Climate change is transforming the ice-free areas of Antarctica, leading to rapid changes in terrestrial ecosystems. These areas represent <0.5% of the continent and coincide with the most anthropogenically pressured sites, where the human footprint is a source of contamination. Simultaneously, these are the locations where permafrost can be found, not being clear what might be the consequences following its degradation regarding trace element remobilisation. This raises the need for a better understanding of the natural geochemical values of Antarctic soils as well as the extent of human impact in the surroundings of scientific research stations. Permafrost thaw in the Western Antarctic Peninsula region and in the McMurdo Dry Valleys is the most likely to contribute to the remobilisation of toxic trace elements, whether as the result of anthropogenic contamination or due to the degradation of massive buried ice and ice-cemented permafrost. Site-specific locations across Antarctica, with abandoned infrastructure, also deserve attention by continuing to be a source of trace elements that later can be released, posing a threat to the environment. This comprehensive summary of trace element concentrations across the continent's soils enables the geographical systematisation of published results for a better comparison of the literature data. This review also includes the used analytical techniques and methods for trace element dissolution, important factors when reporting low concentrations. A new perspective in environmental monitoring is needed to investigate if trace element remobilisation upon permafrost thaw might be a tangible consequence of climate change.

Subsea pipelines in Arctic environments face the risk of damage from ice gouging, where drifting ice keels scour the seabed. To ensure pipeline integrity, burial using methods like ploughs, mechanical trenchers, jetting, or hydraulic dredging is the conventional protection method. Each method has capabilities and limitations, resulting in different trench profiles and backfill characteristics. This study investigates the influence of these trenching methods and their associated trench geometries on pipeline response and seabed failure mechanisms during ice gouging events. Using advanced large deformation finite element (LDFE) analyses with a Coupled Eulerian-Lagrangian (CEL) algorithm, the complex soil behavior, including strain-rate dependency and strainsoftening effects, is modeled. The simulations explicitly incorporate the pipeline, enabling a detailed analysis of its behavior under ice gouging loads. The simulations analyze subgouge soil displacement, pipeline displacement, strains, and ovalization. The findings reveal a direct correlation between increasing trench wall angle and width and the intensification of the backfill removal mechanism. Trench geometry significantly influences the pipeline's horizontal and vertical displacement, while axial displacement and ovalization are less affected. This study emphasizes the crucial role of trenching technique selection and trench shape design in mitigating the risks of ice gouging, highlighting the value of numerical modeling in optimizing pipeline protection strategies in these challenging environments.

With polar amplification warming the northern high latitudes at an unprecedented rate, understanding the future dynamics of vegetation and the associated carbon-nitrogen cycle is increasingly critical. This study uses the dynamic vegetation model LPJ-GUESS 4.1 to simulate vegetation changes for a future climate scenario, generated by the EC-Earth3.3.1 Earth System model, with the forcing of a 560 ppm CO2 level. Using climate output from an earth system model without coupled dynamic vegetation, to run a higher resolution dynamic vegetation standalone model, allows for a more in depth exploration of vegetation changes. Plus, with this approach, the drivers of high latitude vegetation changes are isolated, but there is still a complete understanding of the climate system and the feedback mechanisms that contributed to it. Our simulations reveal an uneven greening response. The already vegetated Southern Scandinavia and western Russia undergo a shift in species composition as boreal species decline and temperate species expand. This is accompanied by a shift to a carbon sink, despite higher litterfall, root turnover and soil respiration rates, suggesting productivity increases are outpacing decomposition. The previously barren or marginal landscapes of Siberia and interior Alaska/Western Canada, undergo significant vegetation expansion, transitioning towards more stable, forested systems with enhanced carbon uptake. Yet, in the previously sparsely vegetated northern Scandinavia, under elevated CO2 temperate species quickly establish, bypassing the expected boreal progression due to surpassed climate thresholds. Here, despite rising productivity, there is a shift to a carbon source. The deeply frozen soils in central Siberia resist colonisation, underscoring the role of continuous permafrost in buffering ecological change. Together, these results highlight that CO2 induced greening does not always equate to enhanced carbon sequestration. The interplay of warming, nutrient constraints, permafrost dynamics and disturbance regimes creates divergent ecosystem trajectories across the northern high latitudes. These findings illustrate a strong need for regional differentiation in climate projections and carbon budget assessments, as the Arctic's role as a carbon sink may be more heterogeneous and vulnerable than previously assumed.

The Qinghai-Tibetan Plateau (QTP) and the Arctic are prime examples of permafrost distribution in high-altitude and high-latitude regions. A nuanced understanding of soil thermal conductivity (STC) and the various influencing factors is essential for improving the accuracy of permafrost simulation models in these areas. Nevertheless, no comparative analysis of STC between these two regions has been conducted. Therefore, this study aims to investigate the characteristics and influencing factors of STC at varying depths within the active layer (5 to 60 cm) during freezing and thawing periods in the QTP and the Arctic, using the regional-scale STC data products simulated through the XGBoost method. The findings indicate the following: (1) the mean STC of permafrost in the QTP is higher than that in the Arctic permafrost region. The STC in the QTP demonstrates a declining trend over time, while the Arctic permafrost maintains relative stability. The mean STC values in the QTP permafrost region during the thawing period are significantly higher than those during the freezing period. (2) STC of the QTP exhibits a fluctuating pattern at different depths, in contrast, the average STC value in the Arctic increases steadily with depth, with an increase rate of approximately 0.005 Wm-1 K-1/cm. (3) The analysis of influencing factors revealed that although moisture content, bulk density, and porosity are the primary drivers of regional variations in STC between the QTP and the Arctic permafrost, moisture elements in the QTP region have a greater influence on STC and the effect is stronger with increasing depth and during the freeze-thaw cycles. Conversely, soil saturation, bulk density, and porosity in the Arctic have significant impacts. This study constitutes the first systematic comparative analysis of STC characteristics.

The accelerated warming in the Arctic poses serious risks to freshwater ecosystems by altering streamflow and river thermal regimes. However, limited research on Arctic River water temperatures exists due to data scarcity and the absence of robust methodologies, which often focus on large, major river basins. To address this, we leveraged the newly released, extensive AKTEMP data set and advanced machine learning techniques to develop a Long Short-Term Memory (LSTM) model. By incorporating ERA5-Land reanalysis data and integrating physical understanding into data-driven processes, our model advanced river water temperature predictions in ungauged, snow- and permafrost-affected basins in Alaska. Our model outperformed existing approaches in high-latitude regions, achieving a median Nash-Sutcliffe Efficiency of 0.95 and root mean squared error of 1.0 degrees C. The LSTM model learned air temperature, soil temperature, solar radiation, and thermal radiation-factors associated with energy balance-were the most important drivers of river temperature dynamics. Soil moisture and snow water equivalent were highlighted as critical factors representing key processes such as thawing, melting, and groundwater contributions. Glaciers and permafrost were also identified as important covariates, particularly in seasonal river water temperature predictions. Our LSTM model successfully captured the complex relationships between hydrometeorological factors and river water temperatures across varying timescales and hydrological conditions. This scalable and transferable approach can be potentially applied across the Arctic, offering valuable insights for future conservation and management efforts.

The fine-scale controls of active layer dynamics remain poorly understood, particularly at the southern boundary of continuous permafrost. We examined how environmental conditions associated with upland tundra heath, open graminoid fen, and palsa/peat plateau landforms affected active layer thermal regime (timing, magnitude, and rate of thaw) in a subarctic peatland in the Hudson Bay Lowlands, Canada. A significant increase in active layer thaw depth was evident between 2012 and 2024. Within-season thaw patterns differed among landforms, with tundra heath exhibiting the highest thaw rates and soil temperatures, succeeded by fen and palsa. Air temperature mediated by soil properties, topography, and vegetation affected thaw patterns. The increased thermal conductivity of gravel/sandy tundra heath soils exerted a more pronounced influence on thaw patterns relative to fens and palsas, both of which had a thicker organic layer. Near-surface soil moisture was the lowest in tundra, followed by palsas, and fens. Increased soil moisture impeded active layer thaw, likely due to a combination of soil surface evaporation and meltwater percolation. These findings elucidate the relationship between the biophysical properties of landform features and climate, revealing their role in influencing active layer thaw patterns in a subarctic ecosystem.

The paper presents the strategic project of Tomsk State University devoted to studying the carbon cycle in the arctic land-shelf system. The obtained carbon cycle characteristics should be used for global climate model correction. The main objective of the consortium is to obtain new data on the variability of climatic and biological factors of various ecosystems, monitor them, and create archives of data on their dynamics. The area of the project includes the basins of the Great Siberian Rivers, and the shelf of the adjacent Arctic seas. A consortium of approximately twenty universities and research institutions was formed to study the carbon cycle in various environments, including seas, rivers, wetlands, and permafrost. In addition to studying the carbon cycle, the project also aims to develop methods for carbon sequestration and ecosystems remediation. One of such methods was developed for the assessment and cleanup of bottom sediments from oil and petroleum products as well as other hydrophobic contaminants and has been patented and tested in a series of field trials. Several special monitoring methods are described, such as novel sampling and sample laboratory processing techniques to assess microplastics in the environment; and holographic methods for underwater monitoring of the plankton behavior for early bioindication of hazards in the water area. This is particularly relevant for areas with dangerous objects, such as nuclear power plants, oil platforms, and gas pipelines. The methods of math modeling of the impact of climate change and anthropogenic factors on indigenous and local population lives were used.

The Arctic experiences rapid climate change, but our ability to predict how this will influence plant communities is hampered by a lack of data on the extent to which different species are associated with particular environmental conditions, how these conditions are interlinked, and how they will change in coming years. Increasing temperatures may negatively affect plants associated with cold areas due to increased competition with warm-adapted species, but less so if local temperature variability is larger than the expected increase. Here we studied the potential drivers of vegetation composition and species richness along coast to inland and altitudinal gradients by the Nuuk fjord in western Greenland using hierarchical modelling of species communities (HMSC) and linear mixed models. Community composition was more strongly associated with random variability at intermediate spatial scales (among plot groups 500 m apart) than with large-scale variability in summer temperature, altitude or soil moisture, and the variation in community composition along the fjord was small. Species richness was related to plant cover, altitude and slope steepness, which explained 42% of the variation, but not to summer temperature. Jointly, this suggests that the direct effect of climate change will be weak, and that many species are associated with microhabitat variability. However, species richness peaked at intermediate cover, suggesting that an increase in plant cover under warming climatic conditions may lead to decreasing plant diversity.

Permafrost degradation is one of the most significant consequences of climate change in the Arctic. During summers, permafrost degradation is evident with cryospheric hazards like retrogressive thaw slumps (RTSs) and active layer detachment slides (ALDs). In parallel, the Arctic has become a popular tourist destination for nature-based activities, with summer being the peak touristic season. In this context, cryospheric hazards pose potential risks for tourists' presence in Arctic national parks and wilderness in general, like in the Yukon. This essay provides the basis for investigating further periglacial, geomorphological and tourism intersections, highlighting the critical need for future interdisciplinary research on thawing permafrost impacts. More so, this requires moving beyond the predominant focus on permafrost impacts on infrastructure and to also consider the direct threats posed to human physical presence in Arctic tourist destinations affected by permafrost degradation. Such interdisciplinary approach is critical not only to mitigate risks, but also to provide policy- and decision-makers with valuable insights for implementing measures and guidelines.

The Net Ecosystem Carbon Balance (NECB) is a crucial metric for understanding integrated carbon dynamics in Arctic and boreal regions, which are vital to the global carbon cycle. These areas are associated with significant uncertainties and rapid climate change, potentially leading to unpredictable alterations in carbon dynamics. This mini-review examines key components of NECB, including carbon sequestration, methane emissions, lateral carbon transport, herbivore interactions, and disturbances, while integrating insights from recent permafrost region greenhouse gas budget syntheses. We emphasize the need for a holistic approach to quantify the NECB, incorporating all components and their uncertainties. The review highlights recent methodological advances in flux measurements, including improvements in eddy covariance and automatic chamber techniques, as well as progress in modeling approaches and data assimilation. Key research priorities are identified, such as improving the representation of inland waters in process-based models, expanding monitoring networks, and enhancing integration of long-term field observations with modeling approaches. These efforts are essential for accurately quantifying current and future greenhouse gas budgets in rapidly changing northern landscapes, ultimately informing more effective climate change mitigation strategies and ecosystem management practices. The review aligns with the goals of the Arctic Monitoring and Assessment Program (AMAP) and Conservation of Arctic Flora and Fauna (CAFF), providing important insights for policymakers, researchers, and stakeholders working to understand and protect these sensitive ecosystems.