Spatial distribution, retention and transport of hexachlorobutadiene in Arctic permafrost soils.

Occurrence and characteristics of organochlorine pesticides from soils due to permafrost thaw slumping on the Qinghai-Tibetan Plateau.

Larix gmelinii growth limitation shifts from nitrogen availability to drought under warming and permafrost degradation

Climate warming advances the start of the growing season and enhances carbon uptake on the Qinghai-Tibet Plateau, primarily through the direct effects of air temperature and precipitation. However, the role of spring soil moisture dynamics driven by freeze-thaw processes remains underexplored. Here, using multi-source data from 32 Qinghai-Tibet Plateau sites (2003-2024), we develop a framework to decouple and quantify the moisture-limit relief from freeze-thaw-driven soil moisture return(ESMR) and concurrent precipitation effect(Eprec). Across study sites, soil moisture return contributes 20.7% ± 2.1% (mean ± SD) of the start of the growing season advance since 2003, surpassing the precipitation effect and air temperature, underscoring the role of pre-freezing moisture return in advancing start of the growing season in the following spring. At sites with active layer thickness exceeding 2.2 m, the ESMR exhibits ~31% higher sensitivity to surface soil moisture compared to sites with thinner active layer thickness. As active layer thickness deepens, the influence of soil moisture dynamics in the middle and lower active layers, associated with permafrost degradation, may gradually weaken in regulating start of the growing season. Our findings identify freeze-thaw soil moisture dynamics as an important, previously underappreciated control on start of the growing season and spring carbon uptake on the warming Qinghai-Tibet Plateau.

In recent decades, the Arctic has warmed at a rate that significantly exceeds the global mean, a phenomenon commonly referred to as Arctic amplification. Studies consistently show that Arctic temperatures are increasing at a rate roughly two to four times the global average, highlighting the exceptional sensitivity of northern environments to ongoing climatic change. Permafrost thaw is increasingly destabilizing high-latitude and high- altitude landscapes, giving rise to a range of slope failures with growing implications for ecosystems, infrastructure, and human activity. This dissertation examines thaw-driven mass-wasting processes across multiple spatial scales, focusing on retrogressive thaw slumps (RTSs) and active-layer detachment failures (ALDs) as dominant expressions of permafrost degradation under a warming climate. Integrating circumpolar susceptibility modeling, regional comparative analysis, applied infrastructure exposure assessment, and a tourism focused case study, the thesis develops a multiscale framework for understanding where thaw-related slope instability is likely to occur, how controlling factors vary among permafrost landscapes, and why these processes matter for society. At the circumpolar scale, statistical susceptibility modeling identifies consistent hemispheric patterns in RTS occurrence associated with climatic conditions and terrain settings commonly linked to ice-rich permafrost. Comparative regional analyses demonstrate that RTSs occupy distinct environmental envelopes throughout cold regions, highlighting pronounced environmental heterogeneity between regions. Regional-scale modeling of ALDs across Alaska and northwestern Canada reveals strong associations with slope morphology, cold-climate conditions, and fine-grained soils and shows extensive overlap between susceptible terrain and critical infrastructure networks. A local-scale synthesis in Yukon protected areas further illustrates that thaw-driven geomorphic hazards intersect with tourism, heritage, and governance, extending permafrost risk beyond infrastructure and settlements to transient human presence. Collectively, the results show that thaw-related slope failures are governed by consistent classes of environmental controls, such as climate and topography, whose expression and consequences are fundamentally scale-dependent. By linking physical susceptibility with environmental heterogeneity and patterns of human use, this dissertation advances an integrated perspective on permafrost thaw as a coupled socioenvironmental phenomenon. The findings provide a scientific basis for anticipated impacts of accelerating permafrost degradation and support the development of multiscale adaptation strategies in rapidly changing cryospheric environments.

Abstract. Permafrost degradation significantly affects the stability of rockwalls in high altitude regions. Monitoring rockwall permafrost is essential for assessing potential geohazards. While borehole temperature measurements are the most direct permafrost monitoring approach, they lack sufficient spatial representation in such highly heterogeneous ground conditions. Conversely, geoelectrical measurements can provide more comprehensive insights into these complex patterns and dynamics. This study investigates the permafrost dynamics and intends to detect potential hydrogeological processes at the Aiguille du Midi (3842 m a.s.l. (meter above sea level), French Alps) using repeated and Automated-Electrical Resistivity Tomography (A-ERT) approaches, covering a period of 3.5 years (June 2020–December 2023). A total of three geoelectrical profiles have been installed on three faces of the Aiguille du Midi (N–W, S and E). An automated acquisition system for permanent resistivity monitoring and remote data acquisition is implemented. A time-lapse inversion technique is employed to get the temporal and spatial variations of electrical resistivity at seasonal and interannual time scales. The data revealed significant variations in active layer thickness across rock faces, along with a slight decrease in electrical resistivity at depth, indicating permafrost warming over time. However, they did not provide clear evidence of water pressurization in rock fractures. Using a petrophysical model, calibrated with laboratory measurements of the temperature dependence of electrical resistivity of granite sample, we estimated the temperature within the frozen zone from the resistivity measurements, under favorable conditions at surface in summer and autumn. Validation against direct temperature measurements in a 10 m depth borehole along the NW profile indicates a mean absolute error less than 1 °C within the frozen zone. This research underscores the efficacy of ERT as a promising, non-invasive tool for quantitative monitoring of permafrost dynamics in Alpine environments. It also reveals challenges associated with conducting A-ERT in high mountain rockwalls where the contact resistance is very high (∼500 kΩ) and sometimes intermittent due to factors such as thunder strikes and rockfalls.

Abstract The polar region is sensitive to climate change, with concerns about the effects on ecosystems and human society. In particular, the thawing of permafrost associated with rising temperatures accelerates the microbial decomposition of organic carbon in the soil, leading to greenhouse gas emissions. Thermokarst is a landform process formed by thawing ice-rich permafrost and subsidence of the ground surface. This landform is an indicator of permafrost degradation; thus, evaluating the distribution of thermokarst is essential for understanding the impact on Arctic regions. Although assessing the thermokarst has been a labor-intensive task because of its widespread occurrence in the Arctic, automatic detection using deep learning and remote sensing techniques has been applied. However, the cost of creating training data for the specific area was challenging because thermokarst size and shape varied by region. Here, we classified thermokarst from satellite images using a recently developed method, the chopped picture method, which is suitable for identifying ambiguous and amorphous objects such as the thermokarst. This study uses high-resolution panchromatic and pan-sharpened images in eastern Siberia to evaluate the effects of differences in satellite images on classification accuracy. The training and test images were divided into 60 pixels in height and width, and each cell was classified into two categories: thermokarst topography or others. In addition, we used Global Map Data to calculate the percentage of thermokarst topography for each slope orientation (south or north) to identify the environmental conditions that facilitate the development of this topography. Results showed that our approach could clearly and automatically distinguish developed thermokarst from other landforms such as forests, lakes, and urban. Classification of thermokarst topography in panchromatic and pan-sharpened images indicated that automatic detection was possible in both images. Additionally, thermokarst topography was distributed on south-oriented slopes rather than north. This method will achieve low-cost automatic detection of thermokarst through the use of satellite data and AI. With the increase of small satellites, opportunities to utilize satellite images for observations in Arctic research will expand. Our approach will contribute to environmental monitoring in the Arctic by enabling the automatic mapping of thermokarst.

• Ice and peat-rich permafrost degrades slowly; • Peat and ground ice are as an insulation effect; • Ground ice melting regulate surface settlement and permafrost stability. Warming climate has led to permafrost degradation at varying rates, which can accelerate the release of permafrost carbon and ground ice melt. However, these impacts are not clear and the sensitivity of ice and peat-rich permafrost to climate change has not been quantified. We choose an observing site named EboA, located on ice and peat-rich permafrost on the northeastern Qinghai-Tibet Plateau, in combination with the CryoGrid community model to analyze the long-term permafrost dynamics during 1941–2023. Permafrost has been degrading, though gradually, with a soil temperature increase of 0.1°C/10a and active layer increases of 0.03 m/10a, reaching a maximum of 0.88 m. Approximately 19 mm of subsidence has occurred due to ground ice melting. This permafrost degradation is relatively small and slower than in other regions because organic carbon has a lower thermal conductivity and higher ice content, acting as an insulating layer. During the warm season, the heat exchange between the ground and the atmosphere is reduced, while in the cold season the high ground ice content facilitates heat transfer and exchange. Thus, a new understanding of ice-carbon coupling in regulating permafrost changes is presented.

Permafrost degradation: A critical driver of aboveground carbon sink loss in China's boreal forests

While the impacts of permafrost degradation on Eurasian river discharge are well-documented, a systematic understanding of how these impacts vary across latitudes—critical for predicting continental water security and Arctic freshwater export—remains lacking. This study bridges this gap by analyzing latitudinal gradients in extreme and mean monthly discharges—lowest (LD), mean (MD), and highest (HD) monthly discharge—across 22 major Eurasian permafrost rivers, integrating snowmelt dynamics and winter river ice dynamics with watershed energy-water budgets. We find pronounced latitudinal gradients in hydrological responses. The most robust change is a pan-Eurasian increase in winter baseflow (LD, 5%–8% per decade), primarily driven by warming-induced river ice (24-d shorter freezing duration; 8.2% volume decline contributing 19.6% to LD rise). In contrast, high (HD) and mean (MD) discharge trends show distinct zonal divergence: significant increases in precipitation-driven low latitudes, a post-1990s reversal from decline to increase in mid-latitudes, and muted but more variable trends in high latitudes where precipitation increases are offset by evapotranspiration and storage changes. The late 1990s marked a critical shift, synchronizing abrupt hydrological changes with contemporaneous shifts in regional climate forcing and cryospheric processes. The identified latitudinal patterns and their underlying mechanisms provide a predictive framework for anticipating future hydrological extremes—from winter water scarcity to flood risks—in these vulnerable basins in a warming world.

Abstract. Water flow in high mountain rock walls is crucial for landscape evolution and slope stability. However, the timing, quantity, and sources of this flow remain poorly understood. In the Mont Blanc massif, tunnels at the Aiguille du Midi peak (3842 m) provide direct access to steep permafrost-affected rock walls. Between May 2022 and October 2023, we monitored water flowing from fractures using a real-time system that measured flow rate, temperature, electrical conductivity, and fluorescence of tracers, alongside meteorological data and ground surface temperatures. The results indicate high surface–subsurface connectivity. The water source is primarily snowmelt, with additional inputs from late-summer rainfall. Electrical conductivity, stable isotopes, and recession curve analysis suggest another source of older subsurface ice. Flow onset was closely tied to air temperatures, with steady diurnal fluctuations appearing once rock surface temperatures exceeded 0 °C. Lag times between daily peaks of flow rate and peaks of air and ground surface temperatures of 3–9 and 0–3 h, respectively, point to rapid unsaturated infiltration conditions. Distinct flow regimes observed in two adjacent fracture systems reflect a complex, heterogeneous network, including sediment-filled fractures with a delayed response. Significant flow rates (often > 10 L h−1) and water temperature often exceeding 5 °C, suggest significant heat transfer by advection, capable of enhancing permafrost degradation. This study provides rare direct observations of fracture flow dynamics in steep permafrost rocks and improves our understanding of water routing and its response to atmospheric forcing. The findings offer valuable constraints for coupled hydrothermal models, permafrost-related hazard assessments, and the potential impact of climate change.

Nitrous oxide (N2O) contributes to stratospheric ozone depletion and global warming. Knowledge about microbial formation and consumption of N2O in old permafrost remains limited. Permafrost samples collected on the East Siberian Sea coast of Russia from a single borehole at depths of 5.4 and 16.9m, which showed presence of nitrogen substances and nitrogen cycling genes, were used to establish microcosms supplemented with NO3- and N2O to assess denitrification and N2O consumption at 4°C and 20°C. Rapid N2O formation was observed in NO3--supplemented microcosms, but N2O consumption was slow and incomplete over a 1-year incubation in all microcosms. Twenty-three qualified metagenome-assembled genomes (MAGs) harboring genes involved in NO3- and/or N2O reduction were recovered from both NO3-- and N2O-supplemented microcosms. Twenty MAGs represent novel taxa. Four MAGs, two of each from NO3-- and N2O-supplemented microcosms, contained nosZ genes indicating N2O consumption potential, however the complete denitrification (i.e. NO3-→N2) gene sets were not detected in these MAGs. Though, N2O production exceeded N2O consumption in NO3--supplemented microcosms at 4°C. Our microcosm experiments suggest N2O formation surpasses its consumption in newly thawed ∼120 kyr old permafrost, emphasizing the importance of using integrated approaches to assess and predict N turnover in response to permafrost degradation.

Abstract The retrogressive thaw slumps (RTS), a prevalent form of thermokarst hazard in permafrost regions, are increasing in both number and extent under contemporary changing environments. On the Qinghai‐Tibet Plateau, RTS threaten transportation infrastructure and disrupt ecosystems. However, the combined influence of hydroclimatic drivers on RTS subsidence remains poorly understood. We therefore examine the relationship between surface displacement and precipitation under varying land surface temperature (LST) conditions in Beiluhe region. Our findings reveal an average seasonal displacement amplitude of 27 mm and a mean annual subsidence of 12–19 mm across RTS. When LST remains below approximately 0°C, faster annual subsidence is linked to drier years. In contrast, when LST exceeds 0°C, faster subsidence is associated with wetter years. These results provide new insights into the coupled dynamics of surface displacement, precipitation, and LST in RTS subsidence, enhancing our understanding of permafrost degradation processes amid climate crisis.

Abstract Permafrost degradation in Arctic and Subarctic regions, accelerating due to rapid climate change, exposes vast extents of ice- and organic matter-rich soils directly to the atmosphere. This ancient permafrost is known to harbor metabolically active microbes, including potentially harmful pathogens that have survived for thousands of years under extreme environmental conditions. The release and subsequent long-range dispersal of these organisms via atmospheric transport presents a significant, yet often neglected, pathway for novel disease emergence. Here, we develop a quantitative risk framework to geographically identify downwind areas in the Palearctic region potentially reached by air-transported pathogens emerging from Siberian retrogressive thaw slumps. We simulate air-mass trajectories to derive a hazard metric that accounts for the accelerating rate of slumps thawing. This hazard is coupled with the distribution of humans, major crops, or livestock representing the exposure term. We evaluate the associated health risk by introducing a novel hierarchical Pareto ranking approach, which prioritizes locations based on the joint effect of hazard and exposure without applying subjective weights. The results indicate that high risks are not only concentrated near source areas, but also extend to distant, densely populated urban centers in Russia, China, and Japan, and impact key agricultural regions. Given the increasing rates of permafrost thawing and the consequent risk of exposure of distant host populations, we call for a better characterization of the pathosphere in Arctic frozen grounds and for the development of credible models to identify and monitor specific One Health risk hotspots for plant, animal, and human populations.

Permafrost on the Tibetan Plateau (TP) exhibits a pronounced temporal offset between atmospheric warming and subsurface thermal changes, yet its characteristic timescales, spatial patterns, and environmental drivers remain poorly quantified. This complicates the interpretation of climate forcing and ground temperature relationships, increasing uncertainty in projections of permafrost degradation and carbon feedbacks. Here, we combine in-situ records from 54 boreholes (2001–2020) with a high-resolution meteorological forcing dataset (TPMFD) to characterize the apparent timescale of permafrost thermal memory on the TP. Analyses reveal a median multi-year to decadal offset of approximately 8–11 years for active layer thickness and temperatures at the permafrost table and at 10–15 m depth. This timescale shortens to 6–8 years in warm, humid southeastern margins and lengthens to 12–15 years in cold, arid northwestern interiors. Climatic factors explain 31–51% of its spatial variance, with air pressure and precipitation serving as dominant statistical contributors, reflecting large-scale climatic background conditions, while topography and soil moisture exert local controls. These offsets represent an emergent statistical timescale associated with cumulative thermal memory and energy integration in the permafrost system, indicating that ongoing permafrost degradation may continue even if near‑surface warming moderates.

Abstract The severity and frequency of tundra fires in Arctic permafrost landscapes is expected to increase with ongoing climate change. By burning the insulating organic layer of soils, tundra fires impact the soil thermal regime for underlying permafrost and can accelerate thaw in the years following the burn. In this paper, we address the scarcity of long-term studies on post-fire permafrost degradation in ice-wedge landscapes by using a space-for-time substitution analysis spanning a chronosequence (pseudo-time series) of up to 67 years of remote sensing data from Alaskan tundra fire scars. We use computer vision and graph analysis on high-resolution digital elevation models derived from airborne lidar of fire-affected areas in Western Alaska to investigate the effects of tundra fires on the post-fire development of microtopography and surface hydrology in polygonal ice-wedge landscapes. Our analysis indicates a modest overall trend toward recovery of polygonal surface structure over timescales of 70+ years, though considerable variability among fire scars highlights that post-fire trajectories are not uniform.

The degradation of permafrost and the higher number of heavy rainfall events increase geomorphic disturbance (GMD), affecting the vegetation establishment in high-elevation belts. To evaluate the effect of GMDs on vegetation development, it is essential to understand how species or plant groups respond to disturbances. In this study, we investigated vegetation establishment in undisturbed and disturbed plot pairs along elevational transects in the Austrian and Italian Central Alps. Differences in total vegetation cover, species diversity, the cover of different plant groups and the community weighted means of the Landolt indicator values were analysed using the Kruskal-Wallis test for non-parametric data and paired t-test for parametric data. Generalised additive models combined with a principal component analysis were applied to identify the significant environmental variables (e.g., inclination or precipitation) explaining the differences found. To assess species' plasticity, the three most abundant species (five individuals per plot) per undisturbed-disturbed pairs were collected on-site, and functional traits measured in the laboratory. Disturbed sites exhibited lower total vegetation cover, species number, cover of competitive species, dwarf shrubs, herbs and lichens. The cover of stress-tolerant, cryophilic species and herbs was higher in disturbed sites. The observed variations can be mainly explained by climatic, edaphic and topographic variables. The Stream Power Index as a disturbance proxy had a significant negative influence on the total vegetation cover and herb cover and a positive influence on bryophyte, dwarf shrub, and tree cover. Most collected species showed high trait plasticity, with disturbance primarily reducing plant height and specific leaf area. Synthesis: GMD was the key driver in relation to both vegetation cover and species richness. The cover of most functional plant groups as well as species plasticity was primarily affected by climatic factors, soil conditions and the presence of less acidic debris than by GMD.

The subject of the research is the generalization of pioneering experiences of a comprehensive approach to the socio-humanitarian study of the Russian Arctic, accumulated by the Arctic Research Center of the Institute of Humanities and Problems of Small Indigenous Peoples of the North, Siberian Branch of the Russian Academy of Sciences. The aim of the work is to systematize the results of many years of research on the history of the intellectual development of the high latitudes, the analysis of the transformation of the culture, economy, and identity of indigenous peoples, as well as the study of the mechanisms of adaptation of rural communities in Yakutia to natural and social challenges. For the first time in Russian historiography, a picture of the intellectual development of the Arctic has been reconstructed, including the contribution of the Academy of Sciences and expeditions. New directions have been developed—anthropology of cold and anthropology of traditional lifestyles. The settlement, demographics, reindeer husbandry, livelihoods, and identity of the Yukaghirs, Evenks, and Chukchi in the 20th and 21st centuries have been analyzed. The consequences of climate change (floods, degradation of permafrost) have been identified, and adaptive strategies have been generalized. The scope of application of the results encompasses the development of state programs for the socio-economic and cultural development of small indigenous peoples of the North, conducting ethnological expertise of industrial projects regarding the observance of their rights, creating educational courses on history, anthropology, and Arctic studies, as well as formulating regional policies in the context of climate change and technological transformation of the traditional habitat. The novelty of the research lies in the systematic comprehensive analysis of socio-humanitarian processes in the Asian Arctic based on the material of Yakutia from the perspectives of the anthropology of cold and the anthropology of traditional lifestyles, the introduction into scientific circulation of a significant array of previously unpublished archival and field materials, as well as in rethinking the "resources of cold" not only as a limiting factor but also as an adaptive factor that opens additional opportunities for the survival and development of the local population. The conclusions of the work indicate that the quarter-century activity of the Arctic Research Center has confirmed the effectiveness of an interdisciplinary approach. Traditional knowledge and adaptive mechanisms of indigenous peoples possess a high potential for resilience, allowing for the preservation of the foundations of traditional lifestyles. The developed anthropological approaches create a basis for scientifically grounded recommendations for the sustainable development of Arctic communities in the face of contemporary challenges.

Abstract Accurate flood estimation in snow-dominated and high-latitude regions remains challenging due to complex interactions among rainfall, snowmelt, and rain-on-snow (ROS) processes, which are not captured in conventional precipitation-based intensity-duration-frequency (PREC-IDF) curves. This study evaluates the Next-Generation IDF (NG-IDF) framework, an extension of PREC-IDF that incorporates total water available for runoff (rainfall plus snowmelt), in two contrasting Alaskan watersheds of Department of Defense (DoD) significance: the Little Chena River Basin (LCRB) in interior Alaska, a tributary of the Chena River that flows through Fort Wainwright and near Eielson Air Force Base, and the Upper Ship Creek Basin (USCB), which drains Joint Base Elmendorf-Richardson near Anchorage. Using long-term Snow Telemetry (SNOTEL) observations and event-based rainfall-runoff modeling, NG-IDF and PREC-IDF flood estimates were compared against observation-based flood frequency analyses. Results show that NG-IDF consistently reduces flood-estimation bias by 15%–20% relative to PREC-IDF, particularly for snowmelt- and ROS-dominated events. In the interior LCRB, permafrost conditions can amplify flood responses during snowmelt events, an effect not explicitly represented in standard design tools. These findings demonstrate that NG-IDF provides a more physically consistent and transferable framework for flood estimation in cold regions, with potential relevance to mission-critical DoD installation resilience. Projected increases in ROS frequency and permafrost degradation across Alaska further emphasize the need to integrate physics-based hydrologic models that explicitly represent snow and permafrost processes to enhance infrastructure resilience and operational readiness for military and other critical assets.

Abstract Freeze-thaw cycles, hydrology, soil mixing, and permafrost degradation shape landscape patterns in permafrost regions, forming unvegetated or sparsely vegetated landforms with varied topography. These features, which we refer to as unvegetated thermokarst polygons, result from permafrost thaw and may play a critical role in Arctic greenhouse gas (GHG) dynamics by unlocking vast amounts of carbon stored in permafrost regions. However, their spatial extent remains uncertain due to their variable size (∼0.5–15 m) and the challenges of detecting them in heterogeneous landscapes such as polygonal tundra. This study assesses the extent of unvegetated thermokarst polygons near Utqiaġvik, Alaska, using imaging spectroscopy and lidar data with a 1 m spatial resolution from the National Ecological Observing Network airborne observation platform on the joint-basis of a linear spectral mixture analysis and lidar-based relief. Based on a confusion matrix evaluating threshold models of our analysis against field-based results, the model that performed with the greatest F 1 score (0.63), with balanced precision (0.71) and recall (0.57), estimated a 9.55% cover of unvegetated thermokarst polygons, or 380 000 m 2 total area of unvegetated thermokarst polygons within the study extent. Ground truth data from 52 sites revealed that the spectral mixture model correctly mapped ∼81% of unvegetated thermokarst polygons. Our results highlight the challenges and potential of detecting unvegetated thermokarst polygons in complex Arctic landscapes with high-resolution remote sensing. Although these features currently cover a small area in the study site, their relevance may grow with increased landscape changes and GHG dynamics under warm conditions. Moreover, their extent could be greater in areas with more active permafrost degradation, emphasizing the need for detection methods to monitor these critical landforms.