Climate Change, Permafrost, and Impacts on Civil Infrastructure

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U.S. Arctic Research Commission Permafrost Task Force Report

December 2003

Special Report 01-03 Executive Summary

Permafrost, or perenially frozen ground, is a critical component of the cryosphere and the Arctic system. Permafrost regions occupy approximately 24% of the terrestrial surface of the Northern Hemi- sphere; further, the distribution of subsea permafrost in the Arctic Ocean is not well known, but new occurrences continue to be found. The effects of climatic warming on permafrost and the seasonally thawed layer above it (the active layer) can severely disrupt ecosystems and human infrastructure such as roads, bridges, buildings, utilities, pipelines, and airstrips. The susceptibility of engineering works to thaw-induced damage is particularly relevant to communities and structures throughout northern Alaska, Russia, and Canada. It is clear from the long-term paleographic record in these areas that climatic warming can lead to increases in permafrost temperature, thickening of the active layer, and a reduction in the percentage of the terrestrial surface underlain by near-surface permafrost. Such changes can lead to extensive settlement of the ground surface, with attendant damage to infrastructure. To advance U.S. and international permafrost research, the U.S. Arctic Research Commission in 2002 chartered a task force on climate change, permafrost, and infrastructure impacts. The task force was asked to identify key issues and research needs to foster a greater understanding of global change impacts on permafrost in the Arctic and their linkages to natural and human systems. Permafrost was found to play three key roles in the context of climatic changes: as a record keeper (temperature archive); as a translator of climatic change (subsidence and related impacts); and as a facilitator of climatic change (impact on the global carbon cycle). The potential for melting of ice-rich permafrost constitutes a significant environmental hazard in high-latitude regions. The task force found evidence of widespread warming of permafrost and observations of thawing —both conditions have serious, long-term implications for Alaska’s transportation network, for the Trans-Alaska Pipeline, and for the nearly 100,000 Alaskan cit- zens living in areas of permafrost. Climate research and scenarios for the 21st century also indicate that major settlements (such as Nome, Barrow, Inuvik, and Yakutsk) are located in regions of moderate or high hazard potential for thawing permafrost. A renewed and robust research effort and a well-informed, coordinated response to impacts of changing permafrost are the responsibilities of a host of U.S. federal and state organizations. Well-planned, international polar research, such as the International Polar Year, is urgently needed to address the key scientific questions of changing permafrost and its impacts on the carbon cycle and overall global environment. Key task force recommendations include: review by funding agencies of their interdisciplinary Arctic programs to ensure that permafrost research is integrated in program planning and execution; development of a long-term permafrost research program by the U.S. Geological Survey; enhanced funding for permafrost research at the U.S. Army Corps of Engineers Cold Regions Research and Engineering Laboratory; adoption of the Global Hierarchical Observing Strategy in all permafrost monitoring programs; development of a high-resolution permafrost map of Alaska, including the offshore; development of new satellite sensors optimized for monitoring the state of the surface, temperature, moisture, and ground ice; full incorporation of permafrost hydrology, hydrogeology, and geomorphology in new Arctic research programs of the U.S. National Science Foundation; incorporation of permafrost research in all U.S. and international programs devoted to the global carbon cycle; enhanced and long-term funding for the U.S. Frozen Ground Data Center; and substantially increased federal funding for contaminants research in cold regions, including studies on the impacts of regional warming, predictive modeling, and mitigation techniques. The task force report makes specific recommendations to eight U.S. federal agencies, the State of Alaska, and the U.S. National Research Council. Many of the recommendations will be incorporated in future Arctic research planning documents of the Commission, including its biennial Report on Goals and Objectives. The task force report will also be presented to the U.S. Interagency Arctic Research Policy Committee and to appropriate international bodies, including the International Arctic Science Com- mittee and the Arctic Council.

Cover: Map of permafrost zonation in Alaska (modified from Brown et al., 1997, 1998). Dark blue: zone of continuous permafrost. Light blue: zone of discontinuous permafrost. Yellow: zone of sporadic permafrost. Background shows a network of active ice-wedge polygons on the North Slope of Alaska. Climate Change, Permafrost, and Impacts on Civil Infrastructure

U.S. Arctic Research Commission

Permafrost Task Force Report

December 2003

Permafrost Task Force Members

Dr. Kenneth M. Hinkel Dr. Orson Smith Professor of Geography Professor of Engineering University of Cincinnati University of Alaska Anchorage

Dr. Frederick E. Nelson Walter Tucker Professor of Geography Geophysicist, U.S. Army Cold Regions University of Delaware Research and Engineering Laboratory

Walter Parker Dr. Ted Vinson Former Commissioner, U.S. Arctic Professor of Geotechnical Engineering Research Commission Oregon State University Parker Associates, Anchorage Dr. Lawson W. Brigham Dr. Vladimir Romanovsky Deputy Executive Director Associate Professor U.S. Arctic Research Commission Geophysical Institute University of Alaska Fairbanks REFERENCE CITATION

U.S. Arctic Research Commission Permafrost Task Force (2003) Climate Change, Permafrost, and Impacts on Civil Infrastructure. Special Report 01-03, U.S. Arctic Research Commission, Arlington, Virginia.

ii Acknowledgments

Lead Authors and Editors Dr. Frederick E. Nelson Dr. Lawson W. Brigham University of Delaware U.S. Arctic Research Commission

Contributing Authors

Dr. Kenneth M. Hinkel Dr. Orson Smith University of Cincinnati University of Alaska Anchorage

Walter Parker Walter Tucker Parker Associates, Anchorage U.S. Army Cold Regions Research and Engineering Laboratory Dr. Vladimir E. Romanovsky Geophysical Institute Dr. Ted Vinson University of Alaska Fairbanks Oregon State University

Dr. Nikolay I. Shiklomanov University of Delaware

Contributors

Dr. David M. Cole William Lee U.S. Army Cold Regions Research University of Alaska Anchorage and Engineering Laboratory Amanda Saxton Anna E. Klene U.S. Arctic Research Commission University of Montana

iii MESSAGE FROM THE CHAIR

This report on Climate Change, Permafrost, and Effects on Civil Infrastructure is the result of the outstanding efforts of a team of experts serving as Special Advisors to the Arctic Research Commission. The Commissioners authorized this report in order to bring the Nation’s attention to the connections between climate change research and the changes to civil infrastructure in northern regions that will come about as permafrost changes.

The Commission believes strongly that basic research has important connections to the way our citizens live and work. The study of climate change is an interesting discipline, but it is important to carry the results and predictions of these changes through to their effects on roads, bridges, buildings, ports, pipelines, and other infrastructure. This report suggests future research programs for the federal agencies, programs that the Commission will incorporate into our recommendations to the Interagency Arctic Research Policy Committee in our biennial Report on Goals and Objectives for Arctic Research.

The Commission is grateful for the effort and enthusiasm of the Task Force on Climate Change, Permafrost, and Civil Infrastructure and commends their efforts. Without this voluntary effort by the community of researchers, the Commission would be unable to help the residents of the North to cope with the changing and occasionally extreme environment in which they live.

iv Climate Change, Permafrost, and Impacts on Civil Infrastructure

Contents

Executive Summary ...... inside front cover

Permafrost Task Force Members ...... i

Acknowledgments ...... iii

Chapter 1: Permafrost and Its Role in the Arctic ...... 1

Chapter 2: Future Climate Change and Current Research Initiatives...... 13

Chapter 3: Impacts on Infrastructure in Alaska and the Circumpolar North ...... 25

Chapter 4: Findings and Agency Recommendations ...... 35

References...... 44

Glossary ...... 57

List of Acronyms ...... 61

v vi Chapter 1

PERMAFROST AND ITS ROLE IN THE ARCTIC

1.1 Introduction researchers, and not well integrated with other branches of cold regions research. Owing to Climate-change scenarios indicate that human- the importance of permafrost for development caused, or anthropogenic, warming will be over much of its territory, the situation in the most pronounced in the high latitudes. Empiri- former Soviet Union was distinctly different, with cal evidence strongly indicates that impacts a large institute in Siberia and departments in related to climate warming are well underway the larger and more prestigious universities in the polar regions (Hansen et al., 1998; Mori- devoted exclusively to permafrost research. son et al., 2000; Serreze et al., 2000; Smith et Several factors converged in the late 1980s al., 2002). These involve air temperature (Pav- and early 1990s to integrate permafrost research lov, 1997; Moritz et al., 2002), vegetation into the larger spheres of international, systems, (Myneni et al., 1997; Sturm et al., 2001), sea and global-change science: ice (Bjorgo et al. 1997), the cumulative mass • Easing of Cold-War tensions facilitated balance of small glaciers (Dyurgerov and Meier, interactions between Soviet and western 1997; Serreze et al., 2000; Arendt et al., 2002), scientists. Conferences held in Leningrad ice sheets and shelves (Vaughan et al., 2001; (Kotlyakov and Sokolov, 1990), Yamburg, British Antarctic Survey, 2002; Rignot and Siberia (Tsibulsky, 1990), and Fairbanks Thomas, 2002), and ground temperature (Weller and Wilson, 1990) during the late (Lachenbruch and Marshall, 1986; Majorowicz 1980s and early 1990s were instrumental and Skinner, 1997). in achieving international agreements. Many of the potential environmental and • Publicity about the impacts of climate socioeconomic impacts of global warming in the warming in the polar regions followed sev- high northern latitudes are associated with eral decades of unprecedented resource permafrost, or perennially frozen ground. The development in the Arctic and raised con- effects of climatic warming on permafrost and cerns about the stability of the associated the seasonally thawed layer above it (the active infrastructure (Vinson and Hayley, 1990). layer) can severely disrupt ecosystems and • The global nature of climate change made human infrastructure and intensify global warm- apparent the need for widespread cooper- ing (Brown and Andrews, 1982; Nelson et al., ation, both within the permafrost research 1993; Fitzharris et al., 1996; Jorgenson et al., community and between permafrost 2001). Until recently, however, permafrost has researchers and those engaged in other received far less attention in scientific reviews branches of science (Tegart et al., 1990). and media publications than other cryospheric • Permafrost scientists became increasingly phenomena affected by global change (Nelson aware of the benefits accruing from the et al., 2002). development of data archives and free Throughout most of its history, permafrost exchange of information (Barry, 1988; Barry science in western countries was idiosyncratic, and Brennan, 1993). Moreover, the increas- performed by individuals or small groups of ingly integrated nature of arctic science 2 Climate Change, Permafrost, and Impacts on Infrastructure

The Ground Temperature Profile

Figure 1 shows a typical temperature profile through permafrost, from the ground surface to the base of the permafrost. Higher temperatures are to the right and lower to the left; 0°C is represented as a dashed vertical line. The heavier curves show current conditions. The summer profile curves to the right, indicating above-freezing temperatures near the ground surface. The winter profile curves to the left, indicating that the lowest temperatures are experienced at the surface, with higher temperatures deeper in the permafrost. The summer and winter profiles intersect at depth; below this point, temperatures are not affected by the seasonal fluctuations at the surface. The ground warms gradually with depth in response to the geothermal gradient. The base of the permafrost is situated where the temperature profile crosses 0°C. The active layer is a layer of earth material between the ground surface and the permafrost table that freezes and thaws on an annual basis. In its simplest approximation, climate warming can be envisioned as a shift of the temperature profile to the right, as shown by the gray curves. The surface temperatures in summer and winter are higher, the active layer is thicker, and the mean annual temperature at the thermal damping depth is higher. In time, the base of the permafrost thaws and moves toward the surface. Thus, the permafrost body warms and thins as thaw progresses both above and below. Figure 1. Ground temperature profile.

demands widespread cooperation and col- land and Ladanyi (1994), Davis (2001), and laboration. Some funding agencies, such as Hallet et al. (2004). Péwé (1983a) reviewed the U.S. National Science Foundation, now the distribution of permafrost in the cordillera require, as a condition of funding, that data of the western U.S.; Walegur and Nelson (2003) be made accessible to all interested par- discussed its occurrence in the northern Appa- ties. lachians. Péwé (1983c) outlined the distribu- U.S. scientists have made major contribution of permafrost and associated landforms in tions to the study of frozen ground (geocryol- the U.S. during the last continental glaciation. ogy), particularly since World War II. Useful Permafrost science employs a complex and English-language reviews, many with empha- occasionally confusing lexicon derived from sis on Alaska, have been provided by Muller several languages and scientific disciplines. A (1947), Black (1950), Terzaghi (1952), Stearns brief Glossary and a List of Acronyms at the (1966), Ives (1974), Washburn (1980), Anders- end of this document provide assistance for nav- Chapter 1. Permafrost and its Role in the Arctic 3 igating unfamiliar terminology. A more compre- situations where, unlike Figure 1, the bottom of hensive glossary, published under the auspices the active layer is not in direct contact with the of the International Permafrost Association top of the permafrost, the permafrost is a relic (IPA), is readily available (van Everdingen, of a past colder interval and may be substan- 1998). tially out of equilibrium with the contemporary climate. 1.2 Background and Concepts 1.2.2 Landforms 1.2.1 Thermal Regime Many distinctive landforms exist in perma- Two classes of frozen ground are generally frost regions, although only some unambiguously distinguished: seasonally frozen ground, which indicate the presence of permafrost. Surface freezes and thaws on an annual basis, and features formed under cold, nonglacial condi- perennially frozen ground (permafrost), tions are known as periglacial landforms defined as any subsurface material that remains (Washburn, 1980; French, 1996) (Fig. 2). One at or below 0ºC continuously for at least two periglacial feature that serves as a good indica- consecutive years. The term permafrost is tor of the presence of permafrost is ice applied without regard to material composition, wedges—vertical ice inclusions created when phase of water substance, or cementation. water produced from melting snow seeps into Permafrost can be extensive in areas where cracks formed in fine-grained sediments during the mean annual temperature at the ground sur- severe cold-weather events earlier in winter. face is below freezing. Because the tempera- Repeated many times over centuries or millen- ture at the surface and the temperature in the nia, this process produces tapered wedges of air often differ substantially (Klene et al., 2001), foliated ice more than a meter wide near the and because of differences in the thermal con- surface and extending several meters or more ductivity of many soils in the frozen and unfro- into the ground. Viewed from the air, networks zen states (the thermal offset), permafrost can of ice wedges form striking polygonal patterns exist for extended periods at locations with mean over extensive areas of the Arctic (Lachen- annual air temperatures above 0ºC (Goodrich, bruch, 1962, 1966). Other landforms diagnostic 1982). Climate statistics do not, therefore, pro- of the presence of permafrost are pingos— vide a reliable guide to the details of permafrost ice-cored hills frequently over 10 m in height distribution. Although ultimately a climatically that can form when freezing fronts encroach determined phenomenon, the presence or from several directions on saturated sediments absence of permafrost is strongly influenced by remaining after drainage of a deep lake local factors, including microclimatic variations, (Mackay, 1998). Palsas—smaller, mound- circulation of ground water, the type of vegeta- shaped forms often found in subarctic peat- tion cover, and the thermal properties of sub- lands—can form through a variety of mecha- surface materials. nisms (Nelson et al., 1992). The range of temperatures experienced Other periglacial landforms occur frequently annually at the ground surface in typical perma- in association with permafrost but are not nec- frost terrain decreases with depth, down to a essarily diagnostic of its presence. When level at which only minute annual temperature ice-rich permafrost or another impermeable variation occurs, termed the damping depth or layer prevents infiltration of water, the soil on a level of zero annual amplitude. The active hillside may become vulnerable to a slow, flow- layer above permafrost often experiences com- like process known as solifluction, giving rise plex heat-transfer processes (Hinkel et al., 1997; to a network of lobes and terraces that impart a Kane et al., 2001). Below the permafrost crenulated or festooned appearance to the slope. table—the upper limit of material that experi- Other small landforms frequently encountered ences a maximum annual temperature of 0ºC— in subpolar and polar regions, collectively heat transfer occurs largely by conduction. In referred to as patterned ground, include small 4 Climate Change, Permafrost, and Impacts on Civil Infrastructure

a. Large pingo near Prudhoe Bay, Alaska. b. Palsa at MacMillan Pass, near the Yukon–NWT border.

c. Detachment slide in the Brooks Range foothills. d. Large-diameter sorted patterned ground, Cathedral Massif, northwestern British Columbia.

Figure 2. Periglacial landforms often associated with permafrost. Chapter 1. Permafrost and its Role in the Arctic 5 hummocks and networks of striking geometric subsea permafrost also occur around the land forms arranged into circles, polygons, or stripes margins of the Arctic Ocean, much of it ice of alternating coarse- and fine-grained sediment. rich (Brown et al., 1997; Danilov et al., 1998). The distribution of offshore permafrost is not 1.2.3 Permafrost Distribution well known, and new occurrences are found The permafrost regions occupy approxi- frequently. As shown in Figure 3, the distribu- mately 24% of the terrestrial surface of the tion of permafrost is often classified on the basis Northern Hemisphere (Brown et al., 1997; of its lateral continuity. In the Northern Hemi- Zhang et al., 1999, 2003). Substantial areas of sphere the various classes form a series of

Figure 3. Permafrost zonation in the Northern Hemisphere. Zones are defined on the basis of percentage of land surface underlain by permafrost: continuous zone, 90–100%; discontinuous zone, 50–90%; sporadic zone, 10–50%; isolated patches, 0–10%. The 1997 map on which this figure is based is the first detailed document to show permafrost distribution in the Northern Hemisphere based on standardized mapping criteria. [After Nelson et al. (2002) adapted from Brown et al. (1997, 1998).] 6 Climate Change, Permafrost, and Impacts on Civil Infrastructure

Figure 4. Latitudinal profile through the permafrost zones in Alaska, extending from the vicinity of Chikaloon in the Interior to Prudhoe Bay near the Arctic Ocean. Near the southern boundary, where the average annual temperature is around 0°C, isolated permafrost bodies may exist sporadically at depth. As the mean annual temperature decreases with increasing latitude, discontinuous permafrost bodies become larger and thicker, existing where local conditions are favorable, for example, concentric zones that conform crudely to the as the Rockies, Andes, Alps, and Himalayas, a on north-facing slopes. parallels of latitude (Fig. 4). Southward devia- response to progressively lower mean annual At average annual tem- tions in the extent of permafrost in Siberia and temperatures at higher elevations. Given suffi- peratures around –5°C, central Canada are a response to lower mean cient altitude and favorable local conditions, permafrost in Alaska is annual temperatures in the continental interiors. patches of permafrost can exist even in the sub- essentially continuous, In the zone of continuous permafrost, tropics, such as in the crater of Mauna Kea and in northern Alaska perennially frozen ground underlies most loca- (4140 m above sea level) on the island of Hawaii it extends to depths of tions, the primary exception being under large (Woodcock, 1974). over 400 m, although bodies of water that do not freeze to the bottom The thickness of permafrost is determined local unfrozen zones annually. In the discontinuous zone, perma- by the mean annual temperature at the ground (taliks) may exist frost may be widespread, but a substantial pro- surface, the thermal properties of the substrate, beneath large rivers and portion of the land surface can be underlain by and the amount of heat flowing from the earth’s lakes. The active layer seasonally frozen ground, owing to variations in interior. Permafrost thicknesses range from very can be quite thick in the such local factors as vegetation cover, snow thin layers only a few centimeters thick to about sporadic permafrost depth, and the physical properties of subsur- 1500 m in unglaciated areas of Siberia (Wash- zone, and it decreases in face materials. Some authors also refer to a burn, 1980). In general, the thickness of lowland thickness with latitude, zone in which permafrost is sporadic, occur- permafrost increases steadily with increasing although local factors ring as isolated patches that reflect combina- latitude. can make it highly variable (Nelson et al., tions of local factors favorable to its formation 1999). Near the coast of and maintenance. Because the thermal proper- 1.2.4 Ground Ice and Thermokarst the Arctic Ocean the ties of peat are conducive to the existence of Although the presence of ice is not a criterion active layer reaches a frozen ground, subarctic bogs are the primary in the definition of permafrost, ground ice is maximum mean thick- locations of permafrost in southerly parts of the responsible for many of the distinctive features ness of only about 60 cm subarctic lowlands (Zoltai, 1971; Beilman and and problems in permafrost regions. Ice can in mid- to late August. Robinson, 2003). In the Southern Hemisphere, occur within permafrost as small individual permafrost occurs in ice-free areas of the Ant- crystals within soil pores, as lenses of nearly arctic continent and in some of the subantarctic pure ice parallel to the ground surface, and as islands (Bockheim, 1995). Permafrost is also variously shaped intrusive masses formed when extensive in such midlatitude mountain ranges water is injected into soil or rock and subse- Chapter 1. Permafrost and its Role in the Arctic 7 quently frozen. The origin and morphology of of engineering design in cold regions (Anders- ground ice are varied (Mackay, 1972), ranging land and Ladanyi, 1994; Yershov, 1998). Figure from thick layers of buried glacier ice, through 5 shows the generalized distribution of ground horizontally oriented ice lenses formed by the ice in the Northern Hemisphere. A digital data- migration of moisture to freezing fronts (segre- base on ground ice is under development at gation ice), to the distinctive polygonal networks Moscow State University (Streletskaya et al., of vertical veins known as ice wedges. If their 2003). thermal stability is preserved, perennially frozen Changes in the thickness and geographical ice-bonded sediments can have considerable extent of permafrost have considerable poten- bearing capacity and are often an integral part tial for disrupting human activities if substantial

Figure 5. Generalized distribution of ground ice in the Northern Hemisphere. Ground-ice content is expressed on a relative volumetric basis: low: 0–10%; medium: 10–20%; high: >20%. Ice-cored landforms of limited extent (e.g., pingos) are not shown. [From Nelson et al. (2002) and adapted from Brown et al. (1997, 1998).] 8 Climate Change, Permafrost, and Impacts on Civil Infrastructure

amounts of ground ice are present. Because Thermokarst and Ground Subsidence the volume is reduced when ice melts and because pore water is squeezed out during con- Thickening of the active layer has two immediate effects. First, solidation, thawing of ice-rich sediments leads decomposed plant material frozen in the upper permafrost thaws, to subsidence of the overlying ground surface, exposing the carbon to microbial decomposition, which can release often resulting in deformation of an initially level carbon dioxide and methane to the atmosphere. Second, the ice in surface into irregular terrain with substantial the upper permafrost is converted to water. In coarse materials local relief. By analogy with terrain developed such as sand and gravel, this is not necessarily a problem. How- by chemical dissolution of bedrock in areas ever, fine-grained sediments often contain excess ice in the form underlain extensively by limestone, the irregular of lenses, veins, and wedges. When ice-rich permafrost thaws, the surface created by thawing of ice-rich perma- ground surface subsides; this downward displacement of the ground frost is known as thermokarst terrain. surface is termed thaw settlement (Fig. 6). Typically, thaw settle- Thermokarst subsidence occurs when the ment does not occur uniformly over space, yielding a chaotic sur- energy balance at the earth’s surface is modi- face with small hills and wet depressions known as thermokarst fied such that heat flux to subsurface layers terrain; this is particularly common in areas underlain by ice wedges increases. The process occurs over a wide (Fig. 7). When thermokarst occurs beneath a road, house, pipeline, spectrum of geographical scale, ranging from or airfield, the structural integrity is threatened. If thermokarst highly localized disturbances associated with the occurs in response to regional warming, large areas can subside influence of individual structures to depressions and, if near the coast, can be inundated by encroaching seas. tens of meters deep and occupying many square kilometers (Washburn, 1980, p. 274). On slopes, particularly in mountainous regions, thawing of ice-rich, near-surface permafrost layers can create mechanical discontinuities in the substrate, leading to active-layer detachment slides (Figure 8b) and retrogressive thaw slumps (Lewkowicz, 1992; French, 1996), which have a capacity for damage to structures similar to other types of rapid mass movements. Thermokarst subsidence is amplified where flowing water, often occurring in linear depressions, produces thermal erosion (Figure 8e; Figure 6. Thaw settlement, which develops when ice- Mackay, 1970). Similarly, wave action in areas rich permafrost thaws and the ground surface subsides. containing ice-rich permafrost can produce extremely high rates of coastal and shoreline erosion (Walker, 1991; Wolfe et al., 1998). Anthropogenic disturbances in permafrost terrain have been responsible for striking changes over relatively short time scales. Removal or disturbance of the vegetation cover for agricultural purposes (Péwé, 1954), construction of roads and winter vehicle trails (Clar- idge and Mirza, 1981; Nelson and Outcalt, 1982; Slaughter et al., 1990), and airfields (French, 1975) have resulted in subsidence severe enough to disrupt or prevent the uses for which Figure 7. High-centered polygons near Prudhoe Bay, land was developed. A controlled experiment Alaska. This form of thermokarst terrain develops through ablation of underlying ice wedges. at the Permafrost National Test Site near Fair- banks, Alaska, caused the permafrost table to Chapter 1. Permafrost and its Role in the Arctic 9

Figure 8. Effects of thermokarst processes on natural landscapes and engineered works. (a) Massive ground ice in the Yamal Peninsula, western Siberia; (b) Active-layer detachment slide, delineated below the headwall with dashed lines. The slide is associated with the presence of massive ground ice and developed in response to a particularly warm summer in the late 1980s; (c) Network of ice-wedge polygons near Prudhoe Bay; (d) Thermokarst that developed in terrain underlain by ice wedges near Prudhoe Bay, resulting from an inadequate amount of gravel fill in road construction; (e) Severe thermokarst developed over one decade in a winter road near Prudhoe Bay; the road was constructed by stripping the organics and stacking the mats in the intervening area; (f) Building in Faro, Yukon, undergoing differential settlement because of thawing of ice-rich permafrost. [From Nelson et al., 2002.] 10 Climate Change, Permafrost, and Impacts on Civil Infrastructure

move downward as much as 6.7 m over a 26- civil facilities, and engineering maintenance sys- year period, simply by removing the insulating tems have all increased substantially in recent layer of vegetation (Linell, 1973). Even tram- decades. Rapid and extensive development has pling can trigger thermokarst (Mackay, 1970), had large costs, however, in both environmen- so agencies regulating tourism in the Arctic tal and human terms (e.g., Williams, 1986; Smith (Johnston, 1997) will have to thoroughly assess and McCarter, 1997), and these could be the relative merits of developing concentrated aggravated severely by the effects of global traffic through systems of foot trails or encour- warming on permafrost. aging more diffuse patterns of use. Develop- Construction in permafrost regions requires mental encroachment on lands traditionally used special techniques at locations where the terrain to support herbivores may increase herd densi- contains ice in excess of that within soil pores. ties to such an extent that overgrazing could Prior to about 1970, many projects in northern induce widespread thaw settlement (Forbes, Alaska and elsewhere disturbed the surface sig- 1999). Brown (1997) provided a comprehen- nificantly, triggering thermokarst processes and sive review of a wide range of anthropogenic resulting in severe subsidence of the ground disturbances affecting permafrost terrain. surface, disruption of local drainage patterns, and in some cases destruction of the engineered 1.3 Effects on Civil Infrastructure works themselves. The linear scar in Figure 8e marks the route of a winter road constructed in Thermokarst can have severe effects on 1968-69 by bulldozing the tundra vegetation and engineered structures, in many cases rendering a thin layer of soil (Anonymous, 1970). This them unusable. Because of its potential for disturbance altered the energy regime at the settlement, thawing of ice-rich permafrost con- ground surface, leading to thaw of the underly- stitutes a significant environmental hazard in ing ice-rich permafrost and subsidence of up to high-latitude regions, particularly in the context 2 m along the road (Nelson and Outcalt, 1982), of climatic change. Although hazards related to which became unusable several years after permafrost have been discussed in specialist lit- construction. erature and textbooks (e.g., Brown and Grave, Environmental restrictions in North America, 1979; Péwé, 1983b; Williams, 1986; Woo et al., based on scientific knowledge about permafrost, 1992; Andersland and Ladanyi, 1994; Koster now regulate construction activities to minimize and Judge, 1994; Yershov, 1998; Dyke and their impacts on terrain containing excess ice. Brooks, 2000; Davis, 2001), they are given scant The Trans-Alaska Pipeline, which traverses attention in most English-language texts focused 1300 km from Prudhoe Bay on the Arctic on natural hazards (e.g., Bryant, 1991; Coch, coastal plain to Valdez on Prince William Sound 1995). Much of the literature treating social near the Gulf of Alaska, carries oil at tempera- science and policy issues in the polar regions tures above 60oC. To prevent the development (e.g., Peterson and Johnson, 1995; Brun et al., of thermokarst and severe damage to the pipe, 1997) also fails to adequately consider issues the line is elevated where surveys indicated the related to permafrost. presence of excess ice. To counteract conduc- Although the permafrost regions are not tion of heat into the ground, many of the pipe- densely populated, their economic importance line’s vertical supports are equipped with heat has increased substantially in recent decades pipes that cool the permafrost in winter, lower- because of the abundant natural resources in ing the mean annual ground temperature and the north circumpolar region and improved meth- preventing thawing during summer. In several ods of extraction and transportation to popula- short sections of ice-rich terrain where local tion centers. Economic development has brought above-ground conditions required burial of the expansion of the human infrastructure: hydro- line, the pipe is enclosed in thick insulation and carbon extraction facilities, transportation net- refrigerated. works, communication lines, industrial projects, Other unusual engineering techniques devised Chapter 1. Permafrost and its Role in the Arctic 11 for ice-rich permafrost include constructing situated atop thick gravel pads or other insulat- heated buildings on piles, which allows air to ing materials. In relatively large settlements such circulate beneath the structures and prevents as Barrow, water and sewage are transported conduction of heat to the subsurface. Roads, in insulated, elevated pipes known as “utilidors” airfields, and building complexes are frequently (Fig. 9).

Figure 9. Utilidor in Barrow, Alaska. 12 Climate Change, Permafrost, and Impacts on Civil Infrastructure Chapter 2

FUTURE CLIMATE CHANGE AND CURRENT RESEARCH INITIATIVES

2.1 General Considerations permanent. Permafrost was more widespread during past episodes of continental glaciation. Climate change is one of the most pressing Evidence for the former existence of perma- issues facing science, governmental bodies, and, frost, including ice-wedge casts and pingo scars, indeed, human occupation of the earth. Because has been found in areas of North America and of the extreme temperature sensitivity of cryo- Eurasia now far removed from current perma- spheric phenomena (snow, ice, frozen ground), frost regions. Detailed environmental recon- the world’s cold regions are and will continue structions in which permafrost is a critical to be heavily impacted by climate warming. paleogeographical indicator have been pro- Moreover, climate models indicate that warm- duced for Eurasia (e.g., Ballantyne and Harris, ing will be particularly acute in the polar regions, 1994; Velichko 1984). Although the former exacerbating these impacts and broadening their extent of permafrost in North America is not as geographic distribution. Changes involving well known, evidence that it existed during colder permafrost are likely to be as profound. Owing intervals is scattered along the glacial border to its multivariate role in climate change, its from New Jersey to Washington state (Péwé, potential impact on human activities, and its 1983c). widespread distribution, permafrost is among the Abundant geological evidence also exists that most important of cryospheric phenomena. widespread thermokarst terrain developed in Recognition of the importance of permafrost response to past intervals of climatic warming. in global-change research, although slow in In parts of the unglaciated lowlands of the cen- developing, has become widespread in recent tral Sakha Republic (Yakutia) in Siberia, nearly years (e.g., McCarthy et al., 2001; Goldman, half of the Pleistocene-age surface has been 2002; Hardy, 2003). Because permafrost is affected by development of alases, steep-sided highly susceptible to long-term warming, it has thermokarst depressions as much as 20–40 m been designated a “geoindicator,” to be used as deep and occupying areas of 25 km2 or more a primary tool for monitoring and assessing (Soloviev, 1973; Koutaniemi, 1985; French, environmental change (Berger and Iams, 1996). 1996). Kachurin (1962), Czudek and Demek This chapter outlines the role of permafrost in (1970), and Romanovskii et al. (2000) attributed global-change studies and describes several the development of these Siberian alases to warm national and international programs designed to intervals during the Holocene. In arctic parts of monitor geocryological changes and ameliorate North America, thaw unconformities (Burn, their impacts on human communities. 1997), sedimentary evidence (Murton, 2001), and extensive degradation of ice-cored terrain 2.2 Permafrost and Global Change (Harry et al., 1988) attest to periods in which widespread, climatically induced thermokarst Despite implications contained in the term developed. Global warming is likely to trigger a “permafrost,” perennially frozen ground is not new episode of widespread thermokarst devel- 14 Climate Change, Permafrost, and Impacts on Civil Infrastructure

opment, with serious consequences for a large 1974; Goodrich, 1978, 1982; Burn and Smith, proportion of the engineered works constructed 1988; Romanovsky and Osterkamp, 1995, 1997, in the permafrost regions during the twentieth 2000). This situation is common in peatlands, century. which often form the southernmost occurrences Permafrost plays three important roles in the of subarctic permafrost (Zoltai, 1971). In a dry, context of climatic change (Nelson et al., 1993; unfrozen state, peat is an extremely efficient Anisimov et al., 2001): as a record keeper by thermal insulator. When saturated and frozen, functioning as a temperature archive; as a however, its thermal conductivity approaches translator of climate change through subsid- that of pure ice. In such a situation, frost pene- ence and related impacts; and as a facilitator tration in winter exceeds the depth of summer of further change through its impact on the thaw, and permafrost can form or persist, global carbon cycle. These roles are discussed despite mean annual air temperatures that would briefly in subsequent sections of this chapter otherwise preclude its existence. and are treated in more detail in Nelson et al. Permafrost records temperature changes and (1993), Anisimov et al. (2001), and Serreze et other proxy information about environmental al. (2000). changes (Lachenbruch and Marshall, 1986; Burn, 1997; Murton 2001). Because the trans- 2.2.1 Record Keeper: Permafrost fer of heat in thick permafrost occurs primarily as a Temperature Archive by conduction, it acts as a low-pass filter and Permafrost is a product of cold climates and has a “memory” of past temperatures. Through is common in high-latitude and high-elevation the use of precision sensors, temperature trends environments. Air temperature, the most influ- spanning a century or more can be recorded in ential parameter, determines the existence of thick permafrost (Lachenbruch and Marshall, permafrost, as well as its stability. Although the 1986; Clow et al., 1998; Osterkamp et al., 1998a, mean annual air temperature can be used as a b; Taylor and Burgess, 1998; Romanovsky et very general indicator of the presence of perma- al., 2003). frost, other factors are involved in determining The U.S. Geological Survey (USGS) has its thickness, including substrate composition, measured permafrost temperatures from deep thermal evolution, and groundwater distribution. boreholes in northern Alaska since the 1940s. The thickness, thermal properties, and dura- Typically, this entails lowering a precision resis- tion of the snow cover exert a profound influ- tance thermistor down the access hole and ence on permafrost (Brown and Péwé, 1973; obtaining a highly accurate and precise tem- Smith, 1975; Hinzman et al., 1991; Romanovsky perature measurement at known, closely spaced and Osterkamp, 1995; Zhang et al., 1997; Burn, depths down the borehole. Analysis of these 1998; Hinkel et al., 2003a). At sites underlain data through the mid-1980s indicates that by permafrost in Alaska, the mean annual ground permafrost on Alaska’s North Slope has gener- surface temperature is commonly 3–6ºC higher ally warmed by 2–4ºC in the past century than the mean annual air temperature. At sites (Lachenbruch et al., 1982; Lachenbruch and without permafrost, this difference can be even Marshall, 1986), although some locales show larger, reaching 7–8ºC in some years. little change or a slight cooling. Additional warm- Despite subzero mean annual air tempera- ing has occurred since that time (Clow and tures, boreal areas of central Alaska may Urban, 2002), although increased snow cover experience mean annual ground surface tem- may be responsible for a significant proportion peratures above 0oC, owing to the insulating of the temperature increase near the surface effect of low-density snow cover. Nonetheless, (Stieglitz et al., 2003). permafrost may exist at such locations because Permafrost at many Arctic locations has of a thermal offset attributable to differences experienced temperature increases in recent in the thermal properties of the substrate in the decades, including central and northern Alaska frozen and unfrozen states (Kudryavtsev et al., (Lachenbruch and Marshall, 1986; Osterkamp Chapter 2. Future Climate Change and Current Research Initiatives 15 and Romanovsky, 1999), northwestern Canada (Lauriol et al., 2002). Flora and fauna incorpo- (Majorowicz and Skinner, 1997), and Siberia rated in permafrost can be dated radiometrically (Pavlov, 1996). Temperature increases are not to determine cooling episodes. uniform; cooling has occurred recently in permafrost in northern Quebec (Allard and Baolai, 2.2.2 Translator: Permafrost 1995). More recent observations indicate, how- and Global-Change Impacts ever, that permafrost is warming rapidly in this Permafrost can translate climatic change to region (Allard et al., 2002). Serreze et al. (2000) other environmental components (Jorgenson et summarized the extent and geographic distri- al., 2001; Nelson et al., 2002). Thawing of ice- bution of recent changes in permafrost temper- rich permafrost may induce settlement of the ature in the Arctic. ground surface, which often has severe conse- In Alaska, temperature measurements made quences for human infrastructure and natural over the last two decades show that perma- ecosystems. Stratigraphic and paleogeographic frost has warmed at all sites along a north–south evidence indicates that permafrost will degrade transect spanning the continuous and most of if recent climate warming continues into the the discontinuous permafrost zones, from Prud- future (e.g., Kondratjeva et al., 1993). The hoe Bay to Glennallen (Osterkamp and Arctic’s geological record contains extensive Romanovsky, 1999). Modeling indicates that in evidence about regional, climate-induced dete- the continuous permafrost zone, mean annual rioration of permafrost. Melting of glaciers in permafrost surface temperatures vary inter- Alaska and elsewhere will increase the rates annually within a range of more than 5ºC. In of coastal erosion in areas of ice-rich perma- discontinuous permafrost, the observed warm- frost, already among the highest in the world. ing is part of a trend that began in the late 1960s. Sediment input to the Arctic shelf derived from The total magnitude of the warming at the coastal erosion may exceed that from river dis- permafrost surface since then is about 2ºC. charge (ACD, 2003). Observational data indicate that the last “wave” Degradation of ice-rich permafrost has also of recent warming began on the Arctic Coastal been documented under contemporary condi- Plain, in the Foothills, and at Gulkana in the mid- tions in central Alaska and elsewhere (e.g., 1980s and in areas of discontinuous permafrost Francou et al., 1999; Osterkamp and about 1990 (typically 1989–1991). The magni- Romanovsky, 1999; Osterkamp et al., 2000; Jor- tude of the observed warming at the perma- genson et al., 2001; Tutubalina and Ree, 2001; frost surface is about 3–4ºC at West Dock and Nelson et al., 2002; Beilman and Robinson, Deadhorse near the Arctic Ocean, about 2ºC 2003). Little is known, however, about specific over the rest of the Arctic Coastal Plain and processes associated with thawing of perma- south into the Brooks Range, and typically 0.5– frost, either as a function of time or as a three- 1.5ºC in discontinuous permafrost. At some sites dimensional process affecting the geometry of in discontinuous permafrost south of the Yukon permafrost distribution over a wide spectrum River, permafrost is now thawing from both the of geographic scale. There is urgent need to top and the bottom. Thawing of ice-rich perma- conduct theoretical, numerical, and field inves- frost is presently creating thermokarst terrain tigations to address such issues. in the Alaskan interior and is having significant It is clear from the paleogeographic record effects on subarctic ecosystems and infrastruc- that climatic warming in the polar regions can ture (Jorgenson et al., 2001). lead to increases in permafrost temperature, Permafrost also contains abundant proxy thickening of the active layer, and a reduction information about climatic change. Cryostrati- in the percentage of the terrestrial surface graphic techniques (Burn, 1997; French, 1998; underlain by near-surface permafrost. Such Murton 2001), combined with isotopic analysis, changes could lead to extensive settlement of can provide information about the increases in the ground surface, with attendant damage to active-layer thickness that occurred millenia ago infrastructure. 16 Climate Change, Permafrost, and Impacts on Civil Infrastructure

Changes in Permafrost Distribution. Anisi- Until recently, however, GCMs did not mov and Nelson (1996, 1997) investigated the incorporate permafrost and permafrost-related impact of projected climate changes on perma- processes. During the last few years the GCM frost distribution in the Northern Hemisphere community has developed a general understand- using output from general circulation models ing that, unless permafrost and permafrost- (GCMs). Predictive maps of the areal extent related properties and processes are taken into of near-surface permafrost were created using account, there is little reason to expect that the “frost index” (ratio of freezing- to thawing- GCMs will produce physically reasonable results degree-day sums) to estimate the likelihood of (Slater et al., 1998 a,b). Including permafrost in permafrost [see Nelson and Outcalt (1987) for GCMs is a major challenge to both the GCM a derivation of the frost index]. The primary and permafrost scientific communities. With- conclusion of these experiments is that a signif- out a solution to this problem, however, GCMs icant reduction in the area of near-surface cannot adequately represent arctic and subarctic permafrost could occur during the next century regions. Modeling is a powerful tool for both (Fig. 10). Smith and Riseborough (2002) climate and permafrost research. Although recently presented an alternative, very promis- there has been significant progress during the ing computational method for addressing perma- last three decades, much remains to be done. frost distribution under conditions of climate Changes in Active-Layer Thickness. The change. active layer plays an important role in cold

Figure 10. Distribution of permafrost in 2050 according to the UKTR general circulation model, based on calculations by Ansimov and Nelson (1997, Figure 2). Zonal boundaries were computed using criteria for the “surface frost number,” a dimen- sionless index based on the ratio of freezing and thawing degree-days (Nelson and Outcalt, 1987). The solid line shows the approximate southern limit of contemporary permafrost as presented in Figure 3. Areas occupied by permafrost have been adjusted slightly from those in the original publication to account for marginal effects. Chapter 2. Future Climate Change and Current Research Initiatives 17 regions because most ecological, hydrological, 100, and 1000 m on a side, with nodes evenly biogeochemical, and pedogenic activities take distributed 1, 10, or 100 m apart, respectively. place within it (Hinzman et al., 1991; Kane et The gridded sampling design allows for analysis al., 1991). The thickness of the active layer is of intra- and inter-site spatial variability (Nelson influenced by many factors, including surface et al., 1998, 1999; Gomersall and Hinkel, 2001; temperature, thermal properties of the surface Shiklomanov and Nelson, 2003). Summary cover and substrate, soil moisture, and the statistics are generated for each sample period, duration and thickness of the snow cover and thaw depth on the grid is mapped using a (Hinkel et al., 1997; Paetzold et al., 2000). Con- suitable interpolation algorithm. sequently, there is widespread variation in active- Soil and near-surface permafrost tempera- layer thickness across a broad spectrum of tures are commonly determined with thermistor spatial and temporal scales (e.g., Pavlov, 1998; sensors inserted in the ground, and subdiurnal Nelson et al., 1999; Hinkel and Nelson, 2003). readings are made manually or recorded at reg- The active layer can be thought of as a filter ular time intervals by battery-operated data- that attenuates the temperature signal as it loggers. Closely spaced thermistors in the upper travels from the ground surface into the under- sections of shallow to intermediate-depth bore- lying permafrost. The properties of this filter holes (25–125 m) provide continuous data to change with time, behaving in a radically dif- interpolate active-layer thickness and to observe ferent manner in summer and winter because interannual to decadal changes in permafrost of the changes in the phase of the water–ice temperatures. system (Hinkel and Outcalt, 1994). Over longer Changes in Soil Moisture and Ground Ice time periods, the accumulation of peat at the Content. Soil moisture content has an impor- surface, cryoturbation, and ice enrichment at tant effect on soil thermal properties, soil heat depth can alter the filter properties. Thus, to flow, and vegetation and is, therefore, a crucial understand and interpret the signal recorded in parameter. Although arctic hydrology has permafrost, monitoring programs must incorpo- received serious attention in science planning rate intensive active-layer observations. The documents, little attention has been devoted to hypothesis and existing evidence that warming subsurface hydrologic and hydrogeologic pro- will increase the thickness of the active layer, cesses in permafrost regions. The omission of resulting in thawing of ice-rich permafrost, ground and soil water as a central focus is ground instability, and surface subsidence, unfortunate, because subsurface flow and sub- require further investigation under a variety of surface storage are extremely important com- contemporary environmental settings. ponents in the arctic hydrological system and in Several monitoring methods are used to mea- the arctic water cycle as a whole. Studies of sure seasonal and long-term changes in the permafrost hydrogeology are rare in the U.S. thickness of the active layer: physical probing arctic sciences plans and programs. This is a with a graduated steel rod at the end of the serious gap in the research agenda and moni- thaw season (mid-August to mid-September), toring programs, in both the high Arctic and the temperature measurements, and stratigraphic Subarctic. observations of ground ice occurrences (e.g., Several methods are employed to measure Burn, 1997; French, 1998; Murton, 2001). Other soil moisture, including gravimetric sampling, recommended measurements include soil mois- time-domain reflectometry (TDR), and porta- ture and vertical displacement of the active layer ble soil dielectric measurements. Soil moisture by thaw subsidence and frost heave. An can vary over short distances, and near-surface extended description of monitoring methods is soil moisture fluctuates seasonally and in presented in the monograph by Brown et al. response to transient rainfall events (e.g., Miller (2000). et al., 1998; Hinkel and Nelson, 2003). Kane et Measurements of thaw depth are often col- al. (1996) had some success using satellite-based lected on plots or grids that vary between 10, synthetic aperture radar to estimate soil mois- 18 Climate Change, Permafrost, and Impacts on Civil Infrastructure

ture in the Kuparuk basin. Ground-based radar able for permafrost problems, and they can be systems (e.g., Doolittle et al., 1990; Hinkel et used with some confidence when adequate al., 2001) show considerable promise for directly information about climatic, boundary layer, and determining the long-term position of the active subsurface parameters is available. layer over limited areas. Analytical equations can also be helpful in Frozen ground supersaturated with ice (i.e., providing insights into the physics of the cou- containing excess ice) is particularly suscepti- pling between permafrost and the atmosphere. ble to thaw subsidence. Probing may not detect However, these simple equations have limited this. Careful surveying is necessary to deter- usefulness because they do not include the mine if thaw subsidence or frost heave has effects of inhomogeneous active layers with occurred, but surveying is often not feasible. multiple layers, variable thermal properties, Experiments involving high-precision (<1 cm) unfrozen water dynamics, and non-conductive differential GPS (global positioning systems) to heat flow. map and determine the scale of variability of Serious problems arise when complex heave and subsidence are underway in north- models are employed in a spatial context, ern Alaska (Little et al., 2003). particularly when little is known about the spatial Changes in active-layer thickness, accom- variability of parameters important to geo- panied by melt of ground ice and thaw cryological investigation. In such cases, settlement, can have profound impacts on local stochastic modeling (Anisimov et al., 2002) or environments (Burgess et al., 2000; Dyke and the use of analytic procedures in a GIS envi- Brooks, 2000). Where the distribution of ground ronment (Nelson et al., 1997; Shiklomanov and ice is not uniform, thawing can lead to differen- Nelson, 1999; Klene et al., 2002) may yield tial subsidence, resulting in thermokarst terrain. results superior to complex, physically based In the Sakha Republic (Yakutia) of Siberia, thaw models. depressions coalesced during warm intervals of Anisimov et al. (1997) used a series of GCM- the Holocene to form thaw basins (alases) tens based scenarios to examine changes in active- of meters deep and occupying areas of 25 km2 layer thickness in the Northern Hemisphere. The or more. Where human infrastructure has been results from these preliminary experiments built on ice-rich terrain, damage to infrastruc- indicate that increases of 20–30% could occur ture can accompany thaw settlement (Fig. 8d in many regions, with the largest relative and f); recent geographic overviews indicate increases occurring in the northernmost areas that the hazard potential associated with ice- (Fig. 11). rich permafrost is high in many parts of the Both empirical evidence (Moritz et al., 2002) Arctic (Nelson et al., 2001, 2002). and climate models (e.g., Greco et al., 1994) Modeling Strategies. Changes in the active indicate that climate warming is not geographi- layer may be substantial in coming decades. To cally homogeneous. With respect to degrad- predict such changes, modeling experiments are ing permafrost and its influence on human required. Many formulations have been used to settlement, a critical concern is the spatial calculate active-layer thicknesses and mean correspondence between areas of climate annual permafrost surface temperatures using warming (accompanied by active-layer thick- simplified analytical solutions (Kudryavtsev et ening) (Fig. 11) and those of ice-rich perma- al., 1974; Pavlov, 1980; Zarling, 1987; Balobaev, frost (Fig. 3 and 5). These relations were 1992; Aziz and Lunardini, 1992, 1993; modeled by Nelson et al. (2001, 2002); the Romanovsky and Osterkamp, 1995, 1997; Smith results from those experiments are given in and Riseborough, 1996; Nelson et al., 1997). Chapter 3. Harris et al. (2001b) have imple- For contemporary work involving locations for mented a comprehensive, observation-based which subsurface data are available, analytical approach to mapping geotechnical hazards solutions are less important than in previous related to permafrost in the European moun- decades. Numerical models are widely avail- tains. Chapter 2. Future Climate Change and Current Research Initiatives 19

Figure 11. Relative changes in active-layer thickness in 2050 according to the UKTR general circulation model, reclassed from Ansimov et al. (1997, Figure 6): low: 0–25%; medium: 25–50%; high: >50%.

2.2.3 Facilitator: Permafrost of carbon dioxide and methane concentrations and Global Carbon Impacts occur between 60º and 70ºN. Greenhouse gases Permafrost can facilitate further climate released from thawing permafrost into the atmo- change through the release of greenhouse gases sphere could create a strong positive feedback in (Rivkin, 1998; Robinson and Moore, 1999; Rob- the climate system; this topic is currently under inson et al., 2003). Because considerable quan- intensive investigation. Key questions include: tities of carbon are sequestered in the upper • What are the major mechanisms regulating layers of permafrost, a widespread increase in the distribution and associated rates of car- the thickness of the thawed layer could lead to bon transfer, transformation, and burial in the release of large quantities of CO2 and CH4 the arctic land–shelf system? to the atmosphere (Michaelson et al., 1996; • How do biogeochemical processes on the Anisimov et al., 1997; Goulden et al., 1998; margins of the Arctic Ocean influence the Bockheim et al., 1999). This in turn would create chemistry and biology of surface waters and a positive feedback mechanism that can amplify associated fluxes of CO2 at the air–water regional and global warming. (ice) interface? Concerns have been raised about the impact Answers to such questions require much more of high-latitude warming on the global carbon work on the state of offshore and onshore cycle. According to Semiletov (1999) the great- permafrost in the atmosphere–land–shelf est concentration and largest seasonal variations system in the Arctic. 20 Climate Change, Permafrost, and Impacts on Civil Infrastructure

Plants remove carbon dioxide from the radiatively active gases in the high-latitude atmosphere during photosynthesis. Carbon regions. By one estimate, carbon fluxes have dioxide is returned through plant respiration and the potential for a positive feedback on global decomposition of plant detritus. Studies on changes amounting to about 0.7 Gt per year of Alaska’s North Slope indicate a delicate bal- carbon to the atmosphere, about 12% of the ance between these two competing processes. total emission from fossil fuel use (Oechel and In some years, more CO2 is released into the Vourlitis, 1994). atmosphere, while in others more CO2 is fixed High-latitude wetlands currently account for by plants (Marion and Oechel, 1993; Oechel et about 5–10% of the global methane flux (Ree- al., 1993). In years when biomass production burgh and Whalen, 1992), and, because meth- exceeds respiration, the atmosphere is a net ane flux is related closely to the thermal regime source of carbon, which resides in plant biomass. in the active layer (Goulden et al., 1998; Nakano Regional changes in climate can alter the vege- et al., 2000), this component is likely to increase tation communities and thus alter this balance if the development of widespread thermokarst in a direction not fully understood. Studies from terrain is triggered by permafrost degradation. Canada and Eurasia have demonstrated that Thermokarst lakes emit methane during winter; many arctic sites are currently losing CO2 to methane is generated from carbon-rich terres- the atmosphere (Zimov et al., 1993, 1996). trial sediments sequestered during the Pleisto- Higher temperatures and a reduction in soil mois- cene epoch (Zimov et al., 1997). ture appear to be likely causes (Oechel et al., Embedded within sediments on the ocean 1995, 1998). margins is a crystalline form of methane known Plants lose biomass as part of their natural as gas hydrates (e.g., Yakushev and Chuvilin, growth cycle. They shed leaves and twigs, and 2000). Although currently in quasi-equilibrium they disperse seeds. In wet tundra, much of with temperature and pressure conditions, large this surface detritus decays only partially, yield- volumes of gas hydrates are susceptible to ing a surface soil layer rich in organics. The disruption by warming ocean water. This could organics can be transported deeper into the soil result in the release of these hydrocarbons, via several processes. In summer, water per- allowing them to escape to the surface and enter colating through the active layer can transport the atmosphere. Since methane has a radiative organics to depth. In winter, soils are suscepti- activity index of about 27 (molecule for mole- ble to a mechanical churning process known as cule, it is 27 times more effective at absorbing cryoturbation. Over long time periods, surface thermal radiation than CO2), this could provide materials are transported down into the soil and a strong positive feedback. can become incorporated into the upper permafrost. This storage (sequestration) of carbon in 2.3 Monitoring: Organized the upper permafrost has been documented in International Collection, several studies (Michaelson et al., 1996; Bock- Reporting, and Archiving Efforts heim et al., 1999). Terrestrial arctic ecosystems may have been a net carbon sink during the Worldwide permafrost monitoring can Holocene, and perhaps 300 gigatons are seques- provide evidence of climate-induced changes. tered (Miller et al., 1983). Standardized in-situ measurements are also Thickening of the seasonally thawed layer essential to calibrate and verify regional and effectively means downward movement of the GCM models. The Global Terrestrial Network permafrost table. If organic material is present for Permafrost (GTN-P) is the primary inter- in the newly thawed layer, it again becomes national program concerned with monitoring subject to decomposition by soil microbes, ulti- permafrost parameters. GTN-P was developed mately releasing CO2 and CH4 to the atmo- in the 1990s with the long-term goal of obtaining sphere. This can act as a positive feedback a comprehensive view of the spatial structure, mechanism by increasing the concentration of trends, and variability of changes in permafrost Chapter 2. Future Climate Change and Current Research Initiatives 21 temperature (Brown et al., 2000; Burgess et (ARCSS) program of the U.S. National Science al., 2000). The program’s two components are: Foundation, the network currently incorporates (a) long-term monitoring of the thermal state of approximately 125 active sites involving partic- permafrost in an extensive borehole network; ipants from twelve countries in the Northern and (b) monitoring of active-layer thickness and Hemisphere and three countries involved in processes at representative locations. The Antarctic research. The majority of the network active-layer program, titled Circumpolar Active sites are in arctic tundra regions, with the Layer Monitoring (CALM), is described in a remainder in warmer forested subarctic and monograph by Brown et al. (2000). alpine tundra of the mid-latitudes. Metadata and The ideal distribution of sites for a global or ancillary information are available for each site, hemispheric monitoring network should include including climate, site photographs, and descrip- locations representative of major ecological, tions of terrain, soil type, and vegetation. CALM climatic, and physiographic regions. Recently, data are transferred periodically to a perma- efforts have been made to re-establish a deep nent archive at the National Snow and Ice Data borehole temperature monitoring program under Center (NSIDC) in Boulder, Colorado. the auspices of GTN-P to monitor, detect, and assess long-term changes in the active layer and the thermal state of permafrost, particularly Web Sites on a regional basis (Burgess et al., 2000; GTN-P http://www.gtnp.org Romanovsky et al., 2002). The borehole net- CALM http://www.geography.uc.edu/~kenhinke/CALM/ work has 287 candidate sites, half of which CEON http://ceoninfo.org/ obtain data on a periodic basis. Borehole meta- FGDC http://nsidc.org/fgdc/ data are available on the Geological Survey of PACE http://www.earth.cardiff.ac.uk/research/geoenvironment/ Canada’s permafrost web site. pace/31.EU_PACE_Project.htm The International Permafrost Association IPA http://www.soton.ac.uk/ipa (IPA), with 24 member nations, serves as the international facilitator for the CALM network, which is now part of GTN-P. Prior to the 1990s, GTN-P and the CALM program contribute many data sets related to the thickness of the to the Global Terrestrial Observing System active layer were collected as part of larger (GTOS), the Global Climate Observing System geomorphological, ecological, or engineering (GCOS), and the associated Terrestrial Eco- investigations, using different sampling designs system Monitoring Sites (TEMS) network. The and collection methodologies. Moreover, the networks are co-sponsored by the World typical study was short term and did not deposit Meteorological Organization (WMO), the data records in archives accessible for general Intergovernmental Oceanographic Commission use (Barry, 1988; Clark and Barry, 1998). The (IOC of UNESCO), the United Nations Envi- combined effect of these circumstances made ronment Programme (UNEP), the International it difficult to investigate long-term changes in Council of Scientific Unions (ICSU), and the seasonal thaw depth or possible interregional Food and Agriculture Organization (FAO). A synchronicity. detailed joint plan for GCOS and GTOS was The CALM program was formally estab- developed by the Terrestrial Observational lished in the mid-1990s as a long-term observa- Panel for Climate (TOPC) for climate-related tional program designed to assess changes in observations (GCOS, 1997). Program goals the active layer and provide ground truth for include early detection of changes related to cli- regional and global models. It represents the mate, documentation of natural climate variabil- first attempt to collect and analyze a large-scale, ity and extreme events, modeling and prediction standardized geocryological data set obtained of these changes, and assessment of impacts. using methods established under an international The affiliation of GTN-P and the CALM protocol. Funded by the Arctic System Science program within the GCOS/GTOS networks 22 Climate Change, Permafrost, and Impacts on Civil Infrastructure

The GHOST Hierarchical Sampling Strategy

The GTN-P network seeks to implement an integrated, cryology due to difficulties in remotely sensing multi-level strategy for global observations of permafrost subsurface temperatures, ground ice, and frost thermal state, active layer thickness, and seasonally penetration]. frozen ground, including snow cover, soil moisture, and temperature by integrating (a) traditional approaches and Tiers 1–4 mainly represent traditional methodologies, new technologies, (b) in-situ and remote observations, which remain fundamentally important for a deeper and (c) process understanding and global coverage. The understanding of processes and long-term trends. Tier 5 provisional tiered system corresponds to the Global constitutes challenges for scaling experiments and Hierarchical Observing Strategy (GHOST) developed for regional model validation, although progress has been key variables of GTOS and includes: made in active-layer mapping (Peddle and Franklin, 1993; Leverington and Duguay, 1996; McMichael et al., 1997). Tier 1: Major assemblages of experimental sites Activation of additional existing boreholes and establish- [Kuparuk River basin, Alaska; Mackenzie River ment of new boreholes and active layer sites are required basin, Canada; Lower Kolyma River, Russia; for representative coverage in the Europe/Nordic region, Permafrost and Climate in Europe (PACE) Russia and Central Asia (Russia, Mongolia, Kazakhstan, transect from southern Europe to Svalbard]. China), in the southern hemisphere (South America, Ant- arctica), and in the North American mountain ranges and Tier 2: Process-oriented research sites [Long-term lowlands. Additional cooperative activities through the Ecological Research (LTER) sites and Barrow NSIDC Frozen Ground Data Center are required to (Alaska); Zackenberg (Greenland); Abisko obtain data from continental regions where existing sea- (Sweden); and Murtel/Corvatsch (Switzerland)]. sonal soil frost observations are collected. Figure 12, modified from Brown et al. (2000), repre- Tier 3: Range of environmental variations including sents an established application of a hierarchical, GHOST- ground temperatures and plots [CALM hectare like strategy in permafrost science. The active-layer thick- to 1-km2 grids; boreholes across landscapes ness in the 26,278-km2 area (Tier 1), centered on the gradients (southern Norway, Swiss Alps, Lake Kuparuk River basin of north-central Alaska, is mapped Hovsgol GEF in Mongolia)]. using data from the array of experimental and observation sites located within it. A wide range of intensive mon- Tier 4: Spatially representative grids associated with itoring programs and manipulative experiments are gas flux, active layer, and borehole measurements conducted at the Toolik LTER site, which represents Tier [northern Alaska and Lower Kolyma, Russia, 2. Soil and vegetation characteristics are collected at 1- including MODIS and Fluxnet sites (such as km2 Tier 3 sampling grids (squares) and are used for Barrow, Alaska)]. field experiments (e.g., frost heave and thaw settlement) and model verification. Small (1-ha) Tier 4 sites, repre- Tier 5: Application of remotely sensed data covering sented by triangles, are distributed throughout the region entire regions [low state of development in geo- and are used to collect air temperature, surface temper-

necessitates conformity with global of the rates and magnitude of global-change observational protocols whenever and wherever impacts (WMO, 1997). The basic objective of possible. The Global Hierarchical Observing GHOST site selection is to obtain valid regional Strategy (GHOST) represents a strategic effort and global coverage while taking maximum ad- to obtain samples of environmental variables vantage of existing facilities and sites. The that can be integrated systematically over time GHOST system incorporates a five-tier hierar- and space to provide comprehensive estimates chical system for surface observations; a more Chapter 2. Future Climate Change and Current Research Initiatives 23

Figure 12. Example of a GHOST-like hierarchical sampling strategy and time-series analysis, Kuparuk River basin, Alaska (Brown et al., 2000).

ature, and thaw-depth data. Vegetation and digital odologies for producing active layer maps of this region elevation model (DEM) maps of the area, derived from have been explored by Hinzman et al. (1998), Shiklo- satellite data, represent Tier 5 and are used to interpolate manov and Nelson (1999), Anisimov et al. (2002), and data over the entire map area. Details are given in Nelson Klene et al. (2001). Information about the Tier 3 et al. (1997) and Shiklomanov and Nelson (2002). The (ARCSS/CALM) grids is contained in Nelson et al. (1998) GHOST approach lends itself to a wide variety of and Hinkel and Nelson (2003). The Tier 4 (Flux Study) analytical and modeling approaches. Alternative meth- sites are discussed by Klene et al. (2001). complete generic description can be found in 2.4 Organizational Issues Version 2.0 of the GCOS/GTOS Plan for Ter- restrial Climate-related Observations (GCOS, Standardized collection of basic environmen- 1997; WMO, 1997). Permafrost observation tal parameters is essential to all large-scale sites and networks will play an important role in scientific and engineering endeavors. With the developing Circumarctic Environmental Ob- respect to permafrost, there is a clear need to servatories Network (CEON). establish a systematic data-reduction protocol 24 Climate Change, Permafrost, and Impacts on Civil Infrastructure

in accordance with identified and established groups and data committees coordinate GTN- user needs. For example, hourly air tempera- P activities, including input to GTOS/TEMS. ture data collected by an individual field The Geological Survey of Canada (Ottawa) researcher may not be necessary for climate maintains the GTN-P web site and borehole modelers and engineers. Instead, such data metadata files and coordinates thermal data could be processed to produce average daily management and dissemination The NSIDC air temperatures or accumulated degree-days acquires, stores, and processes data. Data of frost, thaw, heating, or cooling. Implicit in collected by funded projects in the U.S. should such an approach is the recognition that basic be archived in the Frozen Ground Data Center aspects of data collection would be standard- (FGDC) within an appropriate time period. ized (e.g., all air temperature measurements FGDC is a subunit of the U.S. National Snow would be made at the same height above the and Ice Data Center (NSIDC) in Boulder, ground surface using a standard radiation shield) Colorado, which is an affiliate of the World and that metadata files would also be available. Data Center for Glaciology (WDC). Details These data, if properly collected, provide the of site characteristics and measurements foundation upon which all efforts ultimately should be presented in standardized metadata depend, and they are used to refine and vali- files. date climate modeling efforts. A strategy developed by the IPA facilitates A specific measurement protocol should be data and information management to meet the developed for monitoring permafrost. This pro- needs of cold regions science and engineering. tocol should be established by the scientific and One focus of this strategy is the Global Geo- engineering community for obtaining the cryological Data (GGD) system, which provides appropriate measurements at the necessary an international link for scientific investigators temporal frequency and spatial resolution. The and data centers. In collaboration with the protocol should cover the scale of instrumenta- International Arctic Research Center (IARC), tion ranging from site to satellite. Inherent in WDC and NSIDC serve as a central node for the protocol is the requisite accuracy and pre- GGD. Every five years NSIDC prepares a CD- cision of thermistors, the optimal depth of soil ROM containing information and data acquired temperature measurements, and site descrip- in the previous five-year interval. Known as the tions. These efforts should be coordinated and Circumpolar Active-Layer Permafrost System integrated with those of the GTN-P to ensure (CAPS), this product is a comprehensive com- the collection of data useful for global climate pilation of data related to permafrost and frozen observation (Burgess et al., 2000; GTN-P web ground from a global perspective. Detailed site). Similarly, methods of monitoring active information can be found on the FGDC web layer thickness and thaw subsidence should be site. integrated with those of ongoing and develop- Data sets representing spatially intensive ing international projects (e.g., CALM, PACE, measurements, such as satellite imagery or thaw IPY) following discussion and modification of depths interpolated over large regions, should the protocols currently in place. In all cases, an be prepared in a format conducive to genera- effort should be made to assess the spatial vari- tion of descriptive statistics and standardized ability of thaw depth and soil temperature and mapping. Digital mapping at regional, continen- to collect ancillary data. A comprehensive list tal, and circumpolar scales has been facilitated of recommendations regarding permafrost- greatly by the development of the Equal-Area related activities and their coordination was Scalable Earth Grid (EASE-Grid) at NSIDC issued recently (IPA Council, 2003). (Armstrong et al., 1997). Use of this flexible The 24-member International Permafrost system of projections is recommended at these Association (IPA) and several of its working scales. Chapter 3

IMPACTS ON INFRASTRUCTURE IN ALASKA AND THE CIRCUMPOLAR NORTH

3.1 Introduction location of existing infrastructure has been superimposed on the hazard map, providing a Evidence presented in the preceding chap- general assessment of the susceptibility of ters documents widespread warming of perma- engineered works to thaw-induced damage frost, which in some cases is showing very clear under the UKTR climate-change scenario. Fig- evidence of thawing. Warming and thawing of ure 13a indicates the risk to infrastructure in permafrost will have significant effects on northern Canada, Alaska, and Russia. Russia infrastructure (Instanes, 2003). Local sources has more population centers and infrastructure of anthropogenic heat and surface modifications in the higher risk areas, but Alaska and Canada associated with urban land uses may exacer- also have population centers, pipelines, and roads bate problems related to thaw and settlement in areas of moderate and high hazard potential. (Hinkel et al., 2003b; Klene et al., 2003). After Major settlements are located in areas of mod- presenting a general overview of the possible erate or high hazard potential in central and effects of climate warming on permafrost in northern Alaska (e.g., Nome and Barrow), the Northern Hemisphere, this chapter discusses northwestern Canada (Inuvik), western Siberia the existing infrastructure in Alaska with spe- (Vorkuta), and the Sakha Republic in Siberia cial reference to its relation with permafrost. (Yukutsk). The potential for severe thaw- induced disruptions to engineered works has 3.2 Northern Hemisphere Hazards been reported from each of these areas, and problems are likely to intensify under conditions Nelson et al. (2001, 2002) used output from of global warming. three transient-mode general circulation models Figure 13b shows the risk to transportation (GCMs), in conjunction with a digital version of facilities. The network of seismic trails in north- the International Permafrost Association’s ern Alaska, the Dalton Highway between the Circum-Arctic Map of Permafrost and Yukon River and Prudhoe Bay in Alaska, the Ground Ice Conditions (Brown et al., 1997, Dempster Highway between Dawson and 1998; Brown and Haggerty, 1998), to map the Inuvik in western Canada, and the extensive hazard potential associated with thawing perma- road and trail system in central Siberia all frost under conditions of global warming. The traverse areas of high hazard potential. Numer- maps were created using a simple, dimension- ous airfields occupy ice-rich terrain in Siberia, less thaw-settlement index, computed using the and the Trans-Siberian, Baikal-Amur Mainline, relative increase in active layer thickness and Hudson Bay, and Alaska Railroads span regions the volumetric proportion of near-surface soil of lesser hazard potential, although they extend occupied by ground ice. Computational details into areas in which localized problems have been are provided in Nelson et al. (2002). The reported. A dense network of secondary roads resulting maps depict areas of low, moderate, and trails occupies areas of moderate risk in and high hazard potential. In Figure 13 the Mongolia, and northeastern China has an 26 Climate Change, Permafrost, and Impacts on Civil Infrastructure

a. Risk to infrastructure. The red dots indicate population centers; the pink shading indicates areas of human settlement.

Figure 13. Areas at risk for infrastructure damage as a result of thawing of permafrost. Chapter 3. Impacts on Infrastructure in Alaska and the Circumpolar North 27

b. Risk to transportation facilities. The yellow lines indicate winter trails, the blue lines indicate railroads, and the red dots indicate airfields.

c. Risk to major electrical transmission lines and pipelines. The blue lines indicate electrical transmission lines, the yellow lines indicate pipelines (yellow), and the black dot with red lightning is the location of the Bilibino nuclear powerplant in Russia. 28 Climate Change, Permafrost, and Impacts on Civil Infrastructure

extensive railway system developed in areas Ferrians et al. (1969), and Péwé (1954, 1983b) underlain by permafrost. by considering how warming permafrost may The risk to major electrical transmission lines affect transportation, the Trans-Alaska Pipe- and pipelines is shown in Figure 13c. Most elec- line, and community infrastructure. trical facilities, including the extensive networks in northern Scandinavia and south-central 3.3.1 Transportation Network Siberia, are located in areas of moderate risk. The State of Alaska agency primarily respon- The Bilibino nuclear station and its grid, extend- sible for transportation infrastructure is the ing from Cherskiy on the Kolyma River to Pevek Department of Transportation and Public on the East Siberian Sea, occupy an area in Facilities (ADOT&PF). The ADOT&PF dis- which increased thaw depth and abundant ice- cusses the history, present status, and plans for rich permafrost combine to produce high haz- road, rail, air, and marine transportation infra- ard potential. The Trans-Alaska Pipeline Sys- structure in its Vision 2020 Update, Statewide tem spans two areas of moderate hazard Transportation Plan (ADOT&PF, 2002). With potential. The network of pipelines associated respect to the present status of roads, this report with the West Siberia oil and gas fields is of notes that “…Alaska is twice the size of Texas, particular concern because it is located in the but its population and road mileage compare ice-rich West Siberian Plain and is vulnerable more closely with Vermont….” The state has to freeze–thaw processes (Seligman, 2000). approximately 12,700 miles of roads, about 30% Figure 13 provides a generalized delineation (less than 4,000 miles) of which are paved. of regions in the Northern Hemisphere to which Gravel and dirt roads are by far the most com- high priority should be assigned for monitoring mon design. The majority of the state’s roads permafrost conditions. At the circum-arctic are in the south-central region, where perma- scale, maps such as these are useful for devel- frost is discontinuous and sparse. Roads in the oping strategies to mitigate detrimental impacts interior, particularly north of Fairbanks (i.e., the of warming and adaptation of the economy and gravel Dalton Highway), traverse areas under- social life to the changing environment of north- lain by ice-rich permafrost and may require ern lands. Maps at such scales cannot, of course, substantial rehabilitation or relocation if thaw resolve the local factors involved in the devel- occurs. opment of thermokarst. Rather, they point to The Alaska Railroad extends from Seward geographic areas where hazard scientists, policy to Fairbanks, crosses permafrost terrain, and analysts, and engineers should focus attention has been affected by differential frost heave and prepare more detailed maps at local and and thaw settlement in places (Ferrians et al., regional scales. 1969). The railroad does not extend northward into the zone of continuous permafrost. Thaw 3.3 Geocryological Hazards in Alaska of ice-rich permafrost will increase railway maintenance costs but should not require major Figure 14 shows the population centers and relocations of the existing track. Plans to extend major roads in areas of Alaska that are pres- the track to Canada across the interior will ently affected by permafrost. Although a involve routing through permafrost areas. majority of the population resides in permafrost- Selecting a route that avoids ice-rich perma- free areas of the state, sizeable towns and set- frost foundations will increase the track mile- tlements are located in areas that are suscepti- age and construction cost. ble to permafrost degradation; nearly 100,000 Alaska has 84 commercial airports and more Alaskans live in areas vulnerable to permafrost than 3,000 airstrips. The state has 285 publicly degradation (Fig. 14). Moreover, many of the owned airports, 261 of which are owned by the state’s highways traverse areas underlain by state government, including 67 paved airstrips, permafrost. The remainder of this chapter 177 gravel airstrips, and 41 seaplane ports. Many updates earlier reviews by Muller (1947), of the state’s rural communities depend exclu- Chapter 3. Impacts on Infrastructure in Alaska and the Circumpolar North 29

Figure 14. Exposure of communities and major roads in Alaska to permafrost. (Source data: U.S. Geo- logical Survey, International Permafrost Association, and Alaska Department of Natural Resources GIS database. sively on a local airstrip for transporting pas- transportation infrastructure to thawing of sengers and freight, including heating fuel. A permafrost can and should be assessed system- significant number of airstrips in communities atically. Roads, railways, and airstrips placed of southwest, northwest, and interior Alaska are on ice-rich continuous permafrost will generally built on permafrost and will require major repairs require relocation to well-drained natural foun- or complete relocation if their foundations thaw. dations or replacement with substantially The vulnerability of Alaska’s network of different construction methods. Roads through 30 Climate Change, Permafrost, and Impacts on Civil Infrastructure

discontinuous permafrost will require this rein- Alaska has four large military bases, two of vestment for reaches built on ice-rich perma- which must contend with discontinuous permafrost. Roads and airstrips built on permafrost frost. Alaska also has 600 former defense sites. with a lower volume of ice will require rehabil- Russia has an even greater problem, with a itation, but perhaps not relocation, as the foun- significant number of population centers, indus- dation thaws. trial complexes (including one nuclear power Site-specific information is most desirable for plant), and military bases in permafrost areas this purpose, but the information contained on (Ershov et al., 2003). The continuous perma- permafrost maps can be applied to compute an frost in the far north forces essentially all facil- expected value of road miles over each cate- ities to be constructed on permafrost. Farther gory of permafrost. Figure 14 shows the major south, in areas of discontinuous permafrost, land road routes of the state and the locations of ownership and needs often force facilities to be communities, shaded to indicate whether they developed on permafrost. are situated in areas of continuous, discontinu- The permafrost underlying most of the state ous, or sporadic permafrost. Thawing of various is the key reason why Alaskan infrastructure types of permafrost is predictable by analyses will be affected by a warming climate far based on knowledge of soil conditions and air greater than any other region of the U.S. Thaw- temperature warming projections. A timeline for ing permafrost poses several types of risks to serious permafrost-related problems could be community infrastructure. Most are associated derived from projections of general circulation with the thawing of ice-rich permafrost, which, models in a manner similar to that of Nelson et when thawed, loses strength and volume. The al. (2001). Expected values of relocation and most basic risk is caused by the loss of rehabilitation can be developed, given estimates mechanical strength and eventually thaw of per-mile design and construction costs. A settlement or subsidence. Thaw settlement master plan of climate-change-induced major causes the failure of foundations and pilings, relocation and rehabilitation projects can be affecting all types of community infrastructure. formed with this information. The information Bond strengths between permafrost and piles can also be applied efficiently to locate stations are greatly reduced by rising temperatures. to monitor permafrost warming where it mat- Increases in the thickness of the active layer ters most. This effort could best be accom- can cause frost heaving of pilings and struc- plished comprehensively through the combined tures. Warming will also accelerate the erosion resources and efforts of the state and federal of shorelines and riverbanks, threatening the governments. infrastructure located on eroding shorelines. Thawing of permafrost or increasing the thick- 3.3.2 Community Infrastructure ness of the active layer can also mobilize Community infrastructure includes facilities pollutants and contaminants that are presently in urban and rural communities that are not confined (Snape et al., 2003). associated with the transportation network or Thawing permafrost and changes in the the Trans-Alaska Pipeline. Examples of com- active layer across Alaska will bring potentially munity infrastructure include private and public adverse impacts to building foundations and buildings, landfills, sewer and water facilities, support structures. The past is replete with solid waste facilities, electrical generating examples of public and private facilities that have facilities, towers, antennas, and fuel storage failed due to warming and subsidence of the tanks. Figure 14 shows the locations of settle- underlying permafrost because of improper ments in Alaska with regard to permafrost siting, design, and construction methods. Thaw susceptibility. Although the major population subsidence has resulted in numerous cases of center in the Anchorage area is largely free of expensive fixes or abandoned facilities. During permafrost, over 160 communities lie in areas new construction, if ice-rich permafrost cannot of continuous or discontinuous permafrost. be avoided, it can be addressed with proper Chapter 3. Impacts on Infrastructure in Alaska and the Circumpolar North 31 design and construction techniques. Methods For systems that discharge into streams or include digging out the permafrost if it is rela- rivers, increased stream flow and reduced ice tively shallow and thin, raising the structure on cover will help aerate and dilute the effluent. piles, or otherwise assuring that the substrate Landfills containing solid waste pose problems remains frozen through active or passive refrig- in that contaminants confined by the frozen eration. Mitigating existing problems is difficult ground may be released and transported as the and expensive, requiring reconstruction of the permafrost thaws. The problem is amplified building support system, as well as repairing the because there is often far more than solid waste damage to the structure. Warming creates in landfills and at many other locations near further problems, however. If mean annual air villages. Past practice throughout the north has temperatures rise above the freezing point, it ignored proper disposal of contaminants because will be impossible to maintain permafrost over of the associated expense and the perception the long term without expensive artificial refrig- that permafrost acts as an impermeable barrier. eration. The largest problem will be for those Some villages or facilities located on river- areas where the upper permafrost layers are banks or exposed coastlines are facing major already near the freezing point, primarily in problems with erosion (Walker and Arnborg, regions of discontinuous permafrost. Larger 1966; USACE, 1999; Walker, 2001). Warming facilities, such as schools and tank farms, will has contributed to longer ice-free seasons in be affected first. Continued warming will cause arctic areas. Riverbank erosion has destroyed problems even for those facilities that were prop- homes and public infrastructure in some villages erly designed to maintain the underlying perma- (USACE, 1999). Increased storminess and frost in its frozen state. New approaches for higher waves are eroding arctic coasts at greater maintaining existing structures and building new rates than in the past (Brown et al., 2003). The structures on permafrost must be developed to combination of increased wave action and account for increases in soil temperatures. warming permafrost especially threatens low- Thaw subsidence is also a problem for utility lying coastal villages (Walker, 2001). Several distribution networks and communications villages in Alaska have lost buildings to the sea facilities. These facilities are usually based on (Callaway et al., 1999). In some cases, entire foundations or pilings. Frost heaving of piles can villages may have to be relocated. Abandoning result from increased active-layer thickness. and rebuilding communities will have the One of the major effects of thawing ice-rich secondary effect of generating large amounts permafrost is the development of thermokarst of solid waste. terrain. Uneven surfaces created by differen- The costs associated with rehabilitating or tial thaw settlement will cause problems with abandoning community infrastructure damaged above-ground power lines, water, sewer, and by thawing permafrost will be high. Even build- fuel piped systems. Piped systems are espe- ings that have been designed for ice-rich perma- cially susceptible to settlement and subsequent frost will not survive unscathed if the tempera- leakage (Williams, 1986). ture rises to the point that systems designed to In many arctic communities, modern sewer maintain permafrost in its frozen state no longer and water facilities are non-existent. Many vil- function adequately. Electrical distribution lages still use “honeybucket” (storage and haul) systems and pipe and utilidor systems will be systems in which human waste is emptied into subject to failure from subsidence or frost a pit or lagoon in or near the town. Many of the heaving. Contaminants could be released from towns with more modern facilities also have landfills and other contaminant storage sites once lagoons where waste is dumped or piped. thought to be safe. Huge costs will be associated Sewage disposal systems that are designed for with villages that must be relocated. In one case subsurface discharge may benefit from less study by the Corps of Engineers in 1998, the extensive permafrost, increased water table costs of moving the village of Kivalina, Alaska, depth, and increased groundwater flow rates. to a nearby site were estimated at $54,000,000 32 Climate Change, Permafrost, and Impacts on Civil Infrastructure

(USACE, 1998). Other coastal and river villages some training lands unusable. Additional can be expected to have problems with warm- precautions will be necessary for contaminants ing permafrost and may require additional relo- generated by the military, some of which are cations. associated with the use of live munitions. Perma- The military has extensive facilities in Alaska. frost must be considered in Department of Two of its largest bases and a major training Defense plans for new facilities, including the facility are located in areas of discontinuous National Missile Defense sites being contem- permafrost, and they must constantly cope with plated for Alaska. problems caused by thawing permafrost (Cole, 2002). There are also 600 formerly used 3.3.3 The Trans-Alaska Pipeline defense sites in Alaska. Alaska is also used The Trans-Alaska Pipeline System (TAPS), extensively for training, requiring access by mil- the only large-diameter hot-oil pipeline to traverse itary vehicles and live firing of munitions. The environmentally sensitive permafrost terrain development of thermokarst terrain would make (Fig. 15), has been called an engineering marvel.

Figure 15. Exposure of the Trans-Alaska Pipeline to permafrost. (Source data: U.S. Geological Survey, International Permafrost Association, and Alaska Department of Natural Resources GIS database. Chapter 3. Impacts on Infrastructure in Alaska and the Circumpolar North 33

The TAPS encounters a wide variety of perma- radation as a problem. This interpretation is frost soil and temperature conditions (Kreig and based, however, on the present permafrost and Reger, 1983). To avoid permafrost degradation, climate conditions and does not consider the soil liquefaction, and subsidence, pipeline along Arctic Climate Impact Assessment predictions 434 of the 800 miles of the TAPS was elevated for the next 30 years. It is important to note on vertical support members (VSMs) (Fig. 16). that the 20-year period used to determine design The VSMs represented a new approach to standards was one of the coldest periods in engineering when they were designed in the recent Alaskan history. early 1970s. Design standards were based on The TAPS right-of-way leases from the the permafrost and climate conditions of the federal and state governments terminate in period 1950–1970. The objectives of the design 2004, and the owner companies plan to ask for were to eliminate thawing of permafrost soils a 30-year renewal. The original VSM design and maintain soil stability (Williams, 1986, Chap- represented a coordinated effort by the Alyeska ter 4). owners with strong oversight by the TAPS About 61,000 of the 78,000 VSMs are Federal Inspectors Office. That office relied equipped with pairs of thermosyphons (heat pipes), which were installed to remove heat from the permafrost by releasing it to the atmosphere. They are designed to operate between a range of temperatures in summer and winter and were installed mainly in areas of warm permafrost. Alyeska Pipeline Service Company’s Environ- mental and Technical Stipulation Compliance Assessment Document provided the geotechnical justification for the design mode for each of the 1000 individual design segments in the 800-mile pipeline. The pipeline includes 200 elevated segments, where the thermosyphon function is particularly important because local soils have high liquefaction potential. An assessment of the long-term performance of the TAPS heat pipes is provided by Sorensen et al. (2003). The Federal/State Joint Pipeline Office (JPO) has identified 22,000 VSMs as having possible problems caused by climate change along the pipeline route (JPO, 2001). It has also identified more than 50,000 of the heat pipes that have experienced some malfunction or blockage over the 25-year life of the TAPS. Some VSMs have required replacement. A thawing south-facing slope first identified in 1990 at the Squirrel Creek crossing resulted in one VSM tilting seven degrees by 1993. VSMs at this site were replaced in 2000. Other VSMs are being evaluated for replacement (Golder Associates, 2000). Proper functioning of the VSMs is critical to the future reliability of the TAPS. At present, neither Alyeska Pipeline Service Figure 16. Vertical support members (VSMs) along the Trans-Alaska Pipe- Company nor the JPO regard permafrost deg- line System. 34 Climate Change, Permafrost, and Impacts on Civil Infrastructure

upon the expertise of the U.S. Army Cold Environmental Effects, 2003, Chapter 6) and Regions Research and Engineering Laboratory close monitoring is critical. (CRREL) and the USGS for identification of soil and permafrost problems; continuing 3.4 Summary operations should incorporate similar cooperative efforts. A significant proportion of Alaska’s popula- In addition to the TAPS segments elevated tion and infrastructure is located in areas of on VSMs, soil stability in non-permafrost areas permafrost, much of which may become where the pipeline is buried may be affected. unstable under conditions of global warming. While there was no permafrost located imme- Although much of this infrastructure was diately adjacent to the buried pipeline, changes designed for permafrost, substantial retrofitting in freeze–thaw depth, water table location, and to accommodate warming conditions may be soil bearing capacity may cause degradation in necessary. In many instances designs are clearly downslope areas, river crossings, and other inadequate, and infrastructure could be severely areas. damaged by differential thaw settlement. The TAPS cannot be discussed without men- The problems presented by climate warm- tioning the large infrastructure on the North ing in Alaska, although substantial, are not Slope, which provides the oil to the pipeline. insurmountable. To achieve maximum effective- Literally tens of billions of dollars of construc- ness in an era of declining oil revenues and tion is responsible for drilling pads, production limited financial resources for both industry and installations, injection plants, pump stations, and government at all levels, a prevenient, well- hundreds of miles of feeder pipelines. Although informed, and coordinated response to the these facilities are located on the colder perma- effects of global warming on permafrost is frost north of the Brooks Range, which may essential. The last chapter of this report provides not be as susceptible to thawing as is the warmer a general prescription for the roles governmen- permafrost, their impacts have been substantial tal agencies can and should play in permafrost (Walker et al., 1987; Committee on Cumulative research. Chapter 4

FINDINGS AND AGENCY RECOMMENDATIONS

Members of the U.S. Arctic Research Com- ing of the role and behavior of frozen ground and mission Permafrost Task Force met in Salt Lake associated processes, dictates that permafrost City, Anchorage, San Francisco, and Seattle research should have equal weight with other between November 2001 and December 2003. components of the cryosphere in climate-change Discussions were also held with scientists, pri- research. The Task Force believes it is critical vate industry, the U.S. Permafrost Association, that programs such as SEARCH, ACIA, PACE, senior managers of federal agencies, and State ACD, Arctic-CHAMP, Land–Shelf Interac- of Alaska departmental personnel. An integra- tions, the Fourth International Polar Year, and tion of these meetings and discussions with the others have permafrost research as one of the background provided by Chapters 1 through 3 critical elements of their science plans. The of this report resulted in the following findings Task Force recommends that all responsible and recommendations. The entire report with funding agencies review their interdiscipli- recommendations has been reviewed by the nary Arctic programs to ensure that perma- Commissioners and five independent, outside frost research is appropriately integrated in reviewers. program planning and execution.

4.1 U.S. Federal Permafrost 4.1.2 Lack of a Visible U.S. Federal Research Programs Research Program The Task Force found no focused federal 4.1.1 Permafrost: Equal Attention research program dedicated to permafrost. The Despite publication of several reports speci- National Science Foundation funds investiga- fying needs and strategies (Committee on tors in a wide range of disciplines and, under Permafrost, 1974, 1975, 1976, 1983; Brown and the Office of Polar Programs (mostly through Hemming, 1980), permafrost research, both its Arctic System Science Program), makes basic and applied, has received less attention awards in permafrost science. The two within U.S. government research programs than components of GTN-P are examples of highly it warrants. This situation may in part result successful research programs that have received from a perception that permafrost is very slow recent support from NSF. Another good to respond to climate change. On the contrary, example is the development of a Permafrost permafrost has significant roles in climate Observatory at Barrow by the International change: as a record keeper of past tempera- Arctic Research Center, University of Alaska tures, as a translator of climate change through Fairbanks. In past decades, particularly during the effects of its degradation on ecosystems and the Cold War and the construction of the DEW human infrastructure, and as a facilitator through Line and the Trans-Alaska Pipeline, CRREL and its potential for release of sequestered carbon. USGS had viable and robust long-term research The importance of permafrost in the global sys- programs on permafrost science and engineer- tem, combined with our incomplete understanding. These once highly visible federal programs 36 Climate Change, Permafrost, and Impacts on Civil Infrastructure

no longer exist. The Task Force recommends same height above the ground surface using a that the USGS, because of its key responsi- standard radiation shield). Such sites should be bilities in Alaska, should develop a long-term linked via satellite to provide real-time data to permafrost research program with emphasis users. Further, a concerted effort should be on field programs. Recognizing DOD’s made to assess the degree to which instrumented responsibilities in the areas of contaminants sites are representative of the landscape. At on formerly used defense sites and future this scale, timely acquisition of current and his- military construction in Alaska, the Task torical remotely sensed imagery is essential. In Force recommends enhanced funding for this way, a standardized set of basic environ- permafrost research and continued develop- mental measurements, representative of a larger ment of permafrost expertise at CRREL. region, can be collected and incorporated into a spatially extensive data set that can serve the 4.2 Data Collection, Protocols, needs of the national and international cold- Monitoring, and Mapping regions science and engineering communities.

4.2.1 Standardized Collection of Basic 4.2.2 Measurement Protocols Environmental Parameters for Permafrost Monitoring Standardized collection of basic environ- A specific set of measurement protocols mental parameters is essential to all scientific and should be developed for monitoring permafrost engineering endeavors in cold regions. and closely related phenomena. The protocols Effectively designed and implemented monitor- should be established by the scientific and engi- ing programs and sampling strategies provide neering communities for the purpose of obtain- data that form the foundation upon which all ing appropriate measurements at appropriate efforts ultimately depend. Moreover, the data spatial and temporal frequencies and resolution. derived from such programs are invaluable for These protocols should cover the scale of modeling efforts (e.g., general circulation instrumentation, ranging from site to satellite. models). The Task Force recommends that Inherent in these protocols are the requisite the WMO GHOST (Global Hierarchical accuracy and precision of thermistors, optimal Observing Strategy) hierarchical monitoring depth of soil measurements, and requisite scheme discussed in Chapter 2 be imple- ancillary data. This effort should be coordinated mented in its current or a modified format in and integrated with the GTN-P to ensure permafrost monitoring programs. Effort should collection of data useful for global climate be made to support the instrumentation deemed observation (Burgess et al., 2000; GTN-P web necessary to collect basic data, in addition to site). Similarly, methods of monitoring active- the information collected for process-based field layer thickness and thaw subsidence should be studies. At the lowest level of instrumentation, integrated with those of ongoing international air, near-surface, and upper-permafrost temper- projects (e.g., CALM, PACE) following discus- ature measurements should be collected at sub- sion and any appropriate modification of those diurnal frequencies. Complete meteorological protocols currently in place. In all cases, effort instrumentation at the higher end of the spec- should be made to assess the spatial variability trum should include measurements of wind of thaw depth and soil temperature and to collect speed and direction, insolation, surface albedo, ancillary data. soil moisture, and snow cover thickness, and it should include a dense vertical array of thermistors 4.2.3 Permafrost Data Management extending from the soil surface, through the active Data collected by federally funded perma- layer, and deep into the underlying permafrost. frost projects should be archived in the Frozen The basic aspects of data collection at these Ground Data Center at NSIDC within sites should be standardized (e.g., all air tem- appropriate time periods. Details about data- perature measurements should be made at the collection sites and meteorological and ground Chapter 4. Findings and Agency Recommendations 37 measurements should be available in metadata regard to climate change. Federal and state files with standardized formats. Some data agencies and, potentially, the private sector would be processed in accordance with identi- should jointly fund this effort (USGS; Army fied and established user needs (e.g., modelers Corps of Engineers, Alaska District; Alaska and engineers may make better use of average State agencies; and industry). The evolving daily temperatures or accumulated degree-days Arctic Coastal Dynamics (ACD) program, a of freezing, thawing, heating, and cooling rather joint effort of the IASC and IPA, could also be than hourly air temperatures). Spatially inten- a vehicle for facilitating data collection and sive measurements, such as satellite imagery mapping of coastal erosion and flooding regimes. or thaw depths collected on a regular grid, A continuing research theme should be the should be available in a format conducive to integration of existing permafrost maps with generation of descriptive statistics and rapid elements of Arctic infrastructure, using GCMs mapping. Ultimately, these data will become part and GIS. These products should include new of an international cold regions environmental information on the distribution and properties of data directory with links to other databases. offshore and alpine permafrost.

4.2.4 NSIDC Frozen Ground Data Center 4.2.6 Measurement Technologies A recent initiative at the National Snow and and Remote Sensing Ice Data Center (NSIDC) in Boulder has been Typical measurements for the different to archive permafrost and seasonally frozen hierarchies of permafrost sites are provided in ground data (for example, borehole data, Arctic Section 2.3. Measurements range from probing Coastal Dynamics program data, and maps and the active layer once annually to observing soil soils data from Russia and China). These temperature approximately hourly; annual to activities are partially funded by the Interna- semi-annual permafrost temperatures have also tional Arctic Research Center at the University been taken at 100-m depths. A fully instrumented of Alaska Fairbanks. The data activities are an single site for examining temporal variability would outgrowth of the International Permafrost include measurements of soil temperature, soil Association’s data rescue program, the Global moisture, active-layer thickness, thaw settle- Geocryological Database. Long-term funding ment, and near-surface permafrost tempera- for the Frozen Ground Data Center is required. tures. Air temperature, wind speed, precipitation, Recognizing that NSIDC is funded primarily and snow depth are also high-priority measure- by NOAA, the Task Force strongly recom- ments. With the exception of soil moisture, off- mends that additional funding be provided the-shelf instrumentation can make these mea- by both NOAA and USGS to fully develop surements automatically and relatively and sustain the Frozen Ground Data Center inexpensively. Presently, data are typically (an estimated $300,000 annually is required recorded on a datalogger downloaded during for adequate support). an annual visit to the site. Retrieval of data by satellite uplink would mitigate the need for large 4.2.5 Baseline Permafrost Mapping data storage capacity on-site and would allow The Task Force recommends that U.S. and sites to be monitored in near-real time. A critical international funding be sought to update instrumentation issue that needs to be addressed the International Permafrost Association’s is the development of advanced technology for Circum-Arctic Map of Permafrost and Ground monitoring soil moisture. The Task Force rec- Ice Conditions (Brown et al., 1997), using the ommends support for the development of most recent international databases and instrumentation for sensors in cold-regions maps. In addition, the Task Force recom- terrain by NSF’s Office of Polar Programs mends the funding and production of a high- and Directorate of Engineering and by NASA. resolution permafrost map for Alaska, a crit- Satellite remote sensing offers the greatest ical requirement for the state’s future with opportunity for large-scale monitoring of the 38 Climate Change, Permafrost, and Impacts on Civil Infrastructure

state of ground. The capability of current tion of the air–surface–permafrost transfer sensors for permafrost monitoring needs to be function remains a significant problem, because fully evaluated and exploited, as the study of of non-linearity in the near-surface layer (air, permafrost by satellites has been a low-priority snow, vegetation) and because of numerous issue in the remote sensing community. The feedback effects. Continued basic research on Task Force recommends that NASA continue these processes is critical if a complete under- development of new satellite sensors opti- standing of arctic energy flows is to be achieved. mized for monitoring state of the surface, Carbon cycle considerations. Greenhouse temperature, moisture, and ground ice in gases (carbon dioxide and methane) released cold regions. A greater capability to detect from thawing permafrost into the atmosphere ground ice would have additional planetary could create a strong positive feedback in the applications. All remote sensing techniques will arctic system, and this topic is under investigation require thorough field validation. Until reliable at several sites. Counterbalancing this predic- permafrost sensors become available, methods tion, there may be increased arctic ecosystem that combine remotely sensed data with ground- plant productivity, which could enhance the based measurements and soil thermal modeling carbon sink (Kolchugina and Vinson, 1993). The should be developed and tested. Further, much carbon cycle in the nearshore zone of the Arctic can be inferred about permafrost from combin- Ocean has received less attention and requires ing digital elevation measurements (DEMs) with significant investigation. Key questions remain: other remotely sensed parameters such as those What is the major mechanism regulating the concerning snow cover and vegetation. How- distribution and associated rates of carbon trans- ever, the DEMs currently available for much of fer, transformation, and burial in the arctic land– Alaska are extremely coarse and sometimes shelf system? How do biogeochemical inaccurate, limiting their utility. The Task Force processes on the Arctic Ocean margins influ- recommends support for advanced studies ence the chemistry and biology of surface waters involving synthesis of remotely sensed data and associated fluxes of CO2 between the air– with other data sets, including model output. water (or air–ice) interface? Answers to such questions require much more research on the 4.2.7 Monitoring and Analysis Requirement state of offshore and onshore permafrost in the The Task Force recommends a new atmosphere–land–shelf system in the Arctic. approach (via federal legislation) for funding Hydrology and hydrogeology. Although the monitoring of cold-regions environments Arctic hydrology has received serious attention in which federal projects are planned. Fed- in many science planning documents, little eral agencies that fund all or portions of attention has been devoted to subsurface major public works (in excess of $1M in hydrologic and hydrogeologic processes. This cost) in Alaska should specify that 1% of is a critical omission because subsurface flow the project planning, design, and construc- and subsurface storage are extremely impor- tion costs for future Alaskan projects be tant in the arctic hydrological system and in the invested in monitoring in the vicinity of the arctic water cycle as a whole. Studies of perma- construction site. In this way climate change frost hydrogeology are practically nonexistent can be more adequately monitored and obser- in the U.S., a serious gap in research for the vations analyzed and mapped into the future. high Arctic and Subarctic. The Task Force recommends that NSF’s new arctic programs, 4.3 Basic Permafrost Research Arctic-CHAMP and Land–Shelf Interactions, fully incorporate permafrost hydrology and 4.3.1 Process Studies hydrogeology in their science plans. in Permafrost Research Permafrost degradation. Stratigraphic and Transfer functions: air–surface–perma- paleogeographic evidence indicates that permafrost, snow, vegetation. Quantitative estima- frost will degrade if recent climate warming Chapter 4. Findings and Agency Recommendations 39 continues. Degradation of ice-rich permafrost both modelers and permafrost researchers, and has been documented under contemporary con- continued cooperative research between the ditions in central Alaska and elsewhere two communities is a necessity. Funding of (Osterkamp and Romanovsky, 1999; modeling efforts for arctic and subarctic regions Osterkamp et al., 2000; Jorgenson et al., 2001). must require that permafrost be incorporated in Little is known, however, about specific the research plans. processes associated with the thawing of Another important issue related to GCMs is permafrost, either as a function of time or as a how well they can predict the extent, duration, three-dimensional process affecting the geom- and thickness of snow. Permafrost degradation etry of permafrost distribution over a wide spec- under a changing climate scenario is strongly trum of geographic scale. There is urgent need influenced by the regional snow cover. To date, to conduct theoretical and numerical studies and GCMs do not provide an adequate predictive additional field investigations to address these capability for snow. critical issues; stratigraphic and paleoclimatic Analytical models. Many methods have studies incorporating stable isotope dating should been proposed to calculate active-layer thick- be included, as has been done in the field of ness and mean annual permafrost surface tem- glaciology. peratures using simplified analytical solutions Geomorphic investigations. The study of (Pavlov, 1980; Zarling, 1987; Romanovsky and landforms and geomorphic processes is a criti- Osterkamp, 1995; Smith and Riseborough, cal component of permafrost science but has 1996). For work involving point locations where received little attention in Alaska in recent subsurface data are available, the importance decades. Process-based and modeling investi- and utility of analytical solutions is diminished. gations focused on the evolution of slopes and Numerical models are widely available for other geomorphic features are urgently needed. permafrost problems and can be used with some Particular attention should be given to how pro- confidence when adequate information about cesses interact over a spectrum of geographic climatic, boundary layer, and subsurface param- scale. Studies focused on landscape evolution eters is available. Serious problems arise, over extended periods are also critical and can however, when complex models are employed contribute to existing programs (e.g., SEARCH, in a spatial context, particularly when little is Arctic-CHAMP) concerned with hydrological known about the spatial variability of parame- and sediment budgets over extensive areas. ters important to geocryological investigations. Geomorphological studies should, where possi- In such cases, stochastic modeling (Anisimov ble, employ a systems approach that combines et al., 2002) or analytic procedures in a GIS expertise from closely related disciplines. environment (Nelson et al., 1997; Shiklomamov and Nelson, 1999; Klene et al., 2002) often yield 4.3.2 Permafrost Modeling results superior to complex, physically based Modeling is a powerful tool in permafrost models. Analytical equations can also be help- research. Although significant progress has been ful in providing insights into the physics of the achieved during the last three decades, the coupling between permafrost and the importance of permafrost in a global context atmosphere. However, these simple equations has been underestimated. Until recently, GCMs are presently limited in their usefulness because did not incorporate permafrost and permafrost- they do not include the effects of inhomogeneous related processes. The modeling community has active layers with multiple layers, variable begun to understand that unless permafrost and thermal properties, unfrozen water dynamics, permafrost-related processes are incorporated, and non-conductive heat flow. Deterministic there is little reason to expect that GCMs will models must be transformed to probabilistic produce physically reasonable results for the models if the risk of permafrost degradation is Arctic (Slater et. al., 1998a, b). Inclusion of to be assessed under a changing climate sce- permafrost in GCMs is a major challenge to nario (Bae and Vinson, 2001; Vinson and Bae, 40 Climate Change, Permafrost, and Impacts on Civil Infrastructure

2002). More research on refining analytical resolved. The Task Force recommends that models (both deterministic and probabilistic) for a denser network of environmental monitor- use in permafrost environments is a necessity. ing stations be funded by NOAA, USGS, USDA, and responsible state agencies for 4.4 Applied Permafrost Research Alaska. Such a network of monitoring stations, along with the application of GIS mapping 4.4.1 Synthesis for Cold-Regions methods, will allow improved procedures to be Engineering Applications developed for predicting permafrost behavior Scientific research programs are not neces- that can better account for natural variability sarily tailored to the needs of engineering and probabilistic considerations. practice and design criteria development. Predictions of frost effects and the behavior of 4.4.2 Cold-Regions Design frozen ground are highly empirical and are based Criteria Development on limited numbers of field and laboratory There is a significant requirement for a cold- investigations. Far-reaching assumptions are regions engineering database to enhance the necessary to arrive at any decisions regarding design, construction, and maintenance of infra- changes to the natural pattern of warming or structure. Existing environmental atlases of cooling of foundations for buildings, roads, rail- Alaska are nearly twenty years old. A new data- ways, or airstrips in a permafrost environment. base should take advantage of GIS technology Engineers tend to rely a great deal on the proven and include geotechnical information, such as performance of past construction as essential permafrost distribution, soil type, and soil prop- validations of analytical predictions. erties, as well as climatic information including In a period of accelerating global warming, air temperature and snow depth. The system the recent past provides only partial guidance should allow standard calculations for practical for predicting future permafrost conditions. engineering applications, such as freezing and Extrapolation of the recent air temperatures can thawing indices, active-layer thickness, and soil be misleading. The Task Force believes bearing capacity. There is also a need to estab- decisions regarding new infrastructure on lish a database or information clearinghouse on permafrost will be more credible if they con- existing cold-regions transportation infra- sider climate change, as predicted by global structure (design, construction, and operations). circulation models, weighed by associated Methods for site-specific forecasts of climate probabilities. change must be developed. A rational approach A history of seasonal temperature is repre- to developing design criteria using GCM results sented through freezing and thawing indices, the will perhaps be more affordable than applying annual sums of daily average temperatures an arbitrarily large factor of safety to conven- below or above freezing, respectively. Freezing tional design criteria. We cannot continue to treat and thawing indices are translated to corre- forecasts of future climate deterministically (i.e. sponding ground surface freezing and thawing linearly extrapolating a rate of temperature indices for general categories of ground surface change over a future time interval at a given types, e.g., snow, turf, sand, and gravel. The location) and must move to a more probabilistic transfer of atmospheric heat energy into lower approach. Adaptating conventional statistical layers of the soil is proportional to the soil thermal analyses of trends and extremes to apply GCM- conductivity, which varies with soil grain size, predicted accelerated change is a challenging dry density, water content, and water state topic for researchers. (frozen or unfrozen). More precise computa- tions of heat transfer are possible but impractical 4.4.2 Trans-Alaska Pipeline in all but carefully controlled research settings. System (TAPS) Alaskan records of air temperature are sparse, In its 2001 Comprehensive Monitoring and maps of soil characteristics are poorly Report (a series of three reports dealing with Chapter 4. Findings and Agency Recommendations 41

TAPS operations, construction, and operation), secretariat at the University of Alaska Fairbanks) the Joint Pipeline Office (JPO) of the U.S. and should be established early in this effort. the State of Alaska indicated a range of problems regarding changing permafrost. The 4.4.3 Contaminants in following conclusions were reached: Permafrost Environments • The warming trends could have some effect Past practice favored burial of contaminants on the foundations of the elevated portions in permafrost because it was assumed to be of the pipeline, some 423 miles with 78,000 impermeable and therefore a safe and effec- vertical support members (VSMs). tive method for isolating contaminated wastes. • More than 25,000 VSMs are currently Contaminants are mobile in the active layer, subject to movement. Of those VSMs hav- however, and some can even be mobile within ing heat pipes (because they are located in frozen ground. Moreover, when permafrost areas of warm permafrost), 84% have some thaws, the ground becomes permeable, allow- degree of blockage that could affect the ing contaminants to spread laterally and to reach structure’s load-bearing capacity. deeper unfrozen and frozen layers. The Arctic • A long-term maintenance and reconstruc- contains a significant number of contaminated tion program is necessary for the VSMs. sites; in Alaska DOD has responsibility for for- The pipeline owners and their operating con- merly used defense sites, some of which are sortium, Alyeska, have contracts underway to contaminated. To determine the extent of the determine the scope of the operating and main- problem, sites known to be contaminated must tenance program that will be necessary over be assessed individually, identifying the contam- the next 30 years, the period requested for a inants as well as the physical characteristics of right-of-way renewal. The current lease expires the site. The potential for diffusion of contami- in 2004 for both the federal and state rights of nants will require an estimate of the impact of way. regional climate warming on the specific sites. When the present lease was issued, scientific To develop models to predict the transport of and engineering decisions were based on the contaminants, the hydrological connections permafrost and climate regimes of the previous between the near-surface and deeper layers or three decades. Permafrost engineering appli- ground water systems must be established. cations were limited until World War II and Research is also required on the chemical reached their peak during the construction of interaction of contaminants with the thawed the DEW Line from 1948 to 1962. The exper- soils, as well as on such mitigation techniques tise of CRREL and the USGS was made avail- as bioremediation. CRREL is the logical federal able to the TAPS design team, which spent four laboratory for this research, and the University years working out the present design of the of Alaska (Fairbanks and Anchorage campuses) VSMs. The Task Force recommends that a has experienced research groups in this field. similar effort be made today that closely The Task Force recommends substantially coordinates the efforts of the TAPS and JPO increased federal funding for contaminants with a significantly upgraded federal research in cold regions by DOD, EPA, and research effort on permafrost. Linkages with NSF, as this research is deemed critical to the Arctic Climate Impact Assessment (with its the Nation’s cleanup effort in Alaska. 42 Climate Change, Permafrost, and Impacts on Civil Infrastructure

Federal Agency, State of Alaska, and National Research Council Recommendations

U.S. Geological Survey National Science Foundation (Department of the Interior) • Review all interdisciplinary arctic programs to ensure • Develop a long-term permafrost research program that permafrost research is appropriately integrated with emphasis on field work and monitoring of deep in program planning and execution. boreholes; formulate the program as a contribution to • Within the Office of Polar Programs, restructure the SEARCH. Glaciology program under the heading Cryosphere, • Adopt the WMO GHOST hierarchical monitoring which would include snow, ice, and permafrost. program for environmental data collection for new • Adopt hierarchical, spatially oriented monitoring boreholes and mapping. strategies (preferably variants of the WMO/GHOST • Jointly fund with NOAA the Frozen Ground Data approach) as appropriate for all arctic research Center at NSIDC. programs. • Participate in joint funding of a high-resolution perma- • Fund proposals for the development of instrumenta- frost map of Alaska. tion for sensors in cold regions (e.g., an autonomous • Fund (with NOAA, USDA, and state agencies) a soil moisture sensor) (Office of Polar Programs and denser network of environmental monitoring stations Directorate of Engineering). for Alaska. • Incorporate permafrost hydrology, hydrogeology, and • Provide technical expertise (on permafrost and other geomorphology in arctic programs such as Arctic- cold-regions issues) to the TAPS JPO during the right- CHAMP and SEARCH; incorporate permafrost of-way renewal process. research in global carbon programs. • Develop jointly with the Minerals Management • Increase support for research on permafrost-related Service a study of offshore undersea permafrost. geomorphic processes and terrain/landform analysis. • Expand stratigraphic investigations and mapping of Qua- • Increase support for geocryological hazards research ternary permafrost in Alaska and the contiguous states. at local, regional, and circumpolar scales. • Expand investigations of periglacial landforms and pro- • Increase funding for proposals dealing with research cesses (both contemporary and relict) in Alaska and on contaminants in cold regions. the contiguous states. • Support international permafrost activities, including conferences and workshops. U.S. Army Corps of Engineers • Integrate the use of the Permafrost National Test Site (Department of Defense) at Fairbanks into U.S. Arctic research logistics • Provide enhanced funding for permafrost research planning. and support the continued development of permafrost • Include permafrost research at the Barrow Global expertise at CRREL. Climate Change Research Facility. • Participate in joint funding of a high-resolution permafrost map of Alaska. National Aeronautics and Space Administration • Increase funding for research on contaminants in cold • Continue the development of satellite sensors regions at CRREL. optimized for monitoring the state of the surface, • Plan for climate change and permafrost degradation temperature, moisture, and ground ice in cold regions. at existing and new military facilities to be built in • Explicitly include geocryological applications in com- Alaska. petitive grants programs concerned with the use of • Rescue past agency data and contribute present and satellite remote sensing data. future data to national archives. • Include the development of frozen ground sensors in • Expand the role of the National Permafrost Test Site NASA contributions to SEARCH. [a node in the National Geotechnical Experimenta- • Support the Barrow Global Climate Change Research tion Sites (NGES) network] on Farmer’s Loop Road Facility as a satellite sensor validation site; use the outside Fairbanks. facility to ground-truth satellite frozen ground sensors. Chapter 4. Findings and Agency Recommendations 43

National Oceanic and Atmospheric Administration • Formalize and extend existing programs investigating (Department of Commerce) soil physics and ground temperature in Alaska, the • Jointly fund with USGS the Frozen Ground Data western cordillera of the contiguous states, and the Center at NSIDC. northern Appalachians. • Jointly fund with USGS, USDA, and the State of Alaska a denser network of environmental monitor- State of Alaska ing stations around Alaska. • Review the arctic engineering certification process • Adopt the WMO GHOST hierarchical monitoring for knowledge of permafrost under changing climate program for environmental data collection. conditions. • Seek federal support for test programs for non- Environmental Protection Agency standard pavements for roads and airport runways. • Increase funding for research on contaminants in cold • Review building codes with a view to near-term regions, and fully develop a program in Alaska. changes in the permafrost regime. • Make funding available for permafrost-related • Intensify and extend geological and geophysical hazards research, particularly in urban areas. investigations of permafrost and its role in Quaternary history by the Division of Geological and Geophysi- U.S. Forest Service cal Surveys (DGGS). (Department of Agriculture) • Survey community infrastructure located in perma- • Increase the number of soil moisture and tempera- frost environments, with specific emphasis on rural ture monitoring stations in Alaska. sewage and ground water systems. • Formalize and extend existing programs in soil physics and carbon sequestration. National Research Council (National Academies of Science and Engineering) U.S. Natural Resources Conservation Service • Have the Transportation Research Board (TRB), in (Department of Agriculture) cooperation with the Polar Research Board (PRB), • Refine and extend activities devoted to characteriz- develop a proposal for a study on the impacts of changing, classifying, and mapping cryosols in Alaska and ing permafrost on transportation systems in Alaska. the contiguous states. • Have the Polar Research Board (PRB) include glo- • Formalize and extend existing programs related to bal permafrost monitoring and research in the U.S.- carbon sequestration in tundra regions of Alaska and supported programs for the International Polar Year, the contiguous states. 2007–2008. References

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Most of the definitions given below were Degree-day taken from the Multi-Language Glossary of A derived unit of measurement used to Permafrost and Related Ground-Ice Terms express the departure of the mean temper- (van Everdingen, 1998). This source should be ature for a day from a given reference consulted for more extensive definitions. temperature. Also see freezing index and Updates, modifications, or new definitions are thawing index. indicated by inclusion of additional references. Depth of zero annual amplitude Active layer The distance from the ground surface The layer of ground subject to annual downward to the level beneath which there thawing and freezing in areas underlain by is practically no annual fluctuation in ground permafrost. temperature.

Active-layer detachment slide Excess ice Shallow landslides that develop in perma- The volume of ice in the ground that exceeds frost areas, involving reduction in effective the total pore volume that the ground would stress and strength at the contact between have under natural unfrozen conditions. a thawing overburden and underlying frozen material. Active-layer detachment slides Freeze–thaw cycle can occur in response to high seasonal air Freezing of material, followed by thawing. temperature, summer rainfall events, rapid The two fundamental frequencies involved melting of snowcover, or surface distur- are diurnal and annual. bances. See Lewkowicz (1992). Freezing index Active-layer thickness The cumulative number of degree-days The thickness of the layer of ground subject below 0oC for a given time period (usually to annual thawing and freezing in areas seasonal). underlain by permafrost (Also see thaw depth). See Nelson and Hinkel (2003). Frost action The process of alternate freezing and thaw- Alas ing of moisture in soil, rock, and other A large depression of the ground surface materials, and the resulting effects on produced by thawing of a large area (e.g., materials and on structures placed on or in > 1 ha) of very thick and exceedingly ice- the ground. rich permafrost. Frost creep Cryoturbation The net downslope displacement that (a)A collective term used to describe all soil occurs when a soil, during a freeze–thaw movements due to frost action. cycle, expands perpendicular to the ground (b)Irregular structures formed in earth surface and settles in a nearly vertical materials by frost penetration and frost direction. action processes, and characterized by folded, broken, and dislocated beds and lenses of unconsolidated deposits, included organic horizons, or bedrock. 58 Climate Change, Permafrost, and Impacts on Civil Infrastructure

Frost heave Ground ice The upward or outward movement of the A general term referring to all types of ice ground surface (or objects on or in the contained in freezing and frozen ground. ground) caused by the formation of ice in the soil. High-center polygon An ice-wedge polygon in which melting of Frost mound the surrounding ice wedges has left the Any mound-shaped landform produced by central area in a relatively elevated position. ground freezing, combined with accumulation of ground ice due to groundwater Ice lens movement or migration of soil moisture. Also A dominantly horizontal, lens-shaped body see Nelson et al. (1992). of ice of any dimension.

Frost penetration Ice segregation The movement of a freezing front into the The formation of discrete layers or lenses ground during freezing. of segregated ice in freezing mineral or organic soils, as a result of the migration Frost-susceptible soil and subsequent freezing of pore water. Subsurface earth materials in which segregated ice will form (causing frost heave) Ice wedge under the required conditions of moisture A massive, generally wedge-shaped body supply and temperature. with its apex pointing downward, composed of foliated or vertically banded, commonly Frozen ground white, ice. Soil or rock in which part or all of the pore water has turned into ice. Ice-wedge polygon A network of ice wedges defining the Gas hydrate boundaries of a geometric polygon in plan A special form of solid clathrate compound view. in which crystal lattice cages or chambers, consisting of host molecules, enclose guest Intrusive ice molecules. Ice formed from water injected into soils or rocks. Gelifluction The slow downslope flow of unfrozen earth Latent heat of fusion materials over a frozen substrate. Also see The amount of heat required to melt all ice solifluction. (or freeze all pore water) in a unit mass of soil or rock. For pure water this quantity is Geocryology 334 J g–1. The study of earth materials and processes o involving temperatures of 0 C or below. Low-center polygon An ice-wedge polygon in which thawing of Geothermal gradient ice-rich permafrost has left the central area The rate of temperature increase with depth in a relatively depressed position. below the ground surface. Glossary 59

Mass wasting (mass movement) Periglacial Downslope movement of soil or rock on or The conditions, processes, and landforms near the earth’s surface under the influence associated with cold, nonglacial environ- of gravity. ments, regardless of proximity to past or present glaciers. Massive ice A comprehensive term used to describe Permafrost large masses of ground ice, including ice Earth materials that remains continuously wedges, pingo ice, buried ice, and large ice at or below 0oC for at least two consecu- lenses. tive years.

Mean annual air temperature (MAAT) Permafrost, continuous Mean annual temperature of the air, mea- Regions in which permafrost occurs nearly sured at standard screen height above the everywhere beneath the exposed land ground surface. surface. At the circumpolar scale the term continuous permafrost zone refers to a Mean annual ground-surface temperature broad area, crudely conformable with (MAGST) latitude, in which permafrost is laterally con- Mean annual temperature at the surface of tinuous. See Nelson and Outcalt (1987). the ground. Permafrost, discontinuous Mean annual ground temperature (MAGT) Regions in which permafrost is laterally Mean annual temperature of the ground at discontinuous owing to heterogeneity of a specified depth. material properties, subsurface water, and surface cover. N-factor The ratio of the freezing or thawing index Permafrost, dry at the ground surface to that derived from Permafrost containing neither free water air temperature records. nor ice.

Palsas Permafrost, ice-rich Permafrost mounds ranging from about 0.5 Permafrost containing excess ice. to about 10 m in height and exceeding about 2 m in average diameter, comprising (1) Pingo aggradation forms and (2) degradation A perennial frost mound consisting of a core forms. The term “palsa” is a descriptive of massive ice produced primarily by injec- term to which an adjectival modifier prefix tion of water, and covered with soil and can be attached to indicate formative vegetation. processes. See Washburn (1983) and Nelson et al. (1992). Retrogressive thaw slump A slope failure resulting from thawing if ice- Patterned ground rich permafrost. A general term for any ground surface exhibiting a discernibly ordered, more or less Seasonally frozen ground symmetrical, morphological pattern of Ground that freezes and thaws annually. ground and, where present, vegetation. 60 Climate Change, Permafrost, and Impacts on Civil Infrastructure

Solifluction Thaw consolidation A general term referring to the slow down- Time-dependent compression resulting from slope flow of saturated unfrozen earth thawing of ice-rich frozen ground and sub- materials over an impermeable substrate sequent draining of excess water. (also see gelifluction). Thermal erosion Thermokarst terrain Erosion of ice-bearing permafrost by the Irregular topography resulting from the combined thermal and mechanical action melting of excess ground ice and subse- of moving water. quent thaw settlement. Thermal conductivity Thaw depth The quantity of heat that will flow through The instantaneous depth below the ground a unit area of a substance in unit time under surface to which seasonal thaw has pene- a unit temperature gradient. In permafrost trated (also see active-layer thickness). investigations thermal conductivity is usually See Nelson and Hinkel (2003). expressed in W m–1 oC–1.

Thaw lake Thermal offset A lake whose basin was formed or enlarged Temperature depression in the upper layer by thawing of frozen ground. See Hopkins of permafrost, resulting from the combined (1949) and Washburn (1980, p. 271). effects of seasonal differences of thermal conductivity and the operation of noncon- Thaw settlement ductive processes in the active layer. See Compression of the ground due to loss of Williams and Smith (1989) and Nelson et excess ground ice and attendant thaw con- al. (1985). solidation. Zero curtain effect Thawing index (DDT) Persistence of a nearly constant tempera- The cumulative number of degree-days ture very close to the freezing point of water above 0oC for a given time period (usually during annual freezing (and occasionally seasonal). thawing) of the active layer. See Outcalt et al. (1990). List of Acronyms

ACD EPA Arctic Coastal Dynamics (IASC) U.S. Environmental Protection Agency

ACIA FAO Arctic Climate Impact Assessment Food and Agriculture Organisation (of the United Nations) ADOT&PF Alaska Department of Transportation and FGDC Public Facilities Frozen Ground Data Center (NSIDC)

ALT GCOS active-layer thickness Global Climate Observing System

ARCSS GCM Arctic System Science program (NSF/ general circulation model (or global climate OPP) model)

Arctic-CHAMP GHOST Community-wide Hydrological Analysis and Global Hierarchical Observational Strategy Monitoring Program (U.S. National Science (WMO) Foundation initiative) GIS BEO geographic information systems (or geo- Barrow Environmental Observatory graphic information science)

CALM GSC Circumpolar Active Layer Monitoring Geological Survey of Canada program GTN-P CEON Global Terrestrial Network for Permafrost Circumarctic Environmental Observatories Network GTOS Global Terrestrial Observing System CRREL Cold Regions Research and Engineering IASC Laboratory (U.S. Army Corps of Engi- International Arctic Science Committee neers) ICSU DGGS International Council of Scientific Unions Division of Geological and Geophysical Surveys (Alaska Department of Natural IPA Resources) International Permafrost Association

DOD IPCC U.S. Department of Defense Intergovernmental Panel on Climate Change 62 Climate Change, Permafrost, and Impacts on Civil Infrastructure

IPY SEARCH International Polar Year Study of Environmental Arctic Change (U.S. federal government multiagency JPO initiative) Joint Pipeline Office (U.S. federal and State of Alaska) TAPS Trans-Alaska Pipeline System LTER U.S. Long Term Ecological Research TDR Network time-domain reflectometry

MAAT TEMS mean annual air temperature Terrestrial Ecosystem Monitoring Sites network MAGST mean annual ground surface temperature TOPC Terrestrial Observational Panel for Climate MAGT mean annual ground temperature UAF University of Alaska Fairbanks NASA U.S. National Aeronautics and Space UNEP Administration United Nations Environment Programme

NOAA UNESCO U.S. National Oceanic and Atmospheric United Nations Educational, Scientific and Administration Cultural Organization

NRCS USACE U.S. Natural Resources Conservation U.S. Army Corps of Engineers Service (USDA) USDA NSF U.S. Department of Agriculture U.S. National Science Foundation USPA NSIDC U.S. Permafrost Association U.S. National Snow and Ice Data Center (Boulder, Colorado) USARC U.S. Arctic Research Commission OPP Office of Polar Programs (U.S. National USGS Science Foundation) U.S. Geological Survey

PACE VSM Permafrost and Climate in Europe program vertical support member

WMO World Meteorological Organization UNITED STATES ARCTIC RESEARCH COMMISSION

The U.S. Arctic Research Commission (USARC) was created by the Arctic Research and Policy Act of 1984 (as amended in November 1990). The Commission, whose seven members are appointed by the President of the United States, assesses national needs for arctic research and recommends to the President and the U.S. Congress research policies and priorities that form the basis for a national arctic research plan. Other key USARC functions include facilitating cooperation in arctic research between federal, state, and local governments; recommending improvements in arctic research logistics; recommending areas for enhanced international scientific cooperation in the Arctic; cooperating with the Governor of Alaska in formulating arctic research policy; and con- ducting special studies such as Climate Change, Permafrost, and Impacts on Civil Infrastructure. USARC biennially submits a strategic document, Goals and Objec- tives for Arctic Research, to the Interagency Arctic Research Policy Committee for its use in revising a national five-year Arctic Research Plan. The Commission normally meets four times annually (at least once each year in Alaska) to hear invited and public testimony on all facets of Arctic research. The USARC staff has offices at 4350 North Fairfax Drive, Suite 510, Arlington, Virginia 22203, and 420 L Street, Suite 315, Anchor- age, Alaska 99501.

USARC COMMISSIONERS (DECEMBER 2003) George B. Newton, Jr. John R. Roderick Fairfax, Virginia (Chair) Anchorage, Alaska

Mary Jane Fate Susan F. Sugai, Ph.D. Fairbanks, Alaska Fairbanks, Alaska

John F. Hobbie, Ph.D. Mead Treadwell Woods Hole, Massachusetts Anchorage, Alaska

Duane H. Laible, PE Rita R. Colwell, Ph.D. Seattle, Washington Director, National Science Foundation (ex officio)

Back Cover: South-facing view of the Trans-Alaska pipeline near Sukakpak Mountain, southern Brooks Range foothills. This area is in the zone of discontinuous permafrost. Nearly 80% of the Trans-Alaska pipeline lies within the state’s permafrost regions (see Figure 15). Photo by F.E. Nelson, October 1982.