sensing quantifies widespread abundance of permafrost region disturbances across the Arctic and Subarctic

Last glacial-interglacial vegetation and environmental dynamics in southern Siberia: chronology, forcing and feedbacks.

Ice-rich permafrost deposits and their isotopic composition were studied at four sites in the western foreland of the Verkhoyansk Mountains, Central Yakutia. The isotopic composition of ice wedges formed in alluvial and loess-like sediments generally reflects the palaeoclimate of winter conditions. The middle Weichselian Ice Complex developed around 41 ka 14C BP during a period with colder winters than today. Similarly severe conditions are reflected in the late Weichselian Ice Complex from around 20 ka to 13 ka 14C BP. The transition to the Holocene is characterised by increases of 5‰ and 35‰ in δ18O and δD, respectively. This warming is documented in wedge ice, which grew between 8.5 and 4.5 ka BP. Towards the late Holocene and sub-recent times, a climatic deterioration is recorded, reflected by lighter isotopic composition of ice wedges, which developed between 1.2 ka and 0.7 ka 14C BP.

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Palaeoclimate signals as inferred from stable-isotope composition of ground ice in the Verkhoyansk foreland, Central Yakutia

Ice-rich permafrost in the Yana Upland has been investigated. The composition and structure of the permafrost has been determined. Their role in thermal denudation processes has been examined. The response of the ice-rich permafrost to recent climate change has been assessed.

Ice-rich Permafrost and thermal denudation in the Batagay area (Yana Upland, East Siberia)

Quaternary deposits of Bol'shoy Lyakhovsky Island

Landforms and degradation pattern of the Batagay thaw slump, Northeastern Siberia

Climate change and the degradation of permafrost prove to be severe challenges for humanity. At present, the northern communities and those living in rural areas are already facing the consequences. This article is based on field research conducted in the Yunkyur, Olyokminsky, and Amginsky Districts of Sakha Republic (Yakutia) during 2018–2020. These settlements have one of the richest agricultural traditions in the region; however, the inhabitants of these villages now face serious consequences of permafrost degradation. The authors rely on a mixed set of methods and approaches, including sociological surveys, expert and in-depth interviewing, and appropriate archival and museum materials. Methodology of remote sensing and landscape–geocryological research was integrated. The resulting studies made it possible to demonstrate increasingly widespread thermokarst processes in the key areas studied. The authors determined that the degradation of permafrost has led to problems with the safety and development of the housing stock, especially deformation of houses and outbuildings, and reduction of areas suitable for construction. Territories affected by thermokarst also drop out of agricultural use. Finally, the authors identify some adaptation mechanisms to mitigate the effects of changes in permafrost landscapes.

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Igor Syromyatnikov

Papers

Palaeoclimate signals as inferred from stable-isotope composition of ground ice in the Verkhoyansk foreland, Central Yakutia

Ice-rich Permafrost and thermal denudation in the Batagay area (Yana Upland, East Siberia)

Quaternary deposits of Bol'shoy Lyakhovsky Island

Landforms and degradation pattern of the Batagay thaw slump, Northeastern Siberia

Influence of Permafrost Landscapes Degradation on Livelihoods of Sakha Republic (Yakutia) Rural Communities