Impacts of permafrost degradation on infrastructure

Irrgang A.M., Bendixen M., Farquharson L.M., Baranskaya A.V., Erikson L.H., Gibbs A.E., Ogorodov S.A., Overduin P.P., Lantuit H., Grigoriev M.N., Jones B.M.

Arctic coasts are vulnerable to the effects of climate change, including rising sea levels and the loss of permafrost, sea ice and glaciers. Assessing the influence of anthropogenic warming on Arctic coastal dynamics, however, is challenged by the limited availability of observational, oceanographic and environmental data. Yet, with the majority of permafrost coasts being erosive, coupled with projected intensification of erosion and flooding, understanding these changes is critical. In this Review, we describe the morphological diversity of Arctic coasts, discuss important drivers of coastal change, explain the specific sensitivity of Arctic coasts to climate change and provide an overview of pan-Arctic shoreline change and its multifaceted impacts. Arctic coastal changes impact the human environment by threatening coastal settlements, infrastructure, cultural sites and archaeological remains. Changing sediment fluxes also impact the natural environment through carbon, nutrient and pollutant release on a magnitude that remains difficult to predict. Increasing transdisciplinary and interdisciplinary collaboration efforts will build the foundation for identifying sustainable solutions and adaptation strategies to reduce future risks for those living on, working at and visiting the rapidly changing Arctic coast. Arctic coasts are increasingly affected by erosion and flooding, owing to decreasing sea ice, thawing permafrost and rising sea levels. This Review examines the changes in Arctic coastal morphodynamics and discusses the broader impacts on Arctic systems.

Jones B.M., Grosse G., Farquharson L.M., Roy-Léveillée P., Veremeeva A., Kanevskiy M.Z., Gaglioti B.V., Breen A.L., Parsekian A.D., Ulrich M., Hinkel K.M.

The formation, growth and drainage of lakes in Arctic and boreal lowland permafrost regions influence landscape and ecosystem processes. These lake and drained lake basin (L-DLB) systems occupy >20% of the circumpolar Northern Hemisphere permafrost region and ~50% of the area below 300 m above sea level. Climate change is causing drastic impacts to L-DLB systems, with implications for permafrost dynamics, ecosystem functioning, biogeochemical processes and human livelihoods in lowland permafrost regions. In this Review, we discuss how an increase in the number of lakes as a result of permafrost thaw and an intensifying hydrologic regime are not currently offsetting the land area gained through lake drainage, enhancing the dominance of drained lake basins (DLBs). The contemporary transition from lakes to DLBs decreases hydrologic storage, leads to permafrost aggradation, increases carbon sequestration and diversifies the shifting habitat mosaic in Arctic and boreal regions. However, further warming could inhibit permafrost aggradation in DLBs, disrupting the trajectory of important microtopographic controls on carbon fluxes and ecosystem processes in permafrost-region L-DLB systems. Further research is needed to understand the future dynamics of L-DLB systems to improve Earth system models, permafrost carbon feedback assessments, permafrost hydrology linkages, infrastructure development in permafrost regions and the well-being of northern socio-ecological systems. Lakes and drained lake basins are the most prominent periglacial landforms in northern high-latitude lowland regions, and their dynamics impact permafrost, ecosystem and biogeochemical processes. This Review discusses the influence and consequences of climate change on lake systems.

Heijmans M.M., Magnússon R.Í., Lara M.J., Frost G.V., Myers-Smith I.H., van Huissteden J., Jorgenson M.T., Fedorov A.N., Epstein H.E., Lawrence D.M., Limpens J.

Tundra vegetation productivity and composition are responding rapidly to climatic changes in the Arctic. These changes can, in turn, mitigate or amplify permafrost thaw. In this Review, we synthesize remotely sensed and field-observed vegetation change across the tundra biome, and outline how these shifts could influence permafrost thaw. Permafrost ice content appears to be an important control on local vegetation changes; woody vegetation generally increases in ice-poor uplands, whereas replacement of woody vegetation by (aquatic) graminoids following abrupt permafrost thaw is more frequent in ice-rich Arctic lowlands. These locally observed vegetation changes contribute to regional satellite-observed greening trends, although the interpretation of greening and browning is complicated. Increases in vegetation cover and height generally mitigate permafrost thaw in summer, yet, increase annual soil temperatures through snow-related winter soil warming effects. Strong vegetation–soil feedbacks currently alleviate the consequences of thaw-related disturbances. However, if the increasing scale and frequency of disturbances in a warming Arctic exceeds the capacity for vegetation and permafrost recovery, changes to Arctic ecosystems could be irreversible. To better disentangle vegetation–soil–permafrost interactions, ecological field studies remain crucial, but require better integration with geophysical assessments. Greening and vegetation community shifts have been observed across Arctic environments. This Review examines these changes and their impact on underlying permafrost.

Miner K.R., Turetsky M.R., Malina E., Bartsch A., Tamminen J., McGuire A.D., Fix A., Sweeney C., Elder C.D., Miller C.E.

Arctic permafrost stores nearly 1,700 billion metric tons of frozen and thawing carbon. Anthropogenic warming threatens to release an unknown quantity of this carbon to the atmosphere, influencing the climate in processes collectively known as the permafrost carbon feedback. In this Review, we discuss advances in tracking permafrost carbon dynamics, including mechanisms of abrupt thaw, instrumental observations of carbon release and model predictions of the permafrost carbon feedback. Abrupt thaw and thermokarst could emit a substantial amount of carbon to the atmosphere rapidly (days to years), mobilizing the deep legacy carbon sequestered in Yedoma. Carbon dioxide emissions are proportionally larger than other greenhouse gas emissions in the Arctic, but expansion of anoxic conditions within thawed permafrost and soils stands to increase the proportion of future methane emissions. Increasingly frequent wildfires in the Arctic will also lead to a notable but unpredictable carbon flux. More detailed monitoring though in situ, airborne and satellite observations will provide a deeper understanding of the Arctic’s future role as a carbon source or sink, and the subsequent impact on the Earth system. Large stores of carbon could be released to the atmosphere from Arctic warming, driving permafrost thaw. This Review examines the processes that impact Arctic permafrost carbon emissions, how they might change in the future and ways to monitor and predict these changes.

Smith S.L., O’Neill H.B., Isaksen K., Noetzli J., Romanovsky V.E.

Permafrost temperatures have increased in polar and high-elevation regions, affecting the climate system and the integrity of natural and built environments. In this Review, we outline changes in the thermal state of permafrost, focusing on permafrost temperatures and active-layer thickness. Increases in permafrost temperature vary spatially owing to interactions between climate, vegetation, snow cover, organic-layer thickness and ground ice content. In warmer permafrost (temperatures close to 0 °C), rates of warming are typically less than 0.3 °C per decade, as observed in sub-Arctic regions. In colder permafrost (temperatures less than −2 °C), by contrast, warming of up to about 1 °C per decade is apparent, as in the high-latitude Arctic. Increased active-layer thicknesses have also been observed since the 1990s in some regions, including a change of 0.4 m in the Russian Arctic. Simulations unanimously indicate that warming and thawing of permafrost will continue in response to climate change and potentially accelerate, but there is substantial variation in the magnitude and timing of predicted changes between different models and scenarios. A greater understanding of longer-term interactions between permafrost, climate, vegetation and snow cover, as well as improved model representation of subsurface conditions including ground ice, will further reduce uncertainty regarding the thermal state of permafrost and its future response. Permafrost thaw is directly governed by the thermal characteristics of the frozen ground. This Review outlines the status of and mechanisms influencing the thermal state of permafrost, revealing widespread increases in permafrost temperatures and active-layer thicknesses.

Jungsberg L., Herslund L.B., Nilsson K., Wang S., Tomaškovičová S., Madsen K., Scheer J., Ingeman-Nielsen T.

Global warming has reduced the extent of permafrost, increased permafrost temperatures, and deepened the active layer across the Arctic. Permafrost degradation has detrimental effects on infrastruc...

Ni J., Wu T., Zhu X., Wu X., Pang Q., Zou D., Chen J., Li R., Hu G., Du Y., Hao J., Li X., Qiao Y.

Climate warming could exacerbate the occurrence of thaw settlement hazard in the permafrost regions of the Qinghai-Tibet Plateau (QTP), which would threaten the stability of engineering infrastructure in cold regions. The risk associated with permafrost settlement, valuable for the regional sustainable development, remains poorly assessed or understood on the QTP. In this study, three common Geo-hazard indices were used to assess the settlement risks in the permafrost regions of the QTP, including the settlement index, the risk zonation index, and the allowable bearing capacity index. However, large spatial differences existed in simulating the risk maps by using the abovementioned Geo-hazard indices. Hence, we developed a combined index ( I c ) by integrating the three indices to reduce the uncertainty of the simulations. The results indicated that the ground ice is a critical factor for assessing the settlement risk in permafrost regions. We also applied the I c to assess the settlement risk along the Qinghai-Tibet Railway (QTR). The proportion of low-risk area along the QTR would be the highest (45.38%) for the future periods 2061–2080 under Representative Concentration Pathway 4.5. The medium-risk area combined with the high-risk area would be accounted for more than 40%, which were located at the boundary of the present permafrost regions. Therefore, the corresponding adaptation measures should be taken to reduce the potential economic losses caused by the high-risk regions to the infrastructure. Overall, the results would present valuable references for engineering design, construction and maintenance, and provide insights for early warning and prevention of permafrost thaw settlement hazard on the QTP. • A combined index is proposed to predict the permafrost settlement on the QTP. • The ground ice is a critical factor for the settlement of permafrost. • More than 40% of the QTP permafrost is in the medium-high settlement risk area.

Schneider von Deimling T., Lee H., Ingeman-Nielsen T., Westermann S., Romanovsky V., Lamoureux S., Walker D.A., Chadburn S., Trochim E., Cai L., Nitzbon J., Jacobi S., Langer M.

Abstract. Infrastructure built on perennially frozen ice-rich ground relies heavily on thermally stable subsurface conditions. Climate-warming-induced deepening of ground thaw puts such infrastructure at risk of failure. For better assessing the risk of large-scale future damage to Arctic infrastructure, improved strategies for model-based approaches are urgently needed. We used the laterally coupled 1D heat conduction model CryoGrid3 to simulate permafrost degradation affected by linear infrastructure. We present a case study of a gravel road built on continuous permafrost (Dalton highway, Alaska) and forced our model under historical and strong future warming conditions (following the RCP8.5 scenario). As expected, the presence of a gravel road in the model leads to higher net heat flux entering the ground compared to a reference run without infrastructure and thus a higher rate of thaw. Further, our results suggest that road failure is likely a consequence of lateral destabilisation due to talik formation in the ground beside the road rather than a direct consequence of a top-down thawing and deepening of the active layer below the road centre. In line with previous studies, we identify enhanced snow accumulation and ponding (both a consequence of infrastructure presence) as key factors for increased soil temperatures and road degradation. Using differing horizontal model resolutions we show that it is possible to capture these key factors and their impact on thawing dynamics with a low number of lateral model units, underlining the potential of our model approach for use in pan-Arctic risk assessments. Our results suggest a general two-phase behaviour of permafrost degradation: an initial phase of slow and gradual thaw, followed by a strong increase in thawing rates after the exceedance of a critical ground warming. The timing of this transition and the magnitude of thaw rate acceleration differ strongly between undisturbed tundra and infrastructure-affected permafrost ground. Our model results suggest that current model-based approaches which do not explicitly take into account infrastructure in their designs are likely to strongly underestimate the timing of future Arctic infrastructure failure. By using a laterally coupled 1D model to simulate linear infrastructure, we infer results in line with outcomes from more complex 2D and 3D models, but our model's computational efficiency allows us to account for long-term climate change impacts on infrastructure from permafrost degradation. Our model simulations underline that it is crucial to consider climate warming when planning and constructing infrastructure on permafrost as a transition from a stable to a highly unstable state can well occur within the service lifetime (about 30 years) of such a construction. Such a transition can even be triggered in the coming decade by climate change for infrastructure built on high northern latitude continuous permafrost that displays cold and relatively stable conditions today.

Gibson C.M., Brinkman T., Cold H., Brown D., Turetsky M.

Abstract Understanding the causes and consequences of environmental change is one of the key challenges facing researchers today as both types of information are required for decision making and adaptation planning. This need is particularly poignant in high latitude regions where permafrost thaw is causing widespread changes to local environments and the land-users who must adapt to changing conditions to sustain their livelihoods. The inextricable link between humans and their environments is recognized through socio-ecological systems research, yet many of these approaches employ top-down solutions that can lead to local irrelevance and create tensions amongst groups. We present and employ a framework for the use both of scientific and community-based knowledge sources that provides an enriched and thematic understanding of how permafrost thaw will affect northern land-users. Using geospatial modeling of permafrost vulnerability with community-based data from nine rural communities in Alaska, we show that permafrost thaw is a major driver of hazards for land-users and accounts for one-third to half of the hazards reported by community participants. This study develops an integrated permafrost-land-user system, providing a framework for thematic inquiry for future studies that will add value to large-scale institutional efforts and locally relevant observations of environmental change.

Garnello A., Marchenko S., Nicolsky D., Romanovsky V., Ledman J., Celis G., Schädel C., Luo Y., Schuur E.A.

Northern circumpolar permafrost thaw affects global carbon cycling, as large amounts of stored soil carbon becomes accessible to microbial breakdown under a warming climate. The magnitude of carbon release is linked to the extent of permafrost thaw, which is locally variable and controlled by soil thermodynamics. Soil thermodynamic properties, such as thermal diffusivity, govern the reactivity of the soil-atmosphere thermal gradient, and are controlled by soil composition and drainage. In order to project permafrost thaw for an Alaskan tundra experimental site, we used seven years of site data to calibrate a soil thermodynamic model using a data assimilation technique. The model reproduced seasonal and interannual temperature dynamics for shallow (5–40 cm) and deep soil layers (2–4 m), and simulations of seasonal thaw depth closely matched observed data. The model was then used to project permafrost thaw at the site to the year 2100 using climate forcing data for three future climate scenarios (RCP 4.5, 6.0, and 8.5). Minimal permafrost thawing occurred until mean annual air temperatures rose above the freezing point, after which we measured over a 1 m increase in thaw depth for every 1 °C rise in mean annual air temperature. Under no projected warming scenario was permafrost remaining in the upper 3 m of soil by 2100. We demonstrated an effective data assimilation method that optimizes parameterization of a soil thermodynamic model. The sensitivity of local permafrost to climate warming illustrates the vulnerability of sub-Arctic tundra ecosystems to significant and rapid soil thawing.

Kuznetsov G.V., Ponomarev K.O., Feoktistov D.V., Orlova E.G., Lyulin Y.V., Ouerdane H.

The observed influence of ambient air temperature on ground temperature in the Far North is an urgent problem as excessive warming of the ground may cause permafrost thawing and structural instability of the built environment. A promising solution is to use thermosyphon-based cooling systems for thermal stabilization of the ground surrounding the piles or other supporting elements of special constructions in the Far North. In this work, we experimentally studied the influence of air and ground temperatures and heating surface temperature that simulates the operation of heat-loaded equipment on the mechanisms of the condensate formation in a thermosyphon. We determined the effect of the thermosyphon operation on the change in ground temperature in the Far North and found the possibility of operation of the thermosyphon-based cooling system at air temperatures in the range of 4–10 °C. In addition, it was found that with an increase in the ambient air temperature from 4 to 10 °C, the ground temperature increased by 5–5.5 °C without the thermosyphon and by 3.1–4 °C with the thermosyphon. The operation of the thermosyphon in the ground layer made possible a two-fold reduction at least of its temperature, not only in close vicinity of the evaporation section, but also at a depth exceeding the height of the thermosyphon evaporation section. We also showed that there are two condensation modes (drop-streak and film-streak) when the heat flux supplied to the lower cover was between 0.7 and 5.1 kW/m2, and the condensation section was cooled due to natural convection.

Streletskiy D.

Permafrost degradation presents serious consequences, from local changes in topographic and hydrologic conditions to impacts on the infrastructure, food security and sustainability of northern communities, and global-scale effects on the climate system. Hazards associated with permafrost degradation are exacerbated in areas of human activities. Climatic changes since the early 1980s have resulted in a decrease of permafrost extent, an increase of permafrost temperature, and thickening of the active layer in numerous locations across the Arctic, the Antarctic, and high-mountain environments. Small subsistence-oriented communities and large industrial centers on permafrost will need to continue to develop in situ adaptive capacity to face environmental changes that are anticipated over the next 50 years. Permafrost degradation can have severe socioeconomic consequences, as most existing infrastructure will require expensive engineering solutions to maintain its economic function.

Deline P., Gruber S., Amann F., Bodin X., Delaloye R., Failletaz J., Fischer L., Geertsema M., Giardino M., Hasler A., Kirkbride M., Krautblatter M., Magnin F., McColl S., Ravanel L., et. al.

The present time is a significant stage in the adjustment of mountain slopes to climate change and specifically atmospheric warming. This review examines the state of understanding of the responses of mid-latitude alpine landscapes to recent cryospheric change and summarizes the variety and complexity of documented landscape responses involving glaciers, moraines, rock and debris slopes, and rock glaciers. These indicate how a common general forcing translates into varied site-specific slope responses according to material structures and properties, thermal and hydrological environments, process rates, and prior slope histories. Warming of permafrost in rock and debris slopes has demonstrably increased instability, manifest as rock glacier acceleration, rockfalls, debris flows, and related phenomena. Changes in glacier geometry influence stress fields in rock and debris slopes, and some failures appear to be accelerating toward catastrophic failure. Several sites now require expensive monitoring and modeling to design effective risk-reduction strategies, especially where new lakes form and multiply hazard potential, and new activities and infrastructure are developed.

Kong X., Doré G., Calmels F., Lemieux C.

Permafrost degradation under transportation infrastructure often results in thaw settlement due to thawing of the ice-rich subgrade. Climate change is associated with permafrost-related engineering problems. Air convection embankments (ACE) have been proven to be an effective method to prevent permafrost thawing, in response to climate change. Poorly-graded aggregates are used to facilitate the air flow in an ACE, especially during winter when the air density gradient is unstable. A large-scale ACE test section was constructed along the Alaska Highway in 2008 at Beaver Creek, Yukon, Canada, to investigate the heat extraction capacity of ACEs. Boreholes under the toe, the side slope and the centerline were drilled and instrumented. Temperature data collected at this site were used to investigate the thermal performance of the ACE and to calibrate a 2D thermal model that was developed based on the Beaver Creek experimental site. Specific site characteristics, such as air temperature, foundation soil properties and embankment dimensions, were measured and used as input parameters to improve the accuracy of the 2D model developed. A relatively new approach based on heat balance at the embankment-soil interface has been proposed to investigate the heat extraction capacity of ACEs. After satisfactory calibration of the model at the Beaver Creek site, an engineering design chart has been developed and is proposed to assess the heat balance at the embankment-soil interface for different embankment thicknesses and site conditions. • The full-scale ACE was built on the Alaska Highway at Beaver Creek, Yukon in 2008 and its thermal effectiveness was analyzed. • The heat balance approach was proposed to quantify the heat extraction capacity of the ACE. A 2D thermal model was calibrated to the measured data. • The engineering design chart was developed to determine the ACE thickness required for the long-term thermal stability of the embankment built on thaw-sensitive permafrost.

Mekonnen Z.A., Riley W.J., Grant R.F., Romanovsky V.E.

Abstract Surface energy budgets of high-latitude permafrost systems are poorly represented in Earth system models (ESMs), yet permafrost is rapidly degrading and these dynamics are critical to future carbon-climate feedback predictions. A potentially important factor in permafrost degradation neglected so far by ESMs is heat transfer from precipitation, although increases in soil temperature and thaw depth have been observed following increases in precipitation. Using observations and a mechanistic ecosystem model, we show here that increases in precipitation hasten active layer development beyond that caused by surface air warming across the North Slope of Alaska (NSA) under recent and 21st century climate (RCP8.5). Modeled active layer depth (ALD) in simulations that allow precipitation heat transfer agreed very well with observations from 28 Circumpolar Active Layer Monitoring sites (R2 = 0.63; RMSE = 10 cm). Simulations that ignored precipitation heat transfer resulted in lower spatially-averaged soil temperatures and a 39 cm shallower ALD by 2100 across the NSA. The results from our sensitivity analysis show that projected increases in 21st century precipitation deepen the active layer by enhancing precipitation heat transfer and ground thermal conductivity, suggesting that precipitation is as important an environmental control on permafrost degradation as surface air temperature. We conclude that ESMs that do not account for precipitation heat transfer likely underestimate ALD rates of change, and thus likely predict biased ecosystem responses.

Xu C., Zhang Z., Zhao Y., Jin D., Yu Q., Meng X.

Liu S., Zhao L., Wang L., Liu L., Zou D., Hu G., Sun Z., Zhang Y., Chen W., Wang X., Wang M., Zhou H., Qiao Y.

Ge J., Sun H., Liu R., Huang Z., Tian B., Liu L., Zheng Z.

Yang S., Zhang M., Pei W., Wan X., Lu J., Yan Z., Bai R., Bi J.

Yang J., Zhang R., Li X., Wang X., Dyck M., Wang L., Wu Q., He H.

Fan C., Mu C., Liu L., Zhang T., Jia S., Wang S., Sun W., Zhao Z.

Lu X., Yu J., Li J., Yu Y., Sun L., Li M.

Cao Y., Li G., Ma W., Cui Y., Wang H., Gao K., Chen P., Alexander F., Chen D., Bai L., Su A.

Abweny M.A., Abdel-Jawad A., Xiao S.

Wei H., Yao Z., Wang X., Song Z.

Manos E., Witharana C., Liljedahl A.K.

Zhang Z., Zhang D., Yao W., Wu Q., Lan X., Li M.

ABSTRACTThe seasonal freezing layer is an important indicator of frozen ground's responses to climatic warming and environmental changes. In Northeast China, the permafrost and taliks interweave with major spatial discontinuity and variability. The spatiotemporal variability of the seasonal freezing layer and the contribution of environmental factors to these changes are not fully understood. Based on 51 ground temperature monitoring sites in Northeast China from 2005 to 2020, the maximum depth of the seasonal freezing (MDSF) was calculated, and the environment and climate‐driven changes in the MDSF were analysed by classification and the regression trees method. The MDSF showed an overall decrease in the region. With local thickening, the MDSF varied between 1.2 and 3.1 m at a rate of −4.34 to 4.80 cm/year. Air temperature warming is the main driver (34%) of regional MDSF changes. Vegetation, rainfall and snow play a prominent role in the Da and Xiao Xing'anling region in Northeast China. The impact of other environmental factors locally outweighs the air temperature. The findings highlighted the importance of environmental factors beyond air temperature in influencing changes in the active layer, emphasising their contribution to spatial and temporal variations.

Cordier M., Vasilevskaya A., Jungsberg L., Vanderlinden J., Ramage J., Lantuit H.

Bai L., Li J., Liu T., Jiang Z., Mao D.

AbstractFrozen soil resistivity exhibits high sensitivity to temperature variations and ice‐water distribution. The conversion of soil water content (SWC) and resistivity based on petrophysical relationships enables the characterization of spatial distribution and changes in freezing and thawing states. Monitoring ground resistivity is essential for understanding frozen soil structure and evaluating climate change and ecosystems. The previous studies demonstrate that estimating soil resistivity below zero degrees based on the empirical model has significant errors. This work proposes a capillary bundle fractal model for frozen soil resistivity estimation based on SWC hydrologic parameters. The fractal theory describes the geoelectrical features of frozen porous media through the variable pore geometry and representative elementary volume. The sensitivity analysis discusses the potential relationships between pore parameters, conductance components, and fractal geometric parameters within frozen soil resistivity and reconstructs the hysteresis separation of freeze‐thaw processes. The field test application in the seasonal freeze‐thaw monitoring site demonstrates that the estimated resistivity and experimental samples are consistent with the field monitoring resistivity data. By combining unified conceptual assumptions, we established the connection between electrical permeability and thermal conductivity, offering a basis for exploring coupled hydro‐thermal mechanisms in frozen soil. The proposed model accurately estimates the variations in seasonal frozen resistivity, providing a reliable reference for quantitatively analyzing the mechanisms of freeze‐thaw processes.

Kim T., Villarini G., Prein A.F., Done J.M., Johnson D.R., Wang C.