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Die sowjetische Politik zur Besiedelung des hohen Nordens hat in den 1960er bis 1980er Jahren zu einer massiven Migrationsbewegung dorthin geführt, die in der sowjetischen Arktis ein massives Bevölkerungswachstum und ein atemberaubendes Tempo der Urbanisierung zur Folge hatte. Mehrstöckige Gebäude, Straßennetze und andere Infrastruktur wurden errichtet, die die unberührte Tundra in anthropogene und urbane Landschaften verwandelten. Die – ungeachtet aller Kosten und Schwierigkeiten – starke Konzentration der Sowjetunion auf die Entwicklung der arktischen Gebiete hat dem modernen Russland ein problematisches Erbe hinterlassen. Eines der verbreiteten Probleme, das von vielen urbanen Gemeinschaften aus der Sowjetzeit geteilt wird, ist der fragile Zustand der auf Permafrostböden errichteten Infrastruktur. Dieser Beitrag bietet einen kurzen Überblick über die Herausforderungen, die im Zusammenhang mit urbaner Entwicklung in Permafrost-Gegenden entstehen. Das soll dem Versuch dienen, die Gründe für gegenwärtige Infrastrukturprobleme in vielen Siedlungen des russischen Nordens zu ermitteln.

Climate change has adverse impacts on Arctic natural ecosystems and threatens northern communities by disrupting subsistence practices, limiting accessibility, and putting built infrastructure at risk. In this paper, we analyze spatial patterns of permafrost degradation and associated risks to built infrastructure due to loss of bearing capacity and thaw subsidence in permafrost regions of the Arctic. Using a subset of three Coupled Model Intercomparison Project 6 models under SSP245 and 585 scenarios we estimated changes in permafrost bearing capacity and ground subsidence between two reference decades: 2015–2024 and 2055–2064. Using publicly available infrastructure databases we identified roads, railways, airport runways, and buildings at risk of permafrost degradation and estimated country-specific costs associated with damage to infrastructure. The results show that under the SSP245 scenario 29% of roads, 23% of railroads, and 11% of buildings will be affected by permafrost degradation, costing $182 billion to the Arctic states by mid-century. Under the SSP585 scenario, 44% of roads, 34% of railroads, and 17% of buildings will be affected with estimated cost of $276 billion, with airport runways adding an additional $0.5 billion. Russia is expected to have the highest burden of costs, ranging from $115 to $169 billion depending on the scenario. Limiting global greenhouse gas emissions has the potential to significantly decrease the costs of projected damages in Arctic countries, especially in Russia. The approach presented in this study underscores the substantial impacts of climate change on infrastructure and can assist to develop adaptation and mitigation strategies in Arctic states.

The Arctic is experiencing pronounced climatic and environmental changes. These changes pose a risk to infrastructure, impacting the accessibility and development of remote locations and ad...

Long-term (1982–1995) observations of the ground thermal regime of a drained thaw-lake basin in the Pechora Lowlands of the Russian European north revealed a high spatial and temporal variability in the ground temperature response to artificial drainage. The thermal response was controlled by the atmospheric climate and by evolution of the landsurface following drainage. Observed changes in permafrost conditions were related to three climatic subperiods identified from air and ground temperature trends. The first (1982–1984) was characterized by gradual ground cooling associated with partial formation of permafrost patches under the initial stage of formation of marshy meadows. The second (1985–1987) involved strong ground cooling, resulting in the formation of a subsurface permafrost layer beneath most of the basin. The third (1988–1995) was marked by a gradual increase in annual mean ground temperature, promoting partial permafrost degradation under marshy meadows and willow stands. Initially, newly aggraded permafrost remained under peat mounds and tundra meadows. The spatial pattern of permafrost change can be attributed to heterogeneous landsurface evolution and variable snow thickness. Four distinct ground temperature regimes are distinguished: (i) thawed ground, (ii) deep permafrost, (iii) unstable permafrost and (iv) stable permafrost.

In popular imagination, the Arctic is frequently perceived as a vast, desolate, and undeveloped region with predominantly indigenous population and isolated clusters of resource extraction and mili...

Increasing atmospheric temperatures over the last 30 years has prompted land cover change in sensitive Arctic environments and exacerbated change in large urban-industrial centers on permaf...

The city of Norilsk represents an unprecedented case of massive construction in the permafrost regions of the Arctic. Norilsk’s urban expansion can be attributed to the development of engineering practices that maintained the thermal stability of permafrost. However, complex interactions between the urban landscape and permafrost have resulted in permafrost warming and degradation. Negative cryogenic processes started to manifest themselves 10–15 years after the initial development and have intensified with time. Problems were further exacerbated by the poor quality of construction, improper operation of the city infrastructure, socio-economic transitions, and unanticipated climatic changes. The warming and degradation of permafrost have contributed to a widespread deformation of structures in Norilsk. In this paper, we discuss the role of permafrost in the urban development of Norilsk, specific human- and climate-induced geotechnical problems related to permafrost, and innovative economically via...

Ice cellars are a natural form of refrigeration constructed within permafrost. They are traditionally employed by indigenous Arctic peoples to store harvested wildlife. Recent reports from Alaska i...

One of the most significant climate change impacts on arctic urban landscapes is the warming and degradation of permafrost, which negatively affects the structural integrity of infrastructure. We estimate potential changes in stability of Russian urban infrastructure built on permafrost in response to the projected climatic changes provided by six preselected General Circulation Models (GCMs) participated in the most recent Climate Model Inter-comparison Project (CMIP5). The analysis was conducted for the entire extent of the Russian permafrost-affected area. According to our analysis a significant (at least 25%) climate-induced reduction in the urban infrastructure stability throughout the Russian permafrost region should be expected by the mid-21st century. However, the high uncertainty, resulting from the GCM-produced climate projections, prohibits definitive conclusion about the rate and magnitude of potential climate impacts on permafrost infrastructure. Results presented in this paper can serve as guidelines for developing adequate adaptation and mitigation strategy for Russian northern cities.

In some regions underlain by ice-rich permafrost, a consistent, long-term increase in ALT under changing climatic conditions is not supported by observations. The apparent lack of ALT may be attributed to soil consolidation from thawing of the uppermost ice-rich permafrost and subsidence of the ground surface. Four plots established in 1962 at Barrow, Alaska, were re-instrumented in 2003 and surveyed annually using differential GPS technology, accompanied by active-layer probing. Elevation change from 1962 to 2003 was within the interannual variability of the 2003–15 period, indicating net stability in the area. Over the 2003–15 period, however, all four plots experienced subsidence trends of 0.4–1.0 cm/year, resulting in a net elevation change of 8–15 cm. Warmer winters and increased snow depth during this period decreased the potential for frost heave. Warmer summers resulted in thaw penetration into the ice-rich transient layer and ice wedges, leading to the net subsidence in recent years. Copyright © 2016 John Wiley & Sons, Ltd.

This article traces the governance path affecting the boom-bust cycle in the Russian Arctic city of Vorkuta as a case study examining the role of institutional capacity and informality in mitigating the consequences of the cycle. The analysis examines the usefulness of various tools, including planning, policy, and informality. It also investigates the role of different actors, including the national and local components of the state and private corporations. The conclusion provides a typology of formal and informal land use tools. Soviet planners failed to foresee the bust and did not make provisions for it. Subsequently, the failure of national and local state policies to provide full solutions, combined with the absence of sufficient investment from private sector corporations, opened the door to a broad-ranging informality that encompasses policy-making, individual entrepreneurship, and associated conceptions of individual actions in society. The Soviet/Russian experience differs from that of other countries because in the last 100 years it has run the full gamut from a planned economy to unbridled capitalism. In cross-national comparison, it demonstrates the potential value of informal practices in situations where there is weak formal institutional capacity.

During the past several decades, the Earth system has changed significantly, especially across NorthernEurasia. Changes in the socio-economic conditions of the larger countries in the region have also resulted ina variety of regional environmental changes that can have global consequences. The Northern Eurasia FutureInitiative (NEFI) has been designed as an essential continuation of the Northern Eurasia Earth SciencePartnership Initiative (NEESPI), which was launched in 2004. NEESPI sought to elucidate all aspects of ongoingenvironmental change, to inform societies and, thus, to better prepare societies for future developments. Akey principle of NEFI is that these developments must now be secured through science-based strategies codesignedwith regional decision-makers to lead their societies to prosperity in the face of environmental andinstitutional challenges. NEESPI scientific research, data, and models have created a solid knowledge base tosupport the NEFI program. This paper presents the NEFI research vision consensus based on that knowledge.It provides the reader with samples of recent accomplishments in regional studies and formulates new NEFIscience questions. To address these questions, nine research foci are identified and their selections are brieflyjustified. These foci include warming of the Arctic; changing frequency, pattern, and intensity of extreme andinclement environmental conditions; retreat of the cryosphere; changes in terrestrial water cycles; changes inthe biosphere; pressures on land use; changes in infrastructure; societal actions in response to environmentalchange; and quantification of Northern Eurasia’s role in the global Earth system. Powerful feedbacks betweenthe Earth and human systems in Northern Eurasia (e.g., mega-fires, droughts, depletion of the cryosphereessential for water supply, retreat of sea ice) result from past and current human activities (e.g., large-scalewater withdrawals, land use, and governance change) and potentially restrict or provide new opportunities forfuture human activities. Therefore, we propose that integrated assessment models are needed as the finalstage of global change assessment. The overarching goal of this NEFI modeling effort will enable evaluationof economic decisions in response to changing environmental conditions and justification of mitigation andadaptation efforts.

Russian regions containing permafrost play an important role in the Russian economy, containing vast reserves of natural resources and hosting large-scale infrastructure to facilitate these resources' exploitation. Rapidly changing climatic conditions are a major concern for the future economic development of these regions. This study examines the extent to which infrastructure and housing are affected by permafrost in Russia and estimates the associated value of these assets. An ensemble of climate projections is used as a forcing to a permafrost-geotechnical model, in order to estimate the cost of buildings and infrastructure affected by permafrost degradation by mid-21st century under RCP 8.5 scenario. The total value of fixed assets on permafrost was estimated at 248.6 bln USD. Projected climatic changes will affect 20% of structures and 19% of infrastructure assets, costing 16.7 bln USD and 67.7 bln USD respectively to mitigate. The total cost of residential real estate on permafrost was estimated at 52.6 bln USD, with 54% buildings affected by significant permafrost degradation by the mid-21st century. The paper discusses the variability in climate-change projections and the ability of Russia's administrative regions containing permafrost to cope with projected climate-change impacts. The study can be used in land use planning and to promote the development of adaptation and mitigation strategies for addressing the climate-change impacts of permafrost degradation on infrastructure and housing.

[1] Observations in undisturbed terrain within some regions of the Arctic reveal limited correlation between increasing air temperature and the thickness of the seasonally thawed layer above ice-rich permafrost. Here we describe landscape-scale, thaw-induced subsidence lacking the topographic contrasts associated with thermokarst terrain. A high-resolution, 11 year record of temperature and vertical movement at the ground surface from contrasting physiographic regions of northern Alaska, obtained with differential global positioning systems technology, indicates that thaw of an ice-rich layer at the top of permafrost has produced decimeter-scale subsidence extending over the entire landscapes. Without specialized observation techniques the subsidence is not apparent to observers at the surface. This “isotropic thaw subsidence” explains the apparent stability of active layer thickness records from some landscapes of northern Alaska, despite warming near-surface air temperatures. Integrated over extensive regions, it may be responsible for thawing large volumes of carbon-rich substrate and could have negative impacts on infrastructure.

IntroductionRussia’s natural resource-rich andlightly populated Arctic region boastsmore than its share of the country’s GDP,and climate change may determine thearea’s future economic expansion andurban settlement patterns. Smith (2010,157-163) predicts a “New North” in whichclimate change will ameliorate the hostilenatural environment, open ice-bound Arc-tic shipping lanes and attract new inhabit-ants. However, Russia’s turbulent freemarket transition has already created a“New North” as the new capitalistic busi-ness model and high costs of residencyhave transformed the economic opportuni-ties and migration and settlement patternsin this remote region.This research compares the migrationmanagement strategies of two Siberiancities, Igarka and Norilsk, as theyattempt to achieve their economic andsocial sustainability in the market context.Located above the Arctic Circle, Igarkaand Norilsk have both experienced popu-lation decline since 1991 (Figure 1). Theyare among the scores of Arctic settle-ments established through Soviet centralplanning that are attempting to reinventthemselves in order to survive. The stateand the region’s powerful naturalresource companies have abandoned theirtraditional paternal role in these settle-ments. Industries have shuttered ordownsized, shedding jobs and social ben-efits and forcing some Arctic residents tomove to larger towns or flee the regionentirely, although other residents lack themeans to do so. As a result, in the farnorth and other peripheral regions demo-graphic changes are distributed unevenly,as some cities, towns, and administrativedistricts shrink while other areas main-tain steady populations or even grow(Heleniak 2009a).According to the Russian PresidentialAdvisor for Climate, Alexander Bedritsky,the Arctic region is inhabited by 1.5% ofthe population although it is responsiblefor about 11% of the country’s GDP,Figure 1. Study sites Norilsk and Igarka are located within the Arctic Circle, along the Yenisei River. The river is an important conduit for theregion’s people and goods. (Cartography by Dmitry Streletskiy)Fall 2012 FOCUS on Geography 77

Increases in air temperature have occurred in most parts of the Arctic in recent decades. Corresponding changes in permafrost and the active layer have resulted in decreases in ground-bearing capacity, which may not have been anticipated at the time of construction in permafrost regions. Permafrost model was coupled with empirically derived solutions adopted from Soviet and Russian construction standards and regulations to estimate the bearing capacity of foundations under rapidly changing climatic conditions, in a variety of geographic and geologic settings. Changes in bearing capacity over the last 40 years were computed for large population and industrial centers within different physiographic and climatic conditions of the Russian Arctic. The largest decreases were found in city of Nadym, where the bearing capacity has decreased by more than 40%. A smaller, but considerable decrease of approximately 20% was estimated for Yakutsk and Salekhard. Spatial model results at a regional scale depict ...

The active layer plays an important role in the functioning of environmental ecosystems and affects many human activities in the polar regions. Regional assessments and predictions of this parameter are critical for many physical and social applications. Large heterogeneity in near-surface permafrost characteristics, including the active layer, even over small distances, creates serious constraints to their evaluation across large geographic extents. Discrepancies between modeled climatic fields add to the uncertainties associated with predicting active-layer thickness (ALT) at regional scales. This study uses a stochastic approach, in combination with an equilibrium permafrost model, to map the geographic distribution of ALT and near-surface permafrost temperature on the North Slope of Alaska. GIS techniques are used to determine the spatial variabilityof ecosystem factors controlling the ground thermal regime within each grid cell of the permafrost model. To incorporate the uncertainty associated with t...

Arctic settlements built on permafrostface rather unique set of geotechnical challenges. On urbanized areas, technogenic transformation of natural landscapes due toconstruction of various types of infrastructure leads to changes in heat exchange in permafrost-atmosphere system. The spatial distribution and intensity of dangerous cryogenic processes in urbanized areas is substantially different from natural background settings found prior to construction. Climate change, especially pronounced in the Arctic, exacerbated these changes. Combination of technogenic pressure and climate change resulted in potentially hazardous situation in respect to operational safety of the buildings and structures built on permafrost. This paper is focused on geotechnical safety issues faced by the Arctic urban centers built on permafrost. Common types of technogenic impacts characteristic for urban settlements wereevaluated based on field observations and modeling techniques. The basic principles of development of deformations are discussed in respect to changing permafrost conditions and operational mode of the structures built on permafrost.

A significant portion of the Tibetan Plateau is underlain by permafrost, and is highly sensitive to climate change. Observational data from recent Chinese investigations on permafrost degradation and its environmental effects in the Tibetan region indicate that a large portion of the Tibetan Plateau has experienced significant warming since the mid-1950s. The air temperature increase is most significant in the central, eastern, and northwestern parts of the Plateau. The warming trend in the cold season was greater than that in the warm season. The duration of seasonal ground freezing has shortened due to the air temperature increase in winter. Numerical simulations indicate that air temperature on the Plateau will continue to increase in the 21st century. Significant warming has resulted in extensive degradation of permafrost. Over the last 30 years, a 25 m increase in the lower altitudinal occurrences of permafrost has taken place in the north. In the south the increase is 50–80 m over the past 20 years. Active-layer thickness and mean annual ground temperature have increased by 0.15–0.50 m during 1996–2001 and by 0.1–0.5 °C during the last 30 years on the Tibetan Plateau, respectively. Widespread permafrost degradation has already caused environmental deterioration. Extensive desertification processes are apparent in the eastern and western portions of the Tibetan Plateau, with the area occupied by desert increasing annually by about 1.8%. With rapid retreat and thinning of permafrost, large carbon pools sequestered in permafrost could be released to increase net sources of atmospheric carbon, creating a positive feedback and accelerated warming. Damage to human infrastructure is also caused by frost heave, thaw settlement, and thaw slumping in the permafrost-affected region. The impact of permafrost degradation on energy and water exchange processes between the ground and atmosphere require further examination. Large-scale intensive monitoring networks, remote sensing investigations, and models for frozen soil are needed to clarify regional details of climate change, permafrost degradation, and their environmental effects.

Thawing permafrost and the resulting microbial decomposition of previously frozen organic carbon (C) is one of the most significant potential feedbacks from terrestrial ecosystems to the atmosphere in a changing climate. In this article we present an overview of the global permafrost C pool and of the processes that might transfer this C into the atmosphere, as well as the associated ecosystem changes that occur with thawing. We show that accounting for C stored deep in the permafrost more than doubles previous high-latitude inventory estimates, with this new estimate equivalent to twice the atmospheric C pool. The thawing of permafrost with warming occurs both gradually and catastrophically, exposing organic C to microbial decomposition. Other aspects of ecosystem dynamics can be altered by climate change along with thawing permafrost, such as growing season length, plant growth rates and species composition, and ecosystem energy exchange. However, these processes do not appear to be able to com...

An increase in snow cover on the Tibetan Plateau has been observed over the past 50 years. The frequency of snow disasters on the Plateau has also increased. Much of the Qinghai-Xizang (Tibetan) Plateau is underlain by permafrost. Some observation sites of the GEWEX Asian Monsoon Experiment (GAME)-Tibet are located in the Naqu-Anduo

This paper provides a review of permafrost modelling advances, primarily since the 2003 permafrost conference in Zurich, Switzerland, with an emphasis on spatial permafrost models, in both arctic and high mountain environments. Models are categorised according to temporal, thermal and spatial criteria, and their approach to defining the relationship between climate, site surface conditions and permafrost status. The most significant recent advances include the expanding application of permafrost thermal models within spatial models, application of transient numerical thermal models within spatial models and incorporation of permafrost directly within global circulation model (GCM) land surface schemes. Future challenges for permafrost modelling will include establishing the appropriate level of integration required for accurate simulation of permafrost-climate interaction within GCMs, the integration of environmental change such as treeline migration into permafrost response to climate change projections, and para- meterising the effects of sub-grid scale variability in surface processes and properties on small-scale (large area) spatial models. Copyright # 2008 John Wiley & Sons, Ltd.

Permafrost occupies 25% of the terrestrial surface of the Northern Hemisphere, but approximately 70% of Russia. Thus, it is not surprising that Russian researchers pioneered its scientific investigation. The first written accounts of perennially frozen ground in Russia appeared in the 17th century during a time of exploration and settlement of remote areas of Siberia. Nineteenth century investigations emphasized mapping, measuring, and describing permafrost and its thermal regime, primarily for reasons of scientific interest. About the turn of the 20th century, construction of the Trans-Siberian Railroad and other issues related to the large migration of people to Siberia instigated a trend toward more applied investigations. In his 1927 book on permafrost research, Sumgin subdivided the history of Russian permafrost studies into three periods, designated the initial accumulation of facts, the academic period, and the utilitarian period. Although these periods are not separated by precise temporal bounds,...

Differences in the summer insulative value of the zonal vegetation mat affect the depth of thaw along the Arctic bioclimate gradient. Toward the south, taller, denser plant canopies and thicker organic horizons counter the effects of warmer temperatures, so that there is little correspondence between active layer depths and summer air temperature. We examined the interactions between summer warmth, vegetation (biomass, Leaf Area Index, Normalized Difference Vegetation Index), soil (texture and pH), and thaw depths at 17 sites in three bioclimate subzones of the Arctic Slope and Seward Peninsula, Alaska. Total plant biomass in subzones C, D, and E averaged 421 g m � 2 , 503 g m � 2 , and 1178 g m � 2 respectively. Soil organic horizons averaged 4 cm in subzone C, 8 cm in subzone D, and 14 cm in subzone E. The average late-August thaw depths in subzones C, D, and E were 44 cm, 55 cm, and 47 cm respectively. Non-acidic soils in equivalent climates generally have shorter-stature sedge-dominated canopies and many frost boils, and consequently have thicker active layers than acidic soils. The trends reported here are useful for palaeo-ecological reconstructions and predictions of future ecosystem changes in the Low Arctic. Climate change will not lead to uniform thickening of the active layer, and could lead to shallower active layers in some presently dry areas due to paludification. Copyright  2003 John Wiley & Sons, Ltd.

Permafrost and periglacial geomorphology are absent from the science curriculum in most secondary schools in the United States. This is an unfortunate situation given the recent increases in development and environmental concerns in northern latitudes and high-mountain areas, and the interesting examples of basic scientific principles found in the history of research on periglacial geomorphology and permafrost. In 1997 and 1998, a University of Delaware research group studying permafrost and periglacial geomorphology in northern Alaska participated in the National Science Foundation's (NSF) Teachers Experiencing the Antarctic and Arctic (TEA) Program. In each of these years, a high school teacher and a student traveled as part of the research team to the North Slope of Alaska. They learned about the landscape, collected active-layer thickness and temperature measurements, and assisted in data analysis. Results from studies of active-layer thickness variability and ground temperature contributed to a series of long-term observations and international research on the impacts of global climate change. Since their expeditions, the teachers have shared their experiences with their classrooms and communities in several ways, including public lectures and the Internet. Classroom activities are available to the public through the TEA web site (〈http://tea.rice.edu〉). This experience may heighten public awareness of permafrost and contribute to it becoming a useful part of the secondary curriculum.

The uppermost layer of seasonal thawing above permafrost (the active layer) is an important regulator of energy and mass fluxes between the surface and the atmosphere in the polar regions. The active layer exhibits pronounced spatial variability in complex terrain, even within relatively small areas. A stochastic model was developed and used to calculate the probability density function of active-layer thickness (ALT). Equations for the mean value, variance, and higher statistical moments of ALT were derived by applying stochastic averaging to a semi-empirical model of seasonal thawing. The stochastic model was applied in a case study in the Kuparuk river region of north-central Alaska. Data on ALT collected in the period 1995–1999 at several georeferenced sites were used to calculate landcover-specific statistics of ALT. The stochastic model was used with a digital map of landforms and gridded climatological data to construct probability maps of ALT for the Kuparuk region. Results compare favorably with semi-empirical estimates of the volume of thawed soil in the Kuparuk region, but provide additional information about uncertainties associated with estimating procedures.

The permafrost regions currently occupy about one quarter of the Earth's land area.Climate-change scenarios indicate that global warming will be amplified in the polarregions, and could lead to a large reduction in the geographic extent of permafrost.Development of natural resources, transportation networks, and human infrastructurein the high northern latitudes has been extensive during the second half of the twentiethcentury. In areas underlain by ice-rich permafrost, infrastructure could be damagedseverely by thaw-induced settlement of the ground surface accompanying climatechange. Permafrost near the current southern margin of its extent is degrading, andthis process may involve a northward shift in the southern boundary of permafrostby hundreds of kilometers throughout much of northern North America and Eurasia.A long-term increase in summer temperatures in the high northern latitudes couldalso result in significant increases in the thickness of the seasonally thawed layerabove permafrost, with negative impacts on human infrastructure located on ice-richterrain. Experiments involving general circulation model scenarios of global climatechange, a mathematical solution for the thickness of the active layer, and digitalrepresentations of permafrost distribution and ice content indicates potential forsevere disruption of human infrastructure in the permafrost regions in response toanthropogenic climate change. A series of hazard zonation maps depicts generalizedpatterns of susceptibility to thaw subsidence. Areas of greatest hazard potential includecoastlines on the Arctic Ocean and parts of Alaska, Canada, and Siberia in whichsubstantial development has occurred in recent decades.

Although maps of active-layer thickness have useful roles in geocryology, polar ecology, and hydrology, a lack of geographically distributed data at appropriate scales has prevented their widespread implementation. The n-factor (ratio of temperature at the soil surface to that in the air) has considerable potential as a tool for mapping active-layer thickness and other geocryological parameters by providing refinements to relatively simple analytic solutions for the depth of thaw. Although temperature data from the soil surface under representative land-cover units have rarely been collected historically, recent advancements in data-logger technology allow the variability of soil-surface temperature regimes to be assessed inexpensively over small temporal and spatial intervals. Temperature data collected in the air at 2 m height and at the soil surface within 10 representative land-cover units in the Kuparuk River region of north-central Alaska were used to compute seasonal n-factor values for specific ve...

The n-factor, or ratio of the seasonal degree-day sum at the soil surface to that in the air at standard screen height, has been used for more than 40 yr in engineering studies to parameterize the ...

The initial response of permafrost to global warming could be an increase in active-layer thickness. Given that such changes could have severe consequences for human infrastructure and ecosystem stability, it is important to obtain information about spatial variations of the active layer corresponding to current climatic conditions, and to determine the magnitude of possible near-surface permafrost degradation associated with climatic change. Simple analytical solutions for frost and thaw penetration depth have long been available, but were used primarily for practical applications at point locations in cold-region engineering. One of these methods, developed at Moscow State University by Kudryavtsev and co-workers, was used to develop a spatially distributed analytic model that estimates the maximum annual depth of thaw. Kudryavtsev’s procedures account for the effects of snow cover, vegetation, soil moisture, thermal properties, and regional climate, and provide estimates of surface temperature and active-layer thickness. GIS techniques were used to incorporate climate records, digital cartographic products, and field data into a spatially distributed estimate of active-layer thickness. Procedures were applied over a rectangular 22 300 km2 area in north-central Alaska containing complex patterns of topography, vegetation, and soils. Validation procedures indicate that the Kudrayavtsev solution, adapted for spatial applications, yields accuracy and spatial resolution comparable to an existing semi-empirical method. The simplicity and low data requirements of the Kudryavtsev solution make it readily adaptable to different geographic scales and areas. The method has potential applications in climate-change studies.

To examine the scales at which the maximum variability of active-layer thickness occurs within local areas, a nested sampling and analysis design was implemented in five 1-km2 areas distributed over two physiographic provinces in north-central Alaska. The primary variations of thaw depth in the low-relief terrain of the Arctic Coastal Plain province occur over distances between 100 and 300 m, and are superimposed on a trend related to the regional climatic gradient. In the Arctic Foothills province, much of the variation within the study areas occurs over horizontal distances less than 3 m, and is superimposed on mesoscale variations induced by terrain climate. To achieve maximum effectiveness, research programs concerned with sampling, interpolating, or modeling thaw depth and closely related phenomena should be designed to accommodate substantial variability at multiple spatial scales.

Active-layer thickness was determined in late August 1995 and 1996 at 100 m intervals over seven 1 km 2 grids in the Arctic Coastal Plain and Arctic Foothills physiographic provinces of northern Alaska. Collectively, the sampled areas integrate the range of regional terrain, soil, and vegetation characteristics in this region. Spatial autocorrelation analysis indicates that patterns of active-layer thickness are governed closely by topographic detail, acting through near-surface hydrology. On the coastal plain, maximum variability occurs at scales involving hundreds of meters, and patterns were similar in the two years. Substantially less spatial structure and interannual correspondence were found within the foothill sites, where high variability occurs over smaller distances. The divergence in patterns of thaw depth between the two provinces reflects the scale of local terrain features, which predetermines the effectiveness of fixed sampling intervals. Exploratory analysis should be performed to ascertain the scale(s) of maximum variability within representative areas prior to selection of sampling intervals and development of long-term monitoring programs.

Studies and models of trace-gas flux in the Arctic consider temperature and moisture to be the dominant controls over land–atmosphere exchange1,2, with little attention having been paid to the effects of different substrates. Likewise, current Arctic vegetation maps for models of vegetation change recognize one or two tundra types3,4 and do not portray the extensive regions with different soils within the Arctic. Here we show that rapid changes to ecosystem processes (such as photosynthesis and respiration) that are related to changes in climate and land usage will be superimposed upon and modulated by differences in substrate pH. A sharp soil pH boundary along the northern front of the Arctic Foothills in Alaska separates non-acidic (pH > 6.5) ecosystems to the north from predominantly acidic (pH < 5.5) ecosystems to the south. Moist non-acidic tundra has greater heat flux, deeper summer thaw (active layer), is less of a carbon sink, and is a smaller source of methane than moist acidic tundra.

This chapter examines effects of climate change on human infrastructure in permafrost regions of Siberia. The presence and dynamic nature of ice-rich permafrost constitute a distinctive engineering environment. Many engineering problems in Siberia are associated with (1) changes in the temperature of the upper permafrost, (2) increased depth of seasonal thaw penetration, and (3) progressive thawing and disappearance of permafrost. These changes can lead to loss of soil bearing strength, increased soil permeability, and increased potential for development of such cryogenic processes as differential thaw settlement and heave, and development of thermokarst terrain. Each of these phenomena has the capacity for severe negative consequences on human infrastructure in the high latitudes. Results to date indicate that major permafrost-related impacts have already been detected in many Siberian regions, including changes in the temperature and distribution of permafrost, thickening of the seasonally thawed layer (the active layer), and changes in the distribution and quantity of ice in the ground. A quantitative geographic assessment of the ability of frozen ground to support engineering structures under rapidly changing climatic conditions in a variety of settings is provided in this chapter. Results show substantial decreases of permafrost bearing capacity over the last 40 years in some regions of Northern Siberia. Although a substantial proportion of reported deformations of structures and buildings on permafrost can be attributed to climatic warming, other technogenic factors have to be considered. The socioeconomic crisis resulted in reduced infrastructure monitoring and maintenance in many cities on permafrost during the early 1990s which have greatly contributed to the decrease in infrastructure stability.

This chapter summarizes the volume content focusing on land change in Siberia. The volume is compilation of results of the most recent international studies of Earth’s system interactions including biogeochemical and water cycles, natural ecosystems changes, and human impacts on environment. Outstanding scientific challenges are outlined as they were discussed in each chapter.

[1] A continuous time series of annual soil thaw records, extending from 1994 to 2009, is available for comparison with the records of thaw obtained from the Biocomplexity Experiment (BE) for the period 2006–2009. Discontinuous records of thaw at Barrow from wet tundra sites date back to the 1960s. Comparisons between the longer records with the BE observations reveal strong similarities. Records of permafrost temperature, reflecting changes in the annual surface energy exchange, are available from the 1950s for comparison with results from measurement programs begun in 2002. The long-term systematic geocryological investigations at Barrow indicate an increase in permafrost temperature, especially during the last several years. The increase in near-surface permafrost temperature is most pronounced in winter. Marked trends are not apparent in the active-layer record, although subsidence measurements on the North Slope indicate that penetration into the ice-rich layer at the top of permafrost has occurred over the past decade. Active-layer thickness values from the 1960s are generally higher than those from the 1990s, and are very similar to those of the 2000s. Analysis of spatial active-layer observations at representative locations demonstrates significant variations in active-layer thickness between different landscape types, reflecting the influence of vegetation, substrate, microtopography, and, especially, soil moisture. Landscape-specific differences exist in the response of active-layer thickness to climatic forcing. These differences are attributable to the existence of localized controls related to combinations of surface and subsurface characteristics. The geocryological records at Barrow illustrate the importance and effectiveness of sustained, well organized monitoring efforts to document long-term trends.

[1] Several model-based assessments predict a discernible increase in the depth of seasonal thawing and circumpolar-scale warming of permafrost by the mid-21st century. Quantitative estimates of the environmental and socioeconomic impacts of changing climate in northern regions require robust projection of changes in permafrost, which in turn depend on the availability of appropriate models and forcing data. We examined four high-resolution, hemispheric-scale gridded sets of monthly temperature and precipitation constructed using different interpolation routines and reanalysis of data from a large number of weather stations. At many of 455 Russian weather stations, the four data sets depart from empirical mean annual air temperatures averaged over the 15-year period by 1–2°C and in cumulative daily positive temperature sums (degree days of thawing) by more than 200°C days. A permafrost model, forced with the gridded climatic data sets, was used to calculate the large-scale characteristics of permafrost in northern Eurasia. We analyzed zonal-mean air and ground temperatures, depth of seasonal thawing, and area occupied by near-surface permafrost in Eurasia north of 45°N. The 0.5–1.0 °C difference in zonal-mean air temperature between the data sets translates into a range of uncertainty of 10–20% in estimates of near-surface permafrost area, which is comparable to the extent of changes projected for the following several decades. We conclude that more observations and theoretical studies are needed to improve characterization of baseline climatic conditions and to narrow the range of uncertainties in model-based permafrost projections.

[1] The Hovsgol mountain region (49°–52°N, 98°–102°E) of northern Mongolia contains widespread mountain permafrost and comprises the southern fringe of the Siberian continuous permafrost zone. In this paper, we report our initial monitoring of permafrost by means of measuring ground temperatures and active layer thickness in boreholes and some cryogenic processes under the influence of climate warming and human activities in the region. The average rate of increase in mean annual permafrost temperatures is from 0.2°C to 0.4°C per decade. Permafrost has been degrading more intensively during the last 15 years (since 1990s) than during the previous 15–20 years (1970s and 1980s). Recent degradation of permafrost under climate warming in the Hovsgol mountain region is generally more intensive than in the Hentei and Hangai Mountain regions. Moreover, livestock grazing in some local areas accelerates degradation of permafrost due to loss of vegetation cover. Year-round temperature recordings by data loggers placed beneath different vegetation covers showed marked differences in active layer thickness and ground temperature.

[1] In this study we compare gridded active layer thickness (ALT) fields representing northern Alaska produced by the State Hydrological Institute (SHI), National Snow and Ice Data Center (NSIDC), and Geophysical Institute–University of Alaska Fairbanks (UAF-GIPL 2.0) spatial permafrost models. Comparison of model-produced ALT fields representing northern Alaska revealed substantial differences. The largest difference in modeled ALT was found in the interior of Alaska. However, the spatial distribution of observational sites, most of which are on the North Slope, precludes definitive conclusions about the accuracy of model prediction for the Alaskan interior. Accuracy of the model-produced ALT fields was assessed at a series of monitoring sites and over a 27,000 km2 region in north-central Alaska with known spatial ALT distribution. The NSIDC model is very accurate over the extent of the topographically homogeneous Coastal Plain but overestimates ALT in more complex terrain of the Brooks Range Foothills. The UAF-GIPL 2.0 model reproduced site-specific active layer values well but overestimated ALT on the Coastal Plain. Although the SHI model provided relatively accurate estimates, it was unable to reproduce interannual active layer dynamics. Large differences in ALT fields have primarily resulted from differences in approaches adopted in each model for characterization of largely unknown spatial distribution of surface (vegetation, snow) and subsurface (soil properties, soil moisture) conditions. Results from this study identify the nature and magnitude of error in ALT fields produced by permafrost models.