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In the context of climate change, research on frozen soils has attracted much attention in recent years, and numerous research papers have been published on these topics in the last decade. However, the present status and developmental trends in frozen soils research have not been reported systematically. Herein, a bibliometric analysis was conducted using 7,108 research papers on frozen soils published between 2010 and 2019. The results indicate that: (a) although the number of articles published increased from 432 in 2010 to 1,066 in 2019, the average number of citations per paper reached a maximum of 5.40 in 2014, and subsequently decreased to 2.99 in 2019; (b) China, the USA, and Canada ranked first to third in terms of total papers; (c) the most popular author keywords were boreal, tundra, Landsat, lakes, decomposition, dissolved organic carbon, permafrost thaw, and carbon cycle; and (d) the five most popular research topics in 2010–2019 were the characteristics and factors influencing frozen soils, the Arctic carbon cycle under the background of its complex environment, permafrost changes on the Qinghai–Tibet Plateau in the context of climate change, ancient frozen soils in various historical periods, and frozen soils in the Arctic. [ABSTRACT FROM AUTHOR]

The Kuparuk River, located on Alaska's North Slope, is one of the most studied rivers in the Arctic. For nearly 40 seasons, physical, chemical, and biological parameters have been monitored continuously in a 5 km, 4th‐order reach of the river during the short summer season when there is flow in this river. Flow decreases as the tundra begins to refreeze in the late autumn and these streams normally remain frozen until the spring freshet. The monitoring program has supported a 34‐year phosphorus enrichment experiment conducted by the Arctic Long Term Ecological Research (LTER) program. Enrichment with phosphorus dramatically changed the structure and function of the primary producer community in the fertilized reach, with cascading effects in higher trophic levels. The datasets generated by this experiment have revealed significant increases in flow‐weighted mean concentrations of nitrate and significant decreases in flow‐weighted mean concentrations of dissolved organic N and P over time. In this paper, we present an overview of the nutrient concentration, discharge, macroinvertebrate, and Arctic grayling population datasets we have collected. The purposes of these datasets are to track changes resulting from the enrichment experiment, support ancillary research on responses of an Arctic stream to climate warming and permafrost thaw, and to provide input and validation data for models to predict future changes in Arctic streams. [ABSTRACT FROM AUTHOR]

Climate change threatens many well‐preserved archaeological sites in the Arctic. The paper presents the first Arctic multi‐threat assessment focusing on the Nuuk region of Greenland. The results suggest that the majority of the 336 known archaeological sites are already exposed to impacts from microbial degradation, permafrost thaw and vegetation, and that these impacts will increase over the next 80 years. Additional impacts from coastal erosion are only noted at a limited number of sites due to a predominant consolidated and uplifting coast. The applied methods represent an important first step to identify threatened sites and emphasize important data limitations. [ABSTRACT FROM AUTHOR]

The Arctic has experienced rapid change associated with warming since the 1970s. The rapid retreat of the terrestrial cryosphere can release a large amount greenhouse gas from the permafrost regions into the air, and the sea ice decline will affect the CO2 and CH4 balance in the ocean. Changes in the Arctic provide feedback mechanisms that can also impinge on the global ocean's thermohaline circulation. During the past years, the overall natural processes in the Arctic have been studied although the magnitude and timing of carbon release from the cryosphere changes require further investigation. However, few studies have been conducted to link the natural and social systems in the Arctic. Scientists and policymakers must consider the coupled Arctic land, ocean, and social systems in their decisions for coping with climate change. Plain Language Summary: The Arctic is warming more than twice the global average. The Arctic is connected to the rest of the world through the climate system, it appears to be the first domino to fall, with the other dominoes pointing south. The Arctic science community and the people who live in the Arctic have known the rapid Arctic changes for a long time. It has been recognized that the cryosphere components are declining, and the carbon cycle in both the land and ocean will be affected by the cryosphere shrinkage. Despite some scientific breakthroughs, there are still major knowledge gaps in the Arctic carbon cycle. The policymakers at this stage are not only asking for more data about the Arctic changes, they also need scientific suggestions to cope with Arctic changes. The science community should work together to draw a full picture of the Arctic changes that include both natural and social systems. Key Points: The changing Arctic carbon cycle can affect global climateMore field observation should be carried out in the Arctic land and oceanThe Arctic land, ocean, and social domain should be considered as a system [ABSTRACT FROM AUTHOR]

An increased interest in Arctic environments, mainly due to climate change, has changed the conditions for permafrost research in recent years. This change has been accompanied by a global increase in scientific publications, as well as a trend towards open access publications. We have analyzed abstracts, titles and keywords for publications on permafrost from 1998 to 2017 to identify developments (topics, impact and collaboration) in the field of permafrost research in light of these changes. Furthermore, to understand how scientists build on and are inspired by each other's work, we have (a) developed citation networks from scientific publications on permafrost and (b) conducted an online survey on inspiration in permafrost science. Our results show an almost 400% increase in publications containing the word permafrost in the title, keywords or abstract over the study period, and a strong increase in climate‐change‐related research in terms of publications and citations. Survey respondents (n = 122) find inspiration not only in scientific journal publications, but to a large extent in books and public outreach materials. We argue that this increase in global‐scope issues (i.e., climate change) complementing core permafrost research has provided new incentives for international collaborations and wider communication efforts. [ABSTRACT FROM AUTHOR]

Rapidly increasing air temperatures will alter permafrost conditions across the Arctic, but variation in soils, vegetation, snow conditions, and their effects on ground thermal regime complicate prediction across spatial and temporal scales. Processes that result in the emergence of new surfaces (lake drainage, channel migration, isostatic uplift, etc.) provide an opportunity to assess the factors influencing permafrost aggradation and terrain evolution under a warming climate. In this study we describe ground temperatures, vegetation, and snow and soil conditions at six drained lake basins (DLBs) that have exposed new terrain in the Tuktoyaktuk Coastlands in the last 20–100 years. We also use one‐dimensional thermal modeling to assess the impact of ecological succession and future climate scenarios on permafrost conditions in historical and future DLBs. Our field observations show that deep snow pack and shallow organic layers at shrub‐dominated DLBs promote increased thaw depth and ground temperatures compared to a sedge‐dominated DLB and two ancient DLB reference sites. Modeling of past and future drainages shows that climate warming projected under RCP 8.5 will reduce rates of permafrost aggradation and thickness, and drive top‐down thaw that could degrade permafrost in shrub‐dominated DLBs by the end of the century. Permafrost at sedge‐dominated sites was more resilient to warming under RCP 8.5, with the onset of top‐down thaw delayed until about 2080. Together, this indicates that the effects of ecological succession on organic soil development and snow drifting will strongly influence the aggradation and resilience of permafrost in DLBs. Our analysis suggests that DLBs and other emergent landscapes will be the first permafrost‐free environments to develop under a warming climate in the continuous permafrost zone. [ABSTRACT FROM AUTHOR]

Active layer probing in northern Sweden, northeast Greenland, and central Svalbard indicates active layer thickening has occurred at Circumpolar Active Layer Monitoring (CALM) sites with long‐term, continuous observations, since the sites were established at these locations in 1978, 1996, and 2000, respectively. The study areas exhibit a reverse latitudinal gradient in average active layer thickness (ALT), which is explained by site geomorphology and climate. Specifically, Svalbard has a more maritime climate and thus the thickest active layer of the study areas (average ALT = 99 cm, 2000–2018). The active layer is thinnest at the northern Sweden sites because it is primarily confined to superficial peat. Interannual variability in ALT is not synchronous across this Nordic Arctic region, but study sites in the same area respond similarly to local meteorology. ALT correlates positively with thawing degree days in Sweden and Greenland, as has been observed in other Arctic regions. However, ALT in Svalbard correlates with freezing degree days, where the maritime Arctic climate results in relatively high and variable winter air temperatures. The difference in annual ALT at adjacent sites is attributed to differences in snow cover and geomorphology. From 2000 to 2018, the average rate of active layer thickening at the Nordic Arctic CALM probing sites was 0.5 cm/yr. The average rate was 1 cm/yr for Nordic Arctic CALM database sites with significant trends, which includes a borehole in addition to probing sites. This range is in line with the circum‐Arctic average of 0.8 cm/yr from 2000 to 2018. [ABSTRACT FROM AUTHOR]

Warming in the Arctic accelerates top‐soil decomposition and deep‐soil permafrost thaw. This may lead to an increase in plant‐available nutrients throughout the active layer soil and near the permafrost thaw front. For nitrogen (N) limited high arctic plants, increased N availability may enhance growth and alter community composition, importantly affecting the ecosystem carbon balance. However, the extent to which plants can take advantage of this newly available N may be constrained by the following three factors: vertical distribution of N within the soil profile, timing of N‐release, and competition with other plants and microorganisms. Therefore, we investigated species‐ and depth‐specific plant N uptake in a high arctic tundra, northeastern Greenland. Using stable isotopic labelling (15N‐NH4+), we simulated autumn N‐release at three depths within the active layer: top (10 cm), mid (45 cm) and deep‐soil near the permafrost thaw front (90 cm). We measured plant species‐specific N uptake immediately after N‐release (autumn) and after 1 year, and assessed depth‐specific microbial N uptake and resource partitioning between above‐ and below‐ground plant parts, microorganisms and soil. We found that high arctic plants actively foraged for N past the peak growing season, notably the graminoid Kobresia myosuroides. While most plant species (Carex rupestris, Dryas octopetala, K. myosuroides) preferred top‐soil N, the shrub Salix arctica also effectively acquired N from deeper soil layers. All plants were able to obtain N from the permafrost thaw front, both in autumn and during the following growing season, demonstrating the importance of permafrost‐released N as a new N source for arctic plants. Finally, microbial N uptake markedly declined with depth, hence, plant access to deep‐soil N pools is a competitive strength. In conclusion, plant species‐specific competitive advantages with respect to both time‐ and depth‐specific N‐release may dictate short‐ and long‐term plant community changes in the Arctic and consequently, larger‐scale climate feedbacks. [ABSTRACT FROM AUTHOR]

Assessments of climate‐change effects on ecosystem processes and services in high‐latitude regions are hindered by a lack of decision‐support tools capable of forecasting possible future landscapes. We describe a collaborative effort to develop and apply the Integrated Ecosystem Model (IEM) for Alaska and northwestern Canada to explore how climate change influences interactions among disturbance regimes, permafrost integrity, hydrology, and vegetation, and how these dynamics in turn influence resource management decisions. This process emphasizes co‐production of knowledge among decision makers, scientists, major funders, partners, and stakeholders. We highlight research findings based on IEM applications in Arctic Alaska, as well as successes and challenges of the co‐production process. The overall framework and lessons from our work with the IEM are relevant to other collaborative efforts outside the Arctic that aim to develop a decision‐support tool or an undertaking of equivalent scope. [ABSTRACT FROM AUTHOR]

A morphological model for estimating ground-ice contents of various landscape units is presented to address the gap between large-scale, general studies and small-scale, site-specific case histories. The model considers different ground-ice types and cryostratigraphic relations between ice bodies within a terrain unit. Input parameters needed for the model are described. Derived variables and algorithms used to determine the quantity of each ground-ice type within a terrain unit are presented. Examples of the application of the model are provided for the Yukon Coastal Plain, northwest Canada. The uncertainties and limiting assumptions of the model are discussed. Copyright © 2017 Natural Resources Canada. Permafrost and Periglacial Processes © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The high Arctic is the world's fasting warming biome, allowing access to sections of previously inaccessible land for resource extraction. Starting in 2011, exploration of one of the Earth's largest undeveloped coal seams was initiated in a relatively pristine, polar desert environment in the Canadian high Arctic. Due to the relative lack of historic anthropogenic disturbance, significant gaps in knowledge exist on how the landscape will be impacted by development., At an abandoned airstrip located near the area of current exploration, we used a disturbance case-control approach to evaluate the long-term ecological consequences of high Arctic infrastructure disturbance to vegetation and sensitive, ice-rich permafrost. We quantified: (i) long-term effects on vegetation diversity, soil nutrients and abiotic ground conditions and (ii) the alteration of the ground surface topography and legacy of subsurface thermal changes., We found that in over 60 years since abandonment, the disturbed landscape has not recovered to initial conditions but instead reflects a disturbance-initiated succession towards a different stable-state community., Microtopography greatly influenced recovery patterns in the landscape. The terrain overlaying buried ice (ice-wedge polygon troughs) was the most sensitive to disturbance and had a different species composition, decreased plot-level species richness, significant increases in vegetation cover and a drastically reduced seasonal fluctuation in subsurface temperatures. In contrast, disturbed polygon tops showed resiliency in vegetation recovery, but still had remarkable increases in depth of seasonal soil thaw (active layer)., Synthesis and applications. Our results indicate that disturbance effects differ depending on microtopographic features, leading to an increased patchiness of the landscape as found elsewhere in the Arctic. Managers who wish to lessen their impact on high Arctic environments should avoid areas of sensitive, ice-rich permafrost, constrain the geographic scale of near-surface ground disturbance, limit vegetation removal where possible and reseed disturbed areas with native species. [ABSTRACT FROM AUTHOR]

1. The polar desert biome of the Canadian high Arctic Archipelago is currently experiencing some of the greatest mean annual air temperature increases on the planet, threatening the stability of ecosystems residing above temperature-sensitive permafrost. 2. Ice wedges are the most widespread form of ground ice, occurring in up to 25% of the world's terrestrial near-surface, and their melting (thermokarst) may catalyse a suite of biotic and ecological changes, facilitating major ecosystem shifts. 3. These unknown ecosystem shifts raise serious questions as to how permafrost stability, vegetation diversity and edaphic conditions will change with a warming high Arctic. Ecosystem and thermokarst processes tend to be examined independently, limiting our understanding of a coupled system whereby the effect of climate change on one will affect the outcome of the other. 4. Using in-depth, comprehensive field observations and a space-for-time approach, we investigate the highly structured landscape that has emerged due to the thermokarst-induced partitioning of microhabitats. We examine differences in vegetation diversity, community composition and soil conditions on the Fosheim Peninsula, Ellesmere Island, Nunavut. We hypothesize that (i) greater ice wedge subsidence results in increased vegetation cover due to elevated soil moisture, thereby decreasing the seasonal depth of thaw and restricting groundwater outflow; (ii) thermokarst processes result in altered vegetation richness, turnover and dispersion, with greater microhabitat diversity at the landscape scale; and (iii) shifts in hydrology and plant community structure alter soil chemistry. 5. We found that the disturbance caused by melting ice wedges catalysed a suite of environmental and biotic effects: topographical changes, a new hydrological balance, significant species richness and turnover changes, and distinct soil chemistries. Thermokarst areas favour a subset of species unique from the polar desert and are characterized by greater species turnover (b-diversity) across the landscape. 6. Synthesis. Our findings suggest that projected increases of thermokarst in the polar desert will lead to the increased partitioning of microhabitats, creating a more heterogeneous high arctic landscape through diverging vegetation communities and edaphic conditions, resulting in a wetland-like biome in the high Arctic that could replace much of the ice-rich polar desert. [ABSTRACT FROM AUTHOR]

We review the predicted changes in extreme events following climate change in flowing waters in arctic and subarctic regions. These regions are characterised by tundra or taiga ecosystems in either erosional or depositional glacial landforms or presently glacierised areas of the Northern Hemisphere., The ecological and geomorphic effects of extreme meteorological and hydrological events, such as episodes of strongly increased precipitation, temperatures and flows, can be exacerbated by altered base conditions. For example, winter temperature variations between frost and thaw will become more frequent at many places because mean temperature during the winter is closer to 0 °C, potentially leading to changes in the production of ice and intensified disturbance of riparian and aquatic habitats during extreme floods. Additionally, thawing of permafrost and glaciers can lead to increased bank erosion because of thaw slump and glacial outburst floods., We discuss the abiotic and biotic effects of these and other extreme events, including heavy precipitation, floods, drought and extreme air or water temperatures, and summarise our findings in a model that aims to stimulate further research in this field. [ABSTRACT FROM AUTHOR]

In the Low Arctic, a warming climate is increasing rates of permafrost degradation and altering vegetation. Disturbance associated with warming permafrost can change microclimate and expose areas of ion-rich mineral substrate for colonization by plants. Consequently, the response of vegetation to warming air temperatures may differ significantly from disturbed to undisturbed tundra. Across a latitudinal air temperature gradient, we tested the hypothesis that the microenvironment in thaw slumps would be warmer and more nutrient rich than undisturbed tundra, resulting in altered plant community composition and increased green alder ( Alnus viridis subsp. fruticosa) growth and reproduction. Our results show increased nutrient availability, soil pH, snow pack, ground temperatures, and active layer thickness in disturbed terrain and suggest that these variables are important drivers of plant community structure. We also found increased productivity, catkin production, and seed viability of green alder at disturbed sites. Altered community composition and enhancement of alder growth and reproduction show that disturbances exert a strong influence on deciduous shrubs that make slumps potential seed sources for undisturbed tundra. Overall, these results indicate that accelerated disturbance regimes have the potential to magnify the effects of warming temperature on vegetation. Consequently, understanding the relative effects of temperature and disturbance on Arctic plant communities is critical to predicting feedbacks between northern ecosystems and global climate change. [ABSTRACT FROM AUTHOR]

Much of the 191.8 Pg C in the upper 1 m of Arctic soil of Arctic soil organic mater is, or is at risk of, being released to the atmosphere as CO2 and/or CH4. Global warming will further alter the rate of emission of these gases to the atmosphere. Here we quantify the effect of major environmental variables affected by global climate change on CH4 fluxes in the Alaskan Arctic. Soil temperature best predicts CH4 fluxes and explained 89% of the variability in CH4 emissions. Water table depth has a nonlinear impact on CH4 efflux. Increasing water table height above the surface retards CH4 efflux. Decreasing water table depth below the surface has a minor effect on CH4 release once an aerobic layer is formed at the surface. In contrast with several other studies, we found that CH4 emissions are not driven by net ecosystem exchange (NEE) and are not limited by labile carbon supply. [ABSTRACT FROM AUTHOR]

This article reports on the environmental and climatic changes and their causes in the Antarctic and Arctic. It discusses that there are continuing increases in surface temperatures, losses of sea ice and tundra, as well as warming of permafrost over areas of the Arctic, while most of the major increase in Antarctic temperatures is on the Antarctic Peninsula linked with sea ice loss in the Bellingshausen-Amundsen Seas sector. The synthesis of observational evidence leads to the conclusion that the Arctic changes of the past several decades are attributable to circulation-driven changes.