Climate Change, Permafrost, and

Impacts on Civil Infrastructure

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 Hemisphere; 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 citzens 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 Committee 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

Professor of Geography

University of Cincinnati

Dr. Frederick E. Nelson

Professor of Geography

University of Delaware

Walter Parker

Former Commissioner, U.S. Arctic

Research Commission

Parker Associates, Anchorage

Dr. Vladimir Romanovsky

Associate Professor

Geophysical Institute

University of Alaska Fairbanks

Dr. Orson Smith

Professor of Engineering

University of Alaska Anchorage

Walter Tucker

Geophysicist, U.S. Army Cold Regions

Research and Engineering Laboratory

Dr. Ted Vinson

Professor of Geotechnical Engineering

Oregon State University

Dr. Lawson W. Brigham

Deputy Executive Director

U.S. Arctic Research Commission
ii

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.
Acknowledgments

Lead Authors and Editors

Dr. David M. Cole

U.S. Army Cold Regions Research

and Engineering Laboratory

Anna E. Klene

University of Montana

Dr. Frederick E. Nelson

University of Delaware

Dr. Lawson W. Brigham

U.S. Arctic Research Commission

Contributing Authors

Dr. Kenneth M. Hinkel

University of Cincinnati

Walter Parker

Parker Associates, Anchorage

Dr. Vladimir E. Romanovsky

Geophysical Institute

University of Alaska Fairbanks

Dr. Nikolay I. Shiklomanov

University of Delaware

Dr. Orson Smith

University of Alaska Anchorage

Walter Tucker

U.S. Army Cold Regions Research

and Engineering Laboratory

Dr. Ted Vinson

Oregon State University

Contributors

William Lee

University of Alaska Anchorage

Amanda Saxton

U.S. Arctic Research Commission

iii
iv

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.
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
1.1 Introduction

Climate-change scenarios indicate that humancaused, or anthropogenic, warming will be

most pronounced in the high latitudes. Empirical evidence strongly indicates that impacts

related to climate warming are well underway

in the polar regions (Hansen et al., 1998; Morison et al., 2000; Serreze et al., 2000; Smith et

al., 2002). These involve air temperature (Pavlov, 1997; Moritz et al., 2002), vegetation

(Myneni et al., 1997; Sturm et al., 2001), sea

ice (Bjorgo et al. 1997), the cumulative mass

balance of small glaciers (Dyurgerov and Meier,

1997; Serreze et al., 2000; Arendt et al., 2002),

ice sheets and shelves (Vaughan et al., 2001;

British Antarctic Survey, 2002; Rignot and

Thomas, 2002), and ground temperature

(Lachenbruch and Marshall, 1986; Majorowicz

and Skinner, 1997).

Many of the potential environmental and

socioeconomic impacts of global warming in the

high northern latitudes are associated with

permafrost, or perennially frozen ground. The

effects of climatic warming on permafrost and

the seasonally thawed layer above it (the active

layer) can severely disrupt ecosystems and

human infrastructure and intensify global warming (Brown and Andrews, 1982; Nelson et al.,

1993; Fitzharris et al., 1996; Jorgenson et al.,

2001). Until recently, however, permafrost has

received far less attention in scientific reviews

and media publications than other cryospheric

phenomena affected by global change (Nelson

et al., 2002).

Throughout most of its history, permafrost

science in western countries was idiosyncratic,

performed by individuals or small groups of

Chapter 1

PERMAFROST AND ITS ROLE IN THE ARCTIC

researchers, and not well integrated with other

branches of cold regions research. Owing to

the importance of permafrost for development

over much of its territory, the situation in the

former Soviet Union was distinctly different, with

a large institute in Siberia and departments in

the larger and more prestigious universities

devoted exclusively to permafrost research.

Several factors converged in the late 1980s

and early 1990s to integrate permafrost research

into the larger spheres of international, systems,

and global-change science:

• Easing of Cold-War tensions facilitated

interactions between Soviet and western

scientists. Conferences held in Leningrad

(Kotlyakov and Sokolov, 1990), Yamburg,

Siberia (Tsibulsky, 1990), and Fairbanks

(Weller and Wilson, 1990) during the late

1980s and early 1990s were instrumental

in achieving international agreements.

• Publicity about the impacts of climate

warming in the polar regions followed several decades of unprecedented resource

development in the Arctic and raised concerns about the stability of the associated

infrastructure (Vinson and Hayley, 1990).

• The global nature of climate change made

apparent the need for widespread cooperation, both within the permafrost research

community and between permafrost

researchers and those engaged in other

branches of science (Tegart et al., 1990).

• Permafrost scientists became increasingly

aware of the benefits accruing from the

development of data archives and free

exchange of information (Barry, 1988; Barry

and Brennan, 1993). Moreover, the increasingly integrated nature of arctic science
demands widespread cooperation and collaboration. Some funding agencies, such as

the U.S. National Science Foundation, now

require, as a condition of funding, that data

be made accessible to all interested parties.

U.S. scientists have made major contributions to the study of frozen ground (geocryology), particularly since World War II. Useful

English-language reviews, many with emphasis on Alaska, have been provided by Muller

(1947), Black (1950), Terzaghi (1952), Stearns

(1966), Ives (1974), Washburn (1980), Andersland and Ladanyi (1994), Davis (2001), and

Hallet et al. (2004). Péwé (1983a) reviewed

the distribution of permafrost in the cordillera

of the western U.S.; Walegur and Nelson (2003)

discussed its occurrence in the northern Appalachians. Péwé (1983c) outlined the distribution of permafrost and associated landforms in

the U.S. during the last continental glaciation.

Permafrost science employs a complex and

occasionally confusing lexicon derived from

several languages and scientific disciplines. A

brief Glossary and a List of Acronyms at the

end of this document provide assistance for nav2 Climate Change, Permafrost, and Impacts on Infrastructure

Figure 1. 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.

The Ground Temperature Profile
Chapter 1. Permafrost and its Role in the Arctic 3

igating unfamiliar terminology. A more comprehensive glossary, published under the auspices

of the International Permafrost Association

(IPA), is readily available (van Everdingen,

1998).

1.2 Background and Concepts

1.2.1 Thermal Regime

Two classes of frozen ground are generally

distinguished: seasonally frozen ground, which

freezes and thaws on an annual basis, and

perennially frozen ground (permafrost),

defined as any subsurface material that remains

at or below 0oC continuously for at least two

consecutive years. The term permafrost is

applied without regard to material composition,

phase of water substance, or cementation.

Permafrost can be extensive in areas where

the mean annual temperature at the ground surface is below freezing. Because the temperature at the surface and the temperature in the

air often differ substantially (Klene et al., 2001),

and because of differences in the thermal conductivity of many soils in the frozen and unfrozen states (the thermal offset), permafrost can

exist for extended periods at locations with mean

annual air temperatures above 0oC (Goodrich,

1982). Climate statistics do not, therefore, provide a reliable guide to the details of permafrost

distribution. Although ultimately a climatically

determined phenomenon, the presence or

absence of permafrost is strongly influenced by

local factors, including microclimatic variations,

circulation of ground water, the type of vegetation cover, and the thermal properties of subsurface materials.

The range of temperatures experienced

annually at the ground surface in typical permafrost terrain decreases with depth, down to a

level at which only minute annual temperature

variation occurs, termed the damping depth or

level of zero annual amplitude. The active

layer above permafrost often experiences complex heat-transfer processes (Hinkel et al., 1997;

Kane et al., 2001). Below the permafrost

table—the upper limit of material that experiences a maximum annual temperature of 0oC—

heat transfer occurs largely by conduction. In

situations where, unlike Figure 1, the bottom of

the active layer is not in direct contact with the

top of the permafrost, the permafrost is a relic

of a past colder interval and may be substantially out of equilibrium with the contemporary

climate.

1.2.2 Landforms

Many distinctive landforms exist in permafrost regions, although only some unambiguously

indicate the presence of permafrost. Surface

features formed under cold, nonglacial conditions are known as periglacial landforms

(Washburn, 1980; French, 1996) (Fig. 2). One

periglacial feature that serves as a good indicator of the presence of permafrost is ice

wedges—vertical ice inclusions created when

water produced from melting snow seeps into

cracks formed in fine-grained sediments during

severe cold-weather events earlier in winter.

Repeated many times over centuries or millennia, this process produces tapered wedges of

foliated ice more than a meter wide near the

surface and extending several meters or more

into the ground. Viewed from the air, networks

of ice wedges form striking polygonal patterns

over extensive areas of the Arctic (Lachenbruch, 1962, 1966). Other landforms diagnostic

of the presence of permafrost are pingos—

ice-cored hills frequently over 10 m in height

that can form when freezing fronts encroach

from several directions on saturated sediments

remaining after drainage of a deep lake

(Mackay, 1998). Palsas—smaller, moundshaped forms often found in subarctic peatlands—can form through a variety of mechanisms (Nelson et al., 1992).

Other periglacial landforms occur frequently

in association with permafrost but are not necessarily diagnostic of its presence. When

ice-rich permafrost or another impermeable

layer prevents infiltration of water, the soil on a

hillside may become vulnerable to a slow, flowlike process known as solifluction, giving rise

to a network of lobes and terraces that impart a

crenulated or festooned appearance to the slope.

Other small landforms frequently encountered

in subpolar and polar regions, collectively

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.

Figure 2. Periglacial landforms often associated with permafrost.

d. Large-diameter sorted patterned ground, Cathedral

Massif, northwestern British Columbia.
Chapter 1. Permafrost and its Role in the Arctic 5

hummocks and networks of striking geometric

forms arranged into circles, polygons, or stripes

of alternating coarse- and fine-grained sediment.

1.2.3 Permafrost Distribution

The permafrost regions occupy approximately 24% of the terrestrial surface of the

Northern Hemisphere (Brown et al., 1997;

Zhang et al., 1999, 2003). Substantial areas of

subsea permafrost also occur around the land

margins of the Arctic Ocean, much of it ice

rich (Brown et al., 1997; Danilov et al., 1998).

The distribution of offshore permafrost is not

well known, and new occurrences are found

frequently. As shown in Figure 3, the distribution of permafrost is often classified on the basis

of its lateral continuity. In the Northern Hemisphere 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

concentric zones that conform crudely to the

parallels of latitude (Fig. 4). Southward deviations in the extent of permafrost in Siberia and

central Canada are a response to lower mean

annual temperatures in the continental interiors.

In the zone of continuous permafrost,

perennially frozen ground underlies most locations, the primary exception being under large

bodies of water that do not freeze to the bottom

annually. In the discontinuous zone, permafrost may be widespread, but a substantial proportion of the land surface can be underlain by

seasonally frozen ground, owing to variations in

such local factors as vegetation cover, snow

depth, and the physical properties of subsurface materials. Some authors also refer to a

zone in which permafrost is sporadic, occurring as isolated patches that reflect combinations of local factors favorable to its formation

and maintenance. Because the thermal properties of peat are conducive to the existence of

frozen ground, subarctic bogs are the primary

locations of permafrost in southerly parts of the

subarctic lowlands (Zoltai, 1971; Beilman and

Robinson, 2003). In the Southern Hemisphere,

permafrost occurs in ice-free areas of the Antarctic continent and in some of the subantarctic

islands (Bockheim, 1995). Permafrost is also

extensive in such midlatitude mountain ranges

as the Rockies, Andes, Alps, and Himalayas, a

response to progressively lower mean annual

temperatures at higher elevations. Given sufficient altitude and favorable local conditions,

patches of permafrost can exist even in the subtropics, such as in the crater of Mauna Kea

(4140 m above sea level) on the island of Hawaii

(Woodcock, 1974).

The thickness of permafrost is determined

by the mean annual temperature at the ground

surface, the thermal properties of the substrate,

and the amount of heat flowing from the earth’s

interior. Permafrost thicknesses range from very

thin layers only a few centimeters thick to about

1500 m in unglaciated areas of Siberia (Washburn, 1980). In general, the thickness of lowland

permafrost increases steadily with increasing

latitude.

1.2.4 Ground Ice and Thermokarst

Although the presence of ice is not a criterion

in the definition of permafrost, ground ice is

responsible for many of the distinctive features

and problems in permafrost regions. Ice can

occur within permafrost as small individual

crystals within soil pores, as lenses of nearly

pure ice parallel to the ground surface, and as

variously shaped intrusive masses formed when

water is injected into soil or rock and subseFigure 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,

on north-facing slopes.

At average annual temperatures around –5°C,

permafrost in Alaska is

essentially continuous,

and in northern Alaska

it extends to depths of

over 400 m, although

local unfrozen zones

(taliks) may exist

beneath large rivers and

lakes. The active layer

can be quite thick in the

sporadic permafrost

zone, and it decreases in

thickness with latitude,

although local factors

can make it highly variable (Nelson et al.,

1999). Near the coast of

the Arctic Ocean the

active layer reaches a

maximum mean thickness of only about 60 cm

in mid- to late August.
Chapter 1. Permafrost and its Role in the Arctic 7

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).]

quently frozen. The origin and morphology of

ground ice are varied (Mackay, 1972), ranging

from thick layers of buried glacier ice, through

horizontally oriented ice lenses formed by the

migration of moisture to freezing fronts (segregation ice), to the distinctive polygonal networks

of vertical veins known as ice wedges. If their

thermal stability is preserved, perennially frozen

ice-bonded sediments can have considerable

bearing capacity and are often an integral part

of engineering design in cold regions (Andersland and Ladanyi, 1994; Yershov, 1998). Figure

5 shows the generalized distribution of ground

ice in the Northern Hemisphere. A digital database on ground ice is under development at

Moscow State University (Streletskaya et al.,

2003).

Changes in the thickness and geographical

extent of permafrost have considerable potential for disrupting human activities if substantial
8 Climate Change, Permafrost, and Impacts on Civil Infrastructure

amounts of ground ice are present. Because

the volume is reduced when ice melts and

because pore water is squeezed out during consolidation, thawing of ice-rich sediments leads

to subsidence of the overlying ground surface,

often resulting in deformation of an initially level

surface into irregular terrain with substantial

local relief. By analogy with terrain developed

by chemical dissolution of bedrock in areas

underlain extensively by limestone, the irregular

surface created by thawing of ice-rich permafrost is known as thermokarst terrain.

Thermokarst subsidence occurs when the

energy balance at the earth’s surface is modified such that heat flux to subsurface layers

increases. The process occurs over a wide

spectrum of geographical scale, ranging from

highly localized disturbances associated with the

influence of individual structures to depressions

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;

Mackay, 1970). Similarly, wave action in areas

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 (Claridge 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

land was developed. A controlled experiment

at the Permafrost National Test Site near Fairbanks, Alaska, caused the permafrost table to

Thickening of the active layer has two immediate effects. First,

decomposed plant material frozen in the upper permafrost thaws,

exposing the carbon to microbial decomposition, which can release

carbon dioxide and methane to the atmosphere. Second, the ice in

the upper permafrost is converted to water. In coarse materials

such as sand and gravel, this is not necessarily a problem. However, fine-grained sediments often contain excess ice in the form

of lenses, veins, and wedges. When ice-rich permafrost thaws, the

ground surface subsides; this downward displacement of the ground

surface is termed thaw settlement (Fig. 6). Typically, thaw settlement does not occur uniformly over space, yielding a chaotic surface with small hills and wet depressions known as thermokarst

terrain; this is particularly common in areas underlain by ice wedges

(Fig. 7). When thermokarst occurs beneath a road, house, pipeline,

or airfield, the structural integrity is threatened. If thermokarst

occurs in response to regional warming, large areas can subside

and, if near the coast, can be inundated by encroaching seas.

Thermokarst and Ground Subsidence

Figure 6. Thaw settlement, which develops when icerich permafrost thaws and the ground surface subsides.

Figure 7. High-centered polygons near Prudhoe Bay,

Alaska. This form of thermokarst terrain develops

through ablation of underlying ice wedges.
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-

year period, simply by removing the insulating

layer of vegetation (Linell, 1973). Even trampling can trigger thermokarst (Mackay, 1970),

so agencies regulating tourism in the Arctic

(Johnston, 1997) will have to thoroughly assess

the relative merits of developing concentrated

traffic through systems of foot trails or encouraging more diffuse patterns of use. Developmental encroachment on lands traditionally used

to support herbivores may increase herd densities to such an extent that overgrazing could

induce widespread thaw settlement (Forbes,

1999). Brown (1997) provided a comprehensive review of a wide range of anthropogenic

disturbances affecting permafrost terrain.

1.3 Effects on Civil Infrastructure

Thermokarst can have severe effects on

engineered structures, in many cases rendering

them unusable. Because of its potential for

settlement, thawing of ice-rich permafrost constitutes a significant environmental hazard in

high-latitude regions, particularly in the context

of climatic change. Although hazards related to

permafrost have been discussed in specialist literature and textbooks (e.g., Brown and Grave,

1979; Péwé, 1983b; Williams, 1986; Woo et al.,

1992; Andersland and Ladanyi, 1994; Koster

and Judge, 1994; Yershov, 1998; Dyke and

Brooks, 2000; Davis, 2001), they are given scant

attention in most English-language texts focused

on natural hazards (e.g., Bryant, 1991; Coch,

1995). Much of the literature treating social

science and policy issues in the polar regions

(e.g., Peterson and Johnson, 1995; Brun et al.,

1997) also fails to adequately consider issues

related to permafrost.

Although the permafrost regions are not

densely populated, their economic importance

has increased substantially in recent decades

because of the abundant natural resources in

the north circumpolar region and improved methods of extraction and transportation to population centers. Economic development has brought

expansion of the human infrastructure: hydrocarbon extraction facilities, transportation networks, communication lines, industrial projects,

civil facilities, and engineering maintenance systems have all increased substantially in recent

decades. Rapid and extensive development has

had large costs, however, in both environmental and human terms (e.g., Williams, 1986; Smith

and McCarter, 1997), and these could be

aggravated severely by the effects of global

warming on permafrost.

Construction in permafrost regions requires

special techniques at locations where the terrain

contains ice in excess of that within soil pores.

Prior to about 1970, many projects in northern

Alaska and elsewhere disturbed the surface significantly, triggering thermokarst processes and

resulting in severe subsidence of the ground

surface, disruption of local drainage patterns,

and in some cases destruction of the engineered

works themselves. The linear scar in Figure 8e

marks the route of a winter road constructed in

1968-69 by bulldozing the tundra vegetation and

a thin layer of soil (Anonymous, 1970). This

disturbance altered the energy regime at the

ground surface, leading to thaw of the underlying ice-rich permafrost and subsidence of up to

2 m along the road (Nelson and Outcalt, 1982),

which became unusable several years after

construction.

Environmental restrictions in North America,

based on scientific knowledge about permafrost,

now regulate construction activities to minimize

their impacts on terrain containing excess ice.

The Trans-Alaska Pipeline, which traverses

1300 km from Prudhoe Bay on the Arctic

coastal plain to Valdez on Prince William Sound

near the Gulf of Alaska, carries oil at temperatures above 60oC. To prevent the development

of thermokarst and severe damage to the pipe,

the line is elevated where surveys indicated the

presence of excess ice. To counteract conduction of heat into the ground, many of the pipeline’s vertical supports are equipped with heat

pipes that cool the permafrost in winter, lowering the mean annual ground temperature and

preventing thawing during summer. In several

short sections of ice-rich terrain where local

above-ground conditions required burial of the

line, the pipe is enclosed in thick insulation and

refrigerated.

Other unusual engineering techniques devised
Chapter 1. Permafrost and its Role in the Arctic 11

for ice-rich permafrost include constructing

heated buildings on piles, which allows air to

circulate beneath the structures and prevents

conduction of heat to the subsurface. Roads,

airfields, and building complexes are frequently

situated atop thick gravel pads or other insulating materials. In relatively large settlements such

as Barrow, water and sewage are transported

in insulated, elevated pipes known as “utilidors”

(Fig. 9).

Figure 9. Utilidor in

Barrow, Alaska.
12 Climate Change, Permafrost, and Impacts on Civil Infrastructure
2.1 General Considerations

Climate change is one of the most pressing

issues facing science, governmental bodies, and,

indeed, human occupation of the earth. Because

of the extreme temperature sensitivity of cryospheric phenomena (snow, ice, frozen ground),

the world’s cold regions are and will continue

to be heavily impacted by climate warming.

Moreover, climate models indicate that warming will be particularly acute in the polar regions,

exacerbating these impacts and broadening their

geographic distribution. Changes involving

permafrost are likely to be as profound. Owing

to its multivariate role in climate change, its

potential impact on human activities, and its

widespread distribution, permafrost is among the

most important of cryospheric phenomena.

Recognition of the importance of permafrost

in global-change research, although slow in

developing, has become widespread in recent

years (e.g., McCarthy et al., 2001; Goldman,

2002; Hardy, 2003). Because permafrost is

highly susceptible to long-term warming, it has

been designated a “geoindicator,” to be used as

a primary tool for monitoring and assessing

environmental change (Berger and Iams, 1996).

This chapter outlines the role of permafrost in

global-change studies and describes several

national and international programs designed to

monitor geocryological changes and ameliorate

their impacts on human communities.

2.2 Permafrost and Global Change

Despite implications contained in the term

“permafrost,” perennially frozen ground is not

permanent. Permafrost was more widespread

during past episodes of continental glaciation.

Evidence for the former existence of permafrost, including ice-wedge casts and pingo scars,

has been found in areas of North America and

Eurasia now far removed from current permafrost regions. Detailed environmental reconstructions in which permafrost is a critical

paleogeographical indicator have been produced for Eurasia (e.g., Ballantyne and Harris,

1994; Velichko 1984). Although the former

extent of permafrost in North America is not as

well known, evidence that it existed during colder

intervals is scattered along the glacial border

from New Jersey to Washington state (Péwé,

1983c).

Abundant geological evidence also exists that

widespread thermokarst terrain developed in

response to past intervals of climatic warming.

In parts of the unglaciated lowlands of the central Sakha Republic (Yakutia) in Siberia, nearly

half of the Pleistocene-age surface has been

affected by development of alases, steep-sided

thermokarst depressions as much as 20–40 m

deep and occupying areas of 25 km2 or more

(Soloviev, 1973; Koutaniemi, 1985; French,

1996). Kachurin (1962), Czudek and Demek

(1970), and Romanovskii et al. (2000) attributed

the development of these Siberian alases to warm

intervals during the Holocene. In arctic parts of

North America, thaw unconformities (Burn,

1997), sedimentary evidence (Murton, 2001),

and extensive degradation of ice-cored terrain

(Harry et al., 1988) attest to periods in which

widespread, climatically induced thermokarst

developed. Global warming is likely to trigger a

new episode of widespread thermokarst develChapter 2

FUTURE CLIMATE CHANGE AND

CURRENT RESEARCH INITIATIVES
14 Climate Change, Permafrost, and Impacts on Civil Infrastructure

opment, with serious consequences for a large

proportion of the engineered works constructed

in the permafrost regions during the twentieth

century.

Permafrost plays three important roles in the

context of climatic change (Nelson et al., 1993;

Anisimov et al., 2001): as a record keeper by

functioning as a temperature archive; as a

translator of climate change through subsidence and related impacts; and as a facilitator

of further change through its impact on the

global carbon cycle. These roles are discussed

briefly in subsequent sections of this chapter

and are treated in more detail in Nelson et al.

(1993), Anisimov et al. (2001), and Serreze et

al. (2000).

2.2.1 Record Keeper: Permafrost

as a Temperature Archive

Permafrost is a product of cold climates and

is common in high-latitude and high-elevation

environments. Air temperature, the most influential parameter, determines the existence of

permafrost, as well as its stability. Although the

mean annual air temperature can be used as a

very general indicator of the presence of permafrost, other factors are involved in determining

its thickness, including substrate composition,

thermal evolution, and groundwater distribution.

The thickness, thermal properties, and duration of the snow cover exert a profound influence on permafrost (Brown and Péwé, 1973;

Smith, 1975; Hinzman et al., 1991; Romanovsky

and Osterkamp, 1995; Zhang et al., 1997; Burn,

1998; Hinkel et al., 2003a). At sites underlain

by permafrost in Alaska, the mean annual ground

surface temperature is commonly 3–6oC higher

than the mean annual air temperature. At sites

without permafrost, this difference can be even

larger, reaching 7–8oC in some years.

Despite subzero mean annual air temperatures, boreal areas of central Alaska may

experience mean annual ground surface temperatures above 0oC, owing to the insulating

effect of low-density snow cover. Nonetheless,

permafrost may exist at such locations because

of a thermal offset attributable to differences

in the thermal properties of the substrate in the

frozen and unfrozen states (Kudryavtsev et al.,

1974; Goodrich, 1978, 1982; Burn and Smith,

1988; Romanovsky and Osterkamp, 1995, 1997,

2000). This situation is common in peatlands,

which often form the southernmost occurrences

of subarctic permafrost (Zoltai, 1971). In a dry,

unfrozen state, peat is an extremely efficient

thermal insulator. When saturated and frozen,

however, its thermal conductivity approaches

that of pure ice. In such a situation, frost penetration in winter exceeds the depth of summer

thaw, and permafrost can form or persist,

despite mean annual air temperatures that would

otherwise preclude its existence.

Permafrost records temperature changes and

other proxy information about environmental

changes (Lachenbruch and Marshall, 1986;

Burn, 1997; Murton 2001). Because the transfer of heat in thick permafrost occurs primarily

by conduction, it acts as a low-pass filter and

has a “memory” of past temperatures. Through

the use of precision sensors, temperature trends

spanning a century or more can be recorded in

thick permafrost (Lachenbruch and Marshall,

1986; Clow et al., 1998; Osterkamp et al., 1998a,

b; Taylor and Burgess, 1998; Romanovsky et

al., 2003).

The U.S. Geological Survey (USGS) has

measured permafrost temperatures from deep

boreholes in northern Alaska since the 1940s.

Typically, this entails lowering a precision resistance thermistor down the access hole and

obtaining a highly accurate and precise temperature measurement at known, closely spaced

depths down the borehole. Analysis of these

data through the mid-1980s indicates that

permafrost on Alaska’s North Slope has generally warmed by 2–4oC in the past century

(Lachenbruch et al., 1982; Lachenbruch and

Marshall, 1986), although some locales show

little change or a slight cooling. Additional warming has occurred since that time (Clow and

Urban, 2002), although increased snow cover

may be responsible for a significant proportion

of the temperature increase near the surface

(Stieglitz et al., 2003).

Permafrost at many Arctic locations has

experienced temperature increases in recent

decades, including central and northern Alaska

(Lachenbruch and Marshall, 1986; Osterkamp
and Romanovsky, 1999), northwestern Canada

(Majorowicz and Skinner, 1997), and Siberia

(Pavlov, 1996). Temperature increases are not

uniform; cooling has occurred recently in permafrost in northern Quebec (Allard and Baolai,

1995). More recent observations indicate, however, that permafrost is warming rapidly in this

region (Allard et al., 2002). Serreze et al. (2000)

summarized the extent and geographic distribution of recent changes in permafrost temperature in the Arctic.

In Alaska, temperature measurements made

over the last two decades show that permafrost has warmed at all sites along a north–south

transect spanning the continuous and most of

the discontinuous permafrost zones, from Prudhoe Bay to Glennallen (Osterkamp and

Romanovsky, 1999). Modeling indicates that in

the continuous permafrost zone, mean annual

permafrost surface temperatures vary interannually within a range of more than 5oC. In

discontinuous permafrost, the observed warming is part of a trend that began in the late 1960s.

The total magnitude of the warming at the

permafrost surface since then is about 2oC.

Observational data indicate that the last “wave”

of recent warming began on the Arctic Coastal

Plain, in the Foothills, and at Gulkana in the mid1980s and in areas of discontinuous permafrost

about 1990 (typically 1989–1991). The magnitude of the observed warming at the permafrost surface is about 3–4oC at West Dock and

Deadhorse near the Arctic Ocean, about 2oC

over the rest of the Arctic Coastal Plain and

south into the Brooks Range, and typically 0.5–

1.5oC in discontinuous permafrost. At some sites

in discontinuous permafrost south of the Yukon

River, permafrost is now thawing from both the

top and the bottom. Thawing of ice-rich permafrost is presently creating thermokarst terrain

in the Alaskan interior and is having significant

effects on subarctic ecosystems and infrastructure (Jorgenson et al., 2001).

Permafrost also contains abundant proxy

information about climatic change. Cryostratigraphic techniques (Burn, 1997; French, 1998;

Murton 2001), combined with isotopic analysis,

can provide information about the increases in

active-layer thickness that occurred millenia ago

(Lauriol et al., 2002). Flora and fauna incorporated in permafrost can be dated radiometrically

to determine cooling episodes.

2.2.2 Translator: Permafrost

and Global-Change Impacts

Permafrost can translate climatic change to

other environmental components (Jorgenson et

al., 2001; Nelson et al., 2002). Thawing of icerich permafrost may induce settlement of the

ground surface, which often has severe consequences for human infrastructure and natural

ecosystems. Stratigraphic and paleogeographic

evidence indicates that permafrost will degrade

if recent climate warming continues into the

future (e.g., Kondratjeva et al., 1993). The

Arctic’s geological record contains extensive

evidence about regional, climate-induced deterioration of permafrost. Melting of glaciers in

Alaska and elsewhere will increase the rates

of coastal erosion in areas of ice-rich permafrost, already among the highest in the world.

Sediment input to the Arctic shelf derived from

coastal erosion may exceed that from river discharge (ACD, 2003).

Degradation of ice-rich permafrost has also

been documented under contemporary conditions in central Alaska and elsewhere (e.g.,

Francou et al., 1999; Osterkamp and

Romanovsky, 1999; Osterkamp et al., 2000; Jorgenson et al., 2001; Tutubalina and Ree, 2001;

Nelson et al., 2002; Beilman and Robinson,

2003). Little is known, however, about specific

processes associated with thawing of permafrost, either as a function of time or as a threedimensional process affecting the geometry of

permafrost distribution over a wide spectrum

of geographic scale. There is urgent need to

conduct theoretical, numerical, and field investigations to address such issues.

It is clear from the paleogeographic record

that climatic warming in the polar regions 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 could lead to extensive settlement of

the ground surface, with attendant damage to

infrastructure.

Chapter 2. Future Climate Change and Current Research Initiatives 15
16 Climate Change, Permafrost, and Impacts on Civil Infrastructure

Changes in Permafrost Distribution. Anisimov and Nelson (1996, 1997) investigated the

impact of projected climate changes on permafrost distribution in the Northern Hemisphere

using output from general circulation models

(GCMs). Predictive maps of the areal extent

of near-surface permafrost were created using

the “frost index” (ratio of freezing- to thawingdegree-day sums) to estimate the likelihood of

permafrost [see Nelson and Outcalt (1987) for

a derivation of the frost index]. The primary

conclusion of these experiments is that a significant reduction in the area of near-surface

permafrost could occur during the next century

(Fig. 10). Smith and Riseborough (2002)

recently presented an alternative, very promising computational method for addressing permafrost distribution under conditions of climate

change.

Until recently, however, GCMs did not

incorporate permafrost and permafrost-related

processes. During the last few years the GCM

community has developed a general understanding that, unless permafrost and permafrostrelated properties and processes are taken into

account, there is little reason to expect that

GCMs will produce physically reasonable results

(Slater et al., 1998 a,b). Including permafrost in

GCMs is a major challenge to both the GCM

and permafrost scientific communities. Without a solution to this problem, however, GCMs

cannot adequately represent arctic and subarctic

regions. Modeling is a powerful tool for both

climate and permafrost research. Although

there has been significant progress during the

last three decades, much remains to be done.

Changes in Active-Layer Thickness. The

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 dimensionless 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.
regions because most ecological, hydrological,

biogeochemical, and pedogenic activities take

place within it (Hinzman et al., 1991; Kane et

al., 1991). The thickness of the active layer is

influenced by many factors, including surface

temperature, thermal properties of the surface

cover and substrate, soil moisture, and the

duration and thickness of the snow cover

(Hinkel et al., 1997; Paetzold et al., 2000). Consequently, there is widespread variation in activelayer thickness across a broad spectrum of

spatial and temporal scales (e.g., Pavlov, 1998;

Nelson et al., 1999; Hinkel and Nelson, 2003).

The active layer can be thought of as a filter

that attenuates the temperature signal as it

travels from the ground surface into the underlying permafrost. The properties of this filter

change with time, behaving in a radically different manner in summer and winter because

of the changes in the phase of the water–ice

system (Hinkel and Outcalt, 1994). Over longer

time periods, the accumulation of peat at the

surface, cryoturbation, and ice enrichment at

depth can alter the filter properties. Thus, to

understand and interpret the signal recorded in

permafrost, monitoring programs must incorporate intensive active-layer observations. The

hypothesis and existing evidence that warming

will increase the thickness of the active layer,

resulting in thawing of ice-rich permafrost,

ground instability, and surface subsidence,

require further investigation under a variety of

contemporary environmental settings.

Several monitoring methods are used to measure seasonal and long-term changes in the

thickness of the active layer: physical probing

with a graduated steel rod at the end of the

thaw season (mid-August to mid-September),

temperature measurements, and stratigraphic

observations of ground ice occurrences (e.g.,

Burn, 1997; French, 1998; Murton, 2001). Other

recommended measurements include soil moisture and vertical displacement of the active layer

by thaw subsidence and frost heave. An

extended description of monitoring methods is

presented in the monograph by Brown et al.

(2000).

Measurements of thaw depth are often collected on plots or grids that vary between 10,

100, and 1000 m on a side, with nodes evenly

distributed 1, 10, or 100 m apart, respectively.

The gridded sampling design allows for analysis

of intra- and inter-site spatial variability (Nelson

et al., 1998, 1999; Gomersall and Hinkel, 2001;

Shiklomanov and Nelson, 2003). Summary

statistics are generated for each sample period,

and thaw depth on the grid is mapped using a

suitable interpolation algorithm.

Soil and near-surface permafrost temperatures are commonly determined with thermistor

sensors inserted in the ground, and subdiurnal

readings are made manually or recorded at regular time intervals by battery-operated dataloggers. Closely spaced thermistors in the upper

sections of shallow to intermediate-depth boreholes (25–125 m) provide continuous data to

interpolate active-layer thickness and to observe

interannual to decadal changes in permafrost

temperatures.

Changes in Soil Moisture and Ground Ice

Content. Soil moisture content has an important effect on soil thermal properties, soil heat

flow, and vegetation and is, therefore, a crucial

parameter. Although arctic hydrology has

received serious attention in science planning

documents, little attention has been devoted to

subsurface hydrologic and hydrogeologic processes in permafrost regions. The omission of

ground and soil water as a central focus is

unfortunate, because subsurface flow and subsurface storage are extremely important components in the arctic hydrological system and in

the arctic water cycle as a whole. Studies of

permafrost hydrogeology are rare in the U.S.

arctic sciences plans and programs. This is a

serious gap in the research agenda and monitoring programs, in both the high Arctic and the

Subarctic.

Several methods are employed to measure

soil moisture, including gravimetric sampling,

time-domain reflectometry (TDR), and portable soil dielectric measurements. Soil moisture

can vary over short distances, and near-surface

soil moisture fluctuates seasonally and in

response to transient rainfall events (e.g., Miller

et al., 1998; Hinkel and Nelson, 2003). Kane et

al. (1996) had some success using satellite-based

synthetic aperture radar to estimate soil moisChapter 2. Future Climate Change and Current Research Initiatives 17
18 Climate Change, Permafrost, and Impacts on Civil Infrastructure

ture in the Kuparuk basin. Ground-based radar

systems (e.g., Doolittle et al., 1990; Hinkel et

al., 2001) show considerable promise for directly

determining the long-term position of the active

layer over limited areas.

Frozen ground supersaturated with ice (i.e.,

containing excess ice) is particularly susceptible to thaw subsidence. Probing may not detect

this. Careful surveying is necessary to determine if thaw subsidence or frost heave has

occurred, but surveying is often not feasible.

Experiments involving high-precision (<1 cm)

differential GPS (global positioning systems) to

map and determine the scale of variability of

heave and subsidence are underway in northern Alaska (Little et al., 2003).

Changes in active-layer thickness, accompanied by melt of ground ice and thaw

settlement, can have profound impacts on local

environments (Burgess et al., 2000; Dyke and

Brooks, 2000). Where the distribution of ground

ice is not uniform, thawing can lead to differential subsidence, resulting in thermokarst terrain.

In the Sakha Republic (Yakutia) of Siberia, thaw

depressions coalesced during warm intervals of

the Holocene to form thaw basins (alases) tens

of meters deep and occupying areas of 25 km2

or more. Where human infrastructure has been

built on ice-rich terrain, damage to infrastructure can accompany thaw settlement (Fig. 8d

and f); recent geographic overviews indicate

that the hazard potential associated with icerich permafrost is high in many parts of the

Arctic (Nelson et al., 2001, 2002).

Modeling Strategies. Changes in the active

layer may be substantial in coming decades. To

predict such changes, modeling experiments are

required. Many formulations have been used to

calculate active-layer thicknesses and mean

annual permafrost surface temperatures using

simplified analytical solutions (Kudryavtsev et

al., 1974; Pavlov, 1980; Zarling, 1987; Balobaev,

1992; Aziz and Lunardini, 1992, 1993;

Romanovsky and Osterkamp, 1995, 1997; Smith

and Riseborough, 1996; Nelson et al., 1997).

For contemporary work involving locations for

which subsurface data are available, analytical

solutions are less important than in previous

decades. Numerical models are widely available for permafrost problems, and they can be

used with some confidence when adequate

information about climatic, boundary layer, and

subsurface parameters is available.

Analytical equations can also be helpful in

providing insights into the physics of the coupling between permafrost and the atmosphere.

However, these simple equations have limited

usefulness because they do not include the

effects of inhomogeneous active layers with

multiple layers, variable thermal properties,

unfrozen water dynamics, and non-conductive

heat flow.

Serious problems arise when complex

models are employed in a spatial context,

particularly when little is known about the spatial

variability of parameters important to geocryological investigation. In such cases,

stochastic modeling (Anisimov et al., 2002) or

the use of analytic procedures in a GIS environment (Nelson et al., 1997; Shiklomanov and

Nelson, 1999; Klene et al., 2002) may yield

results superior to complex, physically based

models.

Anisimov et al. (1997) used a series of GCMbased scenarios to examine changes in activelayer thickness in the Northern Hemisphere. The

results from these preliminary experiments

indicate that increases of 20–30% could occur

in many regions, with the largest relative

increases occurring in the northernmost areas

(Fig. 11).

Both empirical evidence (Moritz et al., 2002)

and climate models (e.g., Greco et al., 1994)

indicate that climate warming is not geographically homogeneous. With respect to degrading permafrost and its influence on human

settlement, a critical concern is the spatial

correspondence between areas of climate

warming (accompanied by active-layer thickening) (Fig. 11) and those of ice-rich permafrost (Fig. 3 and 5). These relations were

modeled by Nelson et al. (2001, 2002); the

results from those experiments are given in

Chapter 3. Harris et al. (2001b) have implemented a comprehensive, observation-based

approach to mapping geotechnical hazards

related to permafrost in the European mountains.
2.2.3 Facilitator: Permafrost

and Global Carbon Impacts

Permafrost can facilitate further climate

change through the release of greenhouse gases

(Rivkin, 1998; Robinson and Moore, 1999; Robinson et al., 2003). Because considerable quantities of carbon are sequestered in the upper

layers of permafrost, a widespread increase in

the thickness of the thawed layer could lead to

the release of large quantities of CO2 and CH4

to the atmosphere (Michaelson et al., 1996;

Anisimov et al., 1997; Goulden et al., 1998;

Bockheim et al., 1999). This in turn would create

a positive feedback mechanism that can amplify

regional and global warming.

Concerns have been raised about the impact

of high-latitude warming on the global carbon

cycle. According to Semiletov (1999) the greatest concentration and largest seasonal variations

of carbon dioxide and methane concentrations

occur between 60o and 70oN. Greenhouse gases

released from thawing permafrost into the atmosphere could create a strong positive feedback in

the climate system; this topic is currently under

intensive investigation. Key questions include:

• What are the major mechanisms regulating

the distribution and associated rates of carbon transfer, transformation, and burial in

the arctic land–shelf system?

• How do biogeochemical processes on the

margins of the Arctic Ocean influence the

chemistry and biology of surface waters and

associated fluxes of CO2 at the air–water

(ice) interface?

Answers to such questions require much more

work on the state of offshore and onshore

permafrost in the atmosphere–land–shelf

system in the Arctic.

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%.

Chapter 2. Future Climate Change and Current Research Initiatives 19
20 Climate Change, Permafrost, and Impacts on Civil Infrastructure

Plants remove carbon dioxide from the

atmosphere during photosynthesis. Carbon

dioxide is returned through plant respiration and

decomposition of plant detritus. Studies on

Alaska’s North Slope indicate a delicate balance between these two competing processes.

In some years, more CO2 is released into the

atmosphere, while in others more CO2 is fixed

by plants (Marion and Oechel, 1993; Oechel et

al., 1993). In years when biomass production

exceeds respiration, the atmosphere is a net

source of carbon, which resides in plant biomass.

Regional changes in climate can alter the vegetation communities and thus alter this balance

in a direction not fully understood. Studies from

Canada and Eurasia have demonstrated that

many arctic sites are currently losing CO2 to

the atmosphere (Zimov et al., 1993, 1996).

Higher temperatures and a reduction in soil moisture appear to be likely causes (Oechel et al.,

1995, 1998).

Plants lose biomass as part of their natural

growth cycle. They shed leaves and twigs, and

they disperse seeds. In wet tundra, much of

this surface detritus decays only partially, yielding a surface soil layer rich in organics. The

organics can be transported deeper into the soil

via several processes. In summer, water percolating through the active layer can transport

organics to depth. In winter, soils are susceptible to a mechanical churning process known as

cryoturbation. Over long time periods, surface

materials are transported down into the soil and

can become incorporated into the upper permafrost. This storage (sequestration) of carbon in

the upper permafrost has been documented in

several studies (Michaelson et al., 1996; Bockheim et al., 1999). Terrestrial arctic ecosystems

may have been a net carbon sink during the

Holocene, and perhaps 300 gigatons are sequestered (Miller et al., 1983).

Thickening of the seasonally thawed layer

effectively means downward movement of the

permafrost table. If organic material is present

in the newly thawed layer, it again becomes

subject to decomposition by soil microbes, ultimately releasing CO2 and CH4 to the atmosphere. This can act as a positive feedback

mechanism by increasing the concentration of

radiatively active gases in the high-latitude

regions. By one estimate, carbon fluxes have

the potential for a positive feedback on global

changes amounting to about 0.7 Gt per year of

carbon to the atmosphere, about 12% of the

total emission from fossil fuel use (Oechel and

Vourlitis, 1994).

High-latitude wetlands currently account for

about 5–10% of the global methane flux (Reeburgh and Whalen, 1992), and, because methane flux is related closely to the thermal regime

in the active layer (Goulden et al., 1998; Nakano

et al., 2000), this component is likely to increase

if the development of widespread thermokarst

terrain is triggered by permafrost degradation.

Thermokarst lakes emit methane during winter;

methane is generated from carbon-rich terrestrial sediments sequestered during the Pleistocene epoch (Zimov et al., 1997).

Embedded within sediments on the ocean

margins is a crystalline form of methane known

as gas hydrates (e.g., Yakushev and Chuvilin,

2000). Although currently in quasi-equilibrium

with temperature and pressure conditions, large

volumes of gas hydrates are susceptible to

disruption by warming ocean water. This could

result in the release of these hydrocarbons,

allowing them to escape to the surface and enter

the atmosphere. Since methane has a radiative

activity index of about 27 (molecule for molecule, it is 27 times more effective at absorbing

thermal radiation than CO2), this could provide

a strong positive feedback.

2.3 Monitoring: Organized

International Collection,

Reporting, and Archiving Efforts

Worldwide permafrost monitoring can

provide evidence of climate-induced changes.

Standardized in-situ measurements are also

essential to calibrate and verify regional and

GCM models. The Global Terrestrial Network

for Permafrost (GTN-P) is the primary international program concerned with monitoring

permafrost parameters. GTN-P was developed

in the 1990s with the long-term goal of obtaining

a comprehensive view of the spatial structure,

trends, and variability of changes in permafrost
temperature (Brown et al., 2000; Burgess et

al., 2000). The program’s two components are:

(a) long-term monitoring of the thermal state of

permafrost in an extensive borehole network;

and (b) monitoring of active-layer thickness and

processes at representative locations. The

active-layer program, titled Circumpolar Active

Layer Monitoring (CALM), is described in a

monograph by Brown et al. (2000).

The ideal distribution of sites for a global or

hemispheric monitoring network should include

locations representative of major ecological,

climatic, and physiographic regions. Recently,

efforts have been made to re-establish a deep

borehole temperature monitoring program under

the auspices of GTN-P to monitor, detect, and

assess long-term changes in the active layer

and the thermal state of permafrost, particularly

on a regional basis (Burgess et al., 2000;

Romanovsky et al., 2002). The borehole network has 287 candidate sites, half of which

obtain data on a periodic basis. Borehole metadata are available on the Geological Survey of

Canada’s permafrost web site.

The International Permafrost Association

(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,

many data sets related to the thickness of the

active layer were collected as part of larger

geomorphological, ecological, or engineering

investigations, using different sampling designs

and collection methodologies. Moreover, the

typical study was short term and did not deposit

data records in archives accessible for general

use (Barry, 1988; Clark and Barry, 1998). The

combined effect of these circumstances made

it difficult to investigate long-term changes in

seasonal thaw depth or possible interregional

synchronicity.

The CALM program was formally established in the mid-1990s as a long-term observational program designed to assess changes in

the active layer and provide ground truth for

regional and global models. It represents the

first attempt to collect and analyze a large-scale,

standardized geocryological data set obtained

using methods established under an international

protocol. Funded by the Arctic System Science

(ARCSS) program of the U.S. National Science

Foundation, the network currently incorporates

approximately 125 active sites involving participants from twelve countries in the Northern

Hemisphere and three countries involved in

Antarctic research. The majority of the network

sites are in arctic tundra regions, with the

remainder in warmer forested subarctic and

alpine tundra of the mid-latitudes. Metadata and

ancillary information are available for each site,

including climate, site photographs, and descriptions of terrain, soil type, and vegetation. CALM

data are transferred periodically to a permanent archive at the National Snow and Ice Data

Center (NSIDC) in Boulder, Colorado.

GTN-P and the CALM program contribute

to the Global Terrestrial Observing System

(GTOS), the Global Climate Observing System

(GCOS), and the associated Terrestrial Ecosystem Monitoring Sites (TEMS) network. The

networks are co-sponsored by the World

Meteorological Organization (WMO), the

Intergovernmental Oceanographic Commission

(IOC of UNESCO), the United Nations Environment Programme (UNEP), the International

Council of Scientific Unions (ICSU), and the

Food and Agriculture Organization (FAO). A

detailed joint plan for GCOS and GTOS was

developed by the Terrestrial Observational

Panel for Climate (TOPC) for climate-related

observations (GCOS, 1997). Program goals

include early detection of changes related to climate, documentation of natural climate variability and extreme events, modeling and prediction

of these changes, and assessment of impacts.

The affiliation of GTN-P and the CALM

program within the GCOS/GTOS networks

Chapter 2. Future Climate Change and Current Research Initiatives 21

Web Sites

GTN-P http://www.gtnp.org

CALM http://www.geography.uc.edu/~kenhinke/CALM/

CEON http://ceoninfo.org/

FGDC http://nsidc.org/fgdc/

PACE http://www.earth.cardiff.ac.uk/research/geoenvironment/

pace/31.EU_PACE_Project.htm

IPA http://www.soton.ac.uk/ipa
22 Climate Change, Permafrost, and Impacts on Civil Infrastructure

The GTN-P network seeks to implement an integrated,

multi-level strategy for global observations of permafrost

thermal state, active layer thickness, and seasonally

frozen ground, including snow cover, soil moisture, and

temperature by integrating (a) traditional approaches and

new technologies, (b) in-situ and remote observations,

and (c) process understanding and global coverage. The

provisional tiered system corresponds to the Global

Hierarchical Observing Strategy (GHOST) developed for

key variables of GTOS and includes:

Tier 1: Major assemblages of experimental sites

[Kuparuk River basin, Alaska; Mackenzie River

basin, Canada; Lower Kolyma River, Russia;

Permafrost and Climate in Europe (PACE)

transect from southern Europe to Svalbard].

Tier 2: Process-oriented research sites [Long-term

Ecological Research (LTER) sites and Barrow

(Alaska); Zackenberg (Greenland); Abisko

(Sweden); and Murtel/Corvatsch (Switzerland)].

Tier 3: Range of environmental variations including

ground temperatures and plots [CALM hectare

to 1-km2 grids; boreholes across landscapes

gradients (southern Norway, Swiss Alps, Lake

Hovsgol GEF in Mongolia)].

Tier 4: Spatially representative grids associated with

gas flux, active layer, and borehole measurements

[northern Alaska and Lower Kolyma, Russia,

including MODIS and Fluxnet sites (such as

Barrow, Alaska)].

Tier 5: Application of remotely sensed data covering

entire regions [low state of development in geocryology due to difficulties in remotely sensing

subsurface temperatures, ground ice, and frost

penetration].

Tiers 1–4 mainly represent traditional methodologies,

which remain fundamentally important for a deeper

understanding of processes and long-term trends. Tier 5

constitutes challenges for scaling experiments and

regional model validation, although progress has been

made in active-layer mapping (Peddle and Franklin, 1993;

Leverington and Duguay, 1996; McMichael et al., 1997).

Activation of additional existing boreholes and establishment of new boreholes and active layer sites are required

for representative coverage in the Europe/Nordic region,

Russia and Central Asia (Russia, Mongolia, Kazakhstan,

China), in the southern hemisphere (South America, Antarctica), and in the North American mountain ranges and

lowlands. Additional cooperative activities through the

NSIDC Frozen Ground Data Center are required to

obtain data from continental regions where existing seasonal soil frost observations are collected.

Figure 12, modified from Brown et al. (2000), represents an established application of a hierarchical, GHOSTlike strategy in permafrost science. The active-layer thickness in the 26,278-km2 area (Tier 1), centered on the

Kuparuk River basin of north-central Alaska, is mapped

using data from the array of experimental and observation sites located within it. A wide range of intensive monitoring programs and manipulative experiments are

conducted at the Toolik LTER site, which represents Tier

2. Soil and vegetation characteristics are collected at 1-

km2 Tier 3 sampling grids (squares) and are used for

field experiments (e.g., frost heave and thaw settlement)

and model verification. Small (1-ha) Tier 4 sites, represented by triangles, are distributed throughout the region

and are used to collect air temperature, surface temperThe GHOST Hierarchical Sampling Strategy

necessitates conformity with global

observational protocols whenever and wherever

possible. The Global Hierarchical Observing

Strategy (GHOST) represents a strategic effort

to obtain samples of environmental variables

that can be integrated systematically over time

and space to provide comprehensive estimates

of the rates and magnitude of global-change

impacts (WMO, 1997). The basic objective of

GHOST site selection is to obtain valid regional

and global coverage while taking maximum advantage of existing facilities and sites. The

GHOST system incorporates a five-tier hierarchical system for surface observations; a more
Chapter 2. Future Climate Change and Current Research Initiatives 23

ature, and thaw-depth data. Vegetation and digital

elevation model (DEM) maps of the area, derived from

satellite data, represent Tier 5 and are used to interpolate

data over the entire map area. Details are given in Nelson

et al. (1997) and Shiklomanov and Nelson (2002). The

GHOST approach lends itself to a wide variety of

analytical and modeling approaches. Alternative methodologies for producing active layer maps of this region

have been explored by Hinzman et al. (1998), Shiklomanov and Nelson (1999), Anisimov et al. (2002), and

Klene et al. (2001). Information about the Tier 3

(ARCSS/CALM) grids is contained in Nelson et al. (1998)

and Hinkel and Nelson (2003). The Tier 4 (Flux Study)

sites are discussed by Klene et al. (2001).

complete generic description can be found in

Version 2.0 of the GCOS/GTOS Plan for Terrestrial Climate-related Observations (GCOS,

1997; WMO, 1997). Permafrost observation

sites and networks will play an important role in

the developing Circumarctic Environmental Observatories Network (CEON).

2.4 Organizational Issues

Standardized collection of basic environmental parameters is essential to all large-scale

scientific and engineering endeavors. With

respect to permafrost, there is a clear need to

establish a systematic data-reduction protocol

Figure 12. Example of a GHOST-like hierarchical sampling strategy and

time-series analysis, Kuparuk River basin, Alaska (Brown et al., 2000).
24 Climate Change, Permafrost, and Impacts on Civil Infrastructure

in accordance with identified and established

user needs. For example, hourly air temperature data collected by an individual field

researcher may not be necessary for climate

modelers and engineers. Instead, such data

could be processed to produce average daily

air temperatures or accumulated degree-days

of frost, thaw, heating, or cooling. Implicit in

such an approach is the recognition that basic

aspects of data collection would be standardized (e.g., all air temperature measurements

would be made at the same height above the

ground surface using a standard radiation shield)

and that metadata files would also be available.

These data, if properly collected, provide the

foundation upon which all efforts ultimately

depend, and they are used to refine and validate climate modeling efforts.

A specific measurement protocol should be

developed for monitoring permafrost. This protocol should be established by the scientific and

engineering community for obtaining the

appropriate measurements at the necessary

temporal frequency and spatial resolution. The

protocol should cover the scale of instrumentation ranging from site to satellite. Inherent in

the protocol is the requisite accuracy and precision of thermistors, the optimal depth of soil

temperature measurements, and site descriptions. These efforts should be coordinated and

integrated with those of the GTN-P to ensure

the collection of data useful for global climate

observation (Burgess et al., 2000; GTN-P web

site). Similarly, methods of monitoring active

layer thickness and thaw subsidence should be

integrated with those of ongoing and developing international projects (e.g., CALM, PACE,

IPY) following discussion and modification of

the protocols currently in place. In all cases, an

effort should be made to assess the spatial variability of thaw depth and soil temperature and

to collect ancillary data. A comprehensive list

of recommendations regarding permafrostrelated activities and their coordination was

issued recently (IPA Council, 2003).

The 24-member International Permafrost

Association (IPA) and several of its working

groups and data committees coordinate GTNP activities, including input to GTOS/TEMS.

The Geological Survey of Canada (Ottawa)

maintains the GTN-P web site and borehole

metadata files and coordinates thermal data

management and dissemination The NSIDC

acquires, stores, and processes data. Data

collected by funded projects in the U.S. should

be archived in the Frozen Ground Data Center

(FGDC) within an appropriate time period.

FGDC is a subunit of the U.S. National Snow

and Ice Data Center (NSIDC) in Boulder,

Colorado, which is an affiliate of the World

Data Center for Glaciology (WDC). Details

of site characteristics and measurements

should be presented in standardized metadata

files.

A strategy developed by the IPA facilitates

data and information management to meet the

needs of cold regions science and engineering.

One focus of this strategy is the Global Geocryological Data (GGD) system, which provides

an international link for scientific investigators

and data centers. In collaboration with the

International Arctic Research Center (IARC),

WDC and NSIDC serve as a central node for

GGD. Every five years NSIDC prepares a CDROM containing information and data acquired

in the previous five-year interval. Known as the

Circumpolar Active-Layer Permafrost System

(CAPS), this product is a comprehensive compilation of data related to permafrost and frozen

ground from a global perspective. Detailed

information can be found on the FGDC web

site.

Data sets representing spatially intensive

measurements, such as satellite imagery or thaw

depths interpolated over large regions, should

be prepared in a format conducive to generation of descriptive statistics and standardized

mapping. Digital mapping at regional, continental, and circumpolar scales has been facilitated

greatly by the development of the Equal-Area

Scalable Earth Grid (EASE-Grid) at NSIDC

(Armstrong et al., 1997). Use of this flexible

system of projections is recommended at these

scales.
3.1 Introduction

Evidence presented in the preceding chapters documents widespread warming of permafrost, which in some cases is showing very clear

evidence of thawing. Warming and thawing of

permafrost will have significant effects on

infrastructure (Instanes, 2003). Local sources

of anthropogenic heat and surface modifications

associated with urban land uses may exacerbate problems related to thaw and settlement

(Hinkel et al., 2003b; Klene et al., 2003). After

presenting a general overview of the possible

effects of climate warming on permafrost in

the Northern Hemisphere, this chapter discusses

the existing infrastructure in Alaska with special reference to its relation with permafrost.

3.2 Northern Hemisphere Hazards

Nelson et al. (2001, 2002) used output from

three transient-mode general circulation models

(GCMs), in conjunction with a digital version of

the International Permafrost Association’s

Circum-Arctic Map of Permafrost and

Ground Ice Conditions (Brown et al., 1997,

1998; Brown and Haggerty, 1998), to map the

hazard potential associated with thawing permafrost under conditions of global warming. The

maps were created using a simple, dimensionless thaw-settlement index, computed using the

relative increase in active layer thickness and

the volumetric proportion of near-surface soil

occupied by ground ice. Computational details

are provided in Nelson et al. (2002). The

resulting maps depict areas of low, moderate,

and high hazard potential. In Figure 13 the

location of existing infrastructure has been

superimposed on the hazard map, providing a

general assessment of the susceptibility of

engineered works to thaw-induced damage

under the UKTR climate-change scenario. Figure 13a indicates the risk to infrastructure in

northern Canada, Alaska, and Russia. Russia

has more population centers and infrastructure

in the higher risk areas, but Alaska and Canada

also have population centers, pipelines, and roads

in areas of moderate and high hazard potential.

Major settlements are located in areas of moderate or high hazard potential in central and

northern Alaska (e.g., Nome and Barrow),

northwestern Canada (Inuvik), western Siberia

(Vorkuta), and the Sakha Republic in Siberia

(Yukutsk). The potential for severe thawinduced disruptions to engineered works has

been reported from each of these areas, and

problems are likely to intensify under conditions

of global warming.

Figure 13b shows the risk to transportation

facilities. The network of seismic trails in northern Alaska, the Dalton Highway between the

Yukon River and Prudhoe Bay in Alaska, the

Dempster Highway between Dawson and

Inuvik in western Canada, and the extensive

road and trail system in central Siberia all

traverse areas of high hazard potential. Numerous airfields occupy ice-rich terrain in Siberia,

and the Trans-Siberian, Baikal-Amur Mainline,

Hudson Bay, and Alaska Railroads span regions

of lesser hazard potential, although they extend

into areas in which localized problems have been

reported. A dense network of secondary roads

and trails occupies areas of moderate risk in

Mongolia, and northeastern China has an

Chapter 3

IMPACTS ON INFRASTRUCTURE IN ALASKA

AND THE CIRCUMPOLAR NORTH
26 Climate Change, Permafrost, and Impacts on Civil Infrastructure

Figure 13. Areas at risk for infrastructure damage as a result of thawing of permafrost.

a. Risk to infrastructure.

The red dots indicate

population centers; the

pink shading indicates

areas of human settlement.
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.
extensive railway system developed in areas

underlain by permafrost.

The risk to major electrical transmission lines

and pipelines is shown in Figure 13c. Most electrical facilities, including the extensive networks

in northern Scandinavia and south-central

Siberia, are located in areas of moderate risk.

The Bilibino nuclear station and its grid, extending from Cherskiy on the Kolyma River to Pevek

on the East Siberian Sea, occupy an area in

which increased thaw depth and abundant icerich permafrost combine to produce high hazard potential. The Trans-Alaska Pipeline System spans two areas of moderate hazard

potential. The network of pipelines associated

with the West Siberia oil and gas fields is of

particular concern because it is located in the

ice-rich West Siberian Plain and is vulnerable

to freeze–thaw processes (Seligman, 2000).

Figure 13 provides a generalized delineation

of regions in the Northern Hemisphere to which

high priority should be assigned for monitoring

permafrost conditions. At the circum-arctic

scale, maps such as these are useful for developing strategies to mitigate detrimental impacts

of warming and adaptation of the economy and

social life to the changing environment of northern lands. Maps at such scales cannot, of course,

resolve the local factors involved in the development of thermokarst. Rather, they point to

geographic areas where hazard scientists, policy

analysts, and engineers should focus attention

and prepare more detailed maps at local and

regional scales.

3.3 Geocryological Hazards in Alaska

Figure 14 shows the population centers and

major roads in areas of Alaska that are presently affected by permafrost. Although a

majority of the population resides in permafrostfree areas of the state, sizeable towns and settlements are located in areas that are susceptible to permafrost degradation; nearly 100,000

Alaskans live in areas vulnerable to permafrost

degradation (Fig. 14). Moreover, many of the

state’s highways traverse areas underlain by

permafrost. The remainder of this chapter

updates earlier reviews by Muller (1947),

Ferrians et al. (1969), and Péwé (1954, 1983b)

by considering how warming permafrost may

affect transportation, the Trans-Alaska Pipeline, and community infrastructure.

3.3.1 Transportation Network

The State of Alaska agency primarily responsible for transportation infrastructure is the

Department of Transportation and Public

Facilities (ADOT&PF). The ADOT&PF discusses the history, present status, and plans for

road, rail, air, and marine transportation infrastructure in its Vision 2020 Update, Statewide

Transportation Plan (ADOT&PF, 2002). With

respect to the present status of roads, this report

notes that “...Alaska is twice the size of Texas,

but its population and road mileage compare

more closely with Vermont....” The state has

approximately 12,700 miles of roads, about 30%

(less than 4,000 miles) of which are paved.

Gravel and dirt roads are by far the most common design. The majority of the state’s roads

are in the south-central region, where permafrost is discontinuous and sparse. Roads in the

interior, particularly north of Fairbanks (i.e., the

gravel Dalton Highway), traverse areas underlain by ice-rich permafrost and may require

substantial rehabilitation or relocation if thaw

occurs.

The Alaska Railroad extends from Seward

to Fairbanks, crosses permafrost terrain, and

has been affected by differential frost heave

and thaw settlement in places (Ferrians et al.,

1969). The railroad does not extend northward

into the zone of continuous permafrost. Thaw

of ice-rich permafrost will increase railway

maintenance costs but should not require major

relocations of the existing track. Plans to extend

the track to Canada across the interior will

involve routing through permafrost areas.

Selecting a route that avoids ice-rich permafrost foundations will increase the track mileage and construction cost.

Alaska has 84 commercial airports and more

than 3,000 airstrips. The state has 285 publicly

owned airports, 261 of which are owned by the

state government, including 67 paved airstrips,

177 gravel airstrips, and 41 seaplane ports. Many

of the state’s rural communities depend exclu28 Climate Change, Permafrost, and Impacts on Civil Infrastructure
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. Geological Survey, International Permafrost Association, and Alaska Department of Natural Resources GIS

database.

sively on a local airstrip for transporting passengers and freight, including heating fuel. A

significant number of airstrips in communities

of southwest, northwest, and interior Alaska are

built on permafrost and will require major repairs

or complete relocation if their foundations thaw.

The vulnerability of Alaska’s network of

transportation infrastructure to thawing of

permafrost can and should be assessed systematically. Roads, railways, and airstrips placed

on ice-rich continuous permafrost will generally

require relocation to well-drained natural foundations or replacement with substantially

different construction methods. Roads through
30 Climate Change, Permafrost, and Impacts on Civil Infrastructure

discontinuous permafrost will require this reinvestment for reaches built on ice-rich permafrost. Roads and airstrips built on permafrost

with a lower volume of ice will require rehabilitation, but perhaps not relocation, as the foundation thaws.

Site-specific information is most desirable for

this purpose, but the information contained on

permafrost maps can be applied to compute an

expected value of road miles over each category of permafrost. Figure 14 shows the major

road routes of the state and the locations of

communities, shaded to indicate whether they

are situated in areas of continuous, discontinuous, or sporadic permafrost. Thawing of various

types of permafrost is predictable by analyses

based on knowledge of soil conditions and air

temperature warming projections. A timeline for

serious permafrost-related problems could be

derived from projections of general circulation

models in a manner similar to that of Nelson et

al. (2001). Expected values of relocation and

rehabilitation can be developed, given estimates

of per-mile design and construction costs. A

master plan of climate-change-induced major

relocation and rehabilitation projects can be

formed with this information. The information

can also be applied efficiently to locate stations

to monitor permafrost warming where it matters most. This effort could best be accomplished comprehensively through the combined

resources and efforts of the state and federal

governments.

3.3.2 Community Infrastructure

Community infrastructure includes facilities

in urban and rural communities that are not

associated with the transportation network or

the Trans-Alaska Pipeline. Examples of community infrastructure include private and public

buildings, landfills, sewer and water facilities,

solid waste facilities, electrical generating

facilities, towers, antennas, and fuel storage

tanks. Figure 14 shows the locations of settlements in Alaska with regard to permafrost

susceptibility. Although the major population

center in the Anchorage area is largely free of

permafrost, over 160 communities lie in areas

of continuous or discontinuous permafrost.

Alaska has four large military bases, two of

which must contend with discontinuous permafrost. Alaska also has 600 former defense sites.

Russia has an even greater problem, with a

significant number of population centers, industrial complexes (including one nuclear power

plant), and military bases in permafrost areas

(Ershov et al., 2003). The continuous permafrost in the far north forces essentially all facilities to be constructed on permafrost. Farther

south, in areas of discontinuous permafrost, land

ownership and needs often force facilities to be

developed on permafrost.

The permafrost underlying most of the state

is the key reason why Alaskan infrastructure

will be affected by a warming climate far

greater than any other region of the U.S. Thawing permafrost poses several types of risks to

community infrastructure. Most are associated

with the thawing of ice-rich permafrost, which,

when thawed, loses strength and volume. The

most basic risk is caused by the loss of

mechanical strength and eventually thaw

settlement or subsidence. Thaw settlement

causes the failure of foundations and pilings,

affecting all types of community infrastructure.

Bond strengths between permafrost and piles

are greatly reduced by rising temperatures.

Increases in the thickness of the active layer

can cause frost heaving of pilings and structures. Warming will also accelerate the erosion

of shorelines and riverbanks, threatening the

infrastructure located on eroding shorelines.

Thawing of permafrost or increasing the thickness of the active layer can also mobilize

pollutants and contaminants that are presently

confined (Snape et al., 2003).

Thawing permafrost and changes in the

active layer across Alaska will bring potentially

adverse impacts to building foundations and

support structures. The past is replete with

examples of public and private facilities that have

failed due to warming and subsidence of the

underlying permafrost because of improper

siting, design, and construction methods. Thaw

subsidence has resulted in numerous cases of

expensive fixes or abandoned facilities. During

new construction, if ice-rich permafrost cannot

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

include digging out the permafrost if it is relatively shallow and thin, raising the structure on

piles, or otherwise assuring that the substrate

remains frozen through active or passive refrigeration. Mitigating existing problems is difficult

and expensive, requiring reconstruction of the

building support system, as well as repairing the

damage to the structure. Warming creates

further problems, however. If mean annual air

temperatures rise above the freezing point, it

will be impossible to maintain permafrost over

the long term without expensive artificial refrigeration. The largest problem will be for those

areas where the upper permafrost layers are

already near the freezing point, primarily in

regions of discontinuous permafrost. Larger

facilities, such as schools and tank farms, will

be affected first. Continued warming will cause

problems even for those facilities that were properly designed to maintain the underlying permafrost in its frozen state. New approaches for

maintaining existing structures and building new

structures on permafrost must be developed to

account for increases in soil temperatures.

Thaw subsidence is also a problem for utility

distribution networks and communications

facilities. These facilities are usually based on

foundations or pilings. Frost heaving of piles can

result from increased active-layer thickness.

One of the major effects of thawing ice-rich

permafrost is the development of thermokarst

terrain. Uneven surfaces created by differential thaw settlement will cause problems with

above-ground power lines, water, sewer, and

fuel piped systems. Piped systems are especially susceptible to settlement and subsequent

leakage (Williams, 1986).

In many arctic communities, modern sewer

and water facilities are non-existent. Many villages still use “honeybucket” (storage and haul)

systems in which human waste is emptied into

a pit or lagoon in or near the town. Many of the

towns with more modern facilities also have

lagoons where waste is dumped or piped.

Sewage disposal systems that are designed for

subsurface discharge may benefit from less

extensive permafrost, increased water table

depth, and increased groundwater flow rates.

For systems that discharge into streams or

rivers, increased stream flow and reduced ice

cover will help aerate and dilute the effluent.

Landfills containing solid waste pose problems

in that contaminants confined by the frozen

ground may be released and transported as the

permafrost thaws. The problem is amplified

because there is often far more than solid waste

in landfills and at many other locations near

villages. Past practice throughout the north has

ignored proper disposal of contaminants because

of the associated expense and the perception

that permafrost acts as an impermeable barrier.

Some villages or facilities located on riverbanks or exposed coastlines are facing major

problems with erosion (Walker and Arnborg,

1966; USACE, 1999; Walker, 2001). Warming

has contributed to longer ice-free seasons in

arctic areas. Riverbank erosion has destroyed

homes and public infrastructure in some villages

(USACE, 1999). Increased storminess and

higher waves are eroding arctic coasts at greater

rates than in the past (Brown et al., 2003). The

combination of increased wave action and

warming permafrost especially threatens lowlying coastal villages (Walker, 2001). Several

villages in Alaska have lost buildings to the sea

(Callaway et al., 1999). In some cases, entire

villages may have to be relocated. Abandoning

and rebuilding communities will have the

secondary effect of generating large amounts

of solid waste.

The costs associated with rehabilitating or

abandoning community infrastructure damaged

by thawing permafrost will be high. Even buildings that have been designed for ice-rich permafrost will not survive unscathed if the temperature rises to the point that systems designed to

maintain permafrost in its frozen state no longer

function adequately. Electrical distribution

systems and pipe and utilidor systems will be

subject to failure from subsidence or frost

heaving. Contaminants could be released from

landfills and other contaminant storage sites once

thought to be safe. Huge costs will be associated

with villages that must be relocated. In one case

study by the Corps of Engineers in 1998, the

costs of moving the village of Kivalina, Alaska,

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

can be expected to have problems with warming permafrost and may require additional relocations.

The military has extensive facilities in Alaska.

Two of its largest bases and a major training

facility are located in areas of discontinuous

permafrost, and they must constantly cope with

problems caused by thawing permafrost (Cole,

2002). There are also 600 formerly used

defense sites in Alaska. Alaska is also used

extensively for training, requiring access by military vehicles and live firing of munitions. The

development of thermokarst terrain would make

some training lands unusable. Additional

precautions will be necessary for contaminants

generated by the military, some of which are

associated with the use of live munitions. Permafrost must be considered in Department of

Defense plans for new facilities, including the

National Missile Defense sites being contemplated for Alaska.

3.3.3 The Trans-Alaska Pipeline

The Trans-Alaska Pipeline System (TAPS),

the only large-diameter hot-oil pipeline to traverse

environmentally sensitive permafrost terrain

(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 permafrost soil and temperature conditions (Kreig and

Reger, 1983). To avoid permafrost degradation,

soil liquefaction, and subsidence, pipeline along

434 of the 800 miles of the TAPS was elevated

on vertical support members (VSMs) (Fig. 16).

The VSMs represented a new approach to

engineering when they were designed in the

early 1970s. Design standards were based on

the permafrost and climate conditions of the

period 1950–1970. The objectives of the design

were to eliminate thawing of permafrost soils

and maintain soil stability (Williams, 1986, Chapter 4).

About 61,000 of the 78,000 VSMs are

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 Environmental 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

Company nor the JPO regard permafrost degradation as a problem. This interpretation is

based, however, on the present permafrost and

climate conditions and does not consider the

Arctic Climate Impact Assessment predictions

for the next 30 years. It is important to note

that the 20-year period used to determine design

standards was one of the coldest periods in

recent Alaskan history.

The TAPS right-of-way leases from the

federal and state governments terminate in

2004, and the owner companies plan to ask for

a 30-year renewal. The original VSM design

represented a coordinated effort by the Alyeska

owners with strong oversight by the TAPS

Federal Inspectors Office. That office relied

Figure 16. Vertical support members (VSMs) along the Trans-Alaska Pipeline System.
34 Climate Change, Permafrost, and Impacts on Civil Infrastructure

upon the expertise of the U.S. Army Cold

Regions Research and Engineering Laboratory

(CRREL) and the USGS for identification of

soil and permafrost problems; continuing

operations should incorporate similar cooperative efforts.

In addition to the TAPS segments elevated

on VSMs, soil stability in non-permafrost areas

where the pipeline is buried may be affected.

While there was no permafrost located immediately adjacent to the buried pipeline, changes

in freeze–thaw depth, water table location, and

soil bearing capacity may cause degradation in

downslope areas, river crossings, and other

areas.

The TAPS cannot be discussed without mentioning the large infrastructure on the North

Slope, which provides the oil to the pipeline.

Literally tens of billions of dollars of construction is responsible for drilling pads, production

installations, injection plants, pump stations, and

hundreds of miles of feeder pipelines. Although

these facilities are located on the colder permafrost north of the Brooks Range, which may

not be as susceptible to thawing as is the warmer

permafrost, their impacts have been substantial

(Walker et al., 1987; Committee on Cumulative

Environmental Effects, 2003, Chapter 6) and

close monitoring is critical.

3.4 Summary

A significant proportion of Alaska’s population and infrastructure is located in areas of

permafrost, much of which may become

unstable under conditions of global warming.

Although much of this infrastructure was

designed for permafrost, substantial retrofitting

to accommodate warming conditions may be

necessary. In many instances designs are clearly

inadequate, and infrastructure could be severely

damaged by differential thaw settlement.

The problems presented by climate warming in Alaska, although substantial, are not

insurmountable. To achieve maximum effectiveness in an era of declining oil revenues and

limited financial resources for both industry and

government at all levels, a prevenient, wellinformed, and coordinated response to the

effects of global warming on permafrost is

essential. The last chapter of this report provides

a general prescription for the roles governmental agencies can and should play in permafrost

research.
Chapter 4

FINDINGS AND AGENCY RECOMMENDATIONS

Members of the U.S. Arctic Research Commission Permafrost Task Force met in Salt Lake

City, Anchorage, San Francisco, and Seattle

between November 2001 and December 2003.

Discussions were also held with scientists, private industry, the U.S. Permafrost Association,

senior managers of federal agencies, and State

of Alaska departmental personnel. An integration of these meetings and discussions with the

background provided by Chapters 1 through 3

of this report resulted in the following findings

and recommendations. The entire report with

recommendations has been reviewed by the

Commissioners and five independent, outside

reviewers.

4.1 U.S. Federal Permafrost

Research Programs

4.1.1 Permafrost: Equal Attention

Despite publication of several reports specifying needs and strategies (Committee on

Permafrost, 1974, 1975, 1976, 1983; Brown and

Hemming, 1980), permafrost research, both

basic and applied, has received less attention

within U.S. government research programs than

it warrants. This situation may in part result

from a perception that permafrost is very slow

to respond to climate change. On the contrary,

permafrost has significant roles in climate

change: as a record keeper of past temperatures, as a translator of climate change through

the effects of its degradation on ecosystems and

human infrastructure, and as a facilitator through

its potential for release of sequestered carbon.

The importance of permafrost in the global system, combined with our incomplete understanding of the role and behavior of frozen ground and

associated processes, dictates that permafrost

research should have equal weight with other

components of the cryosphere in climate-change

research. The Task Force believes it is critical

that programs such as SEARCH, ACIA, PACE,

ACD, Arctic-CHAMP, Land–Shelf Interactions, the Fourth International Polar Year, and

others have permafrost research as one of the

critical elements of their science plans. The

Task Force recommends that all responsible

funding agencies review their interdisciplinary Arctic programs to ensure that permafrost research is appropriately integrated in

program planning and execution.

4.1.2 Lack of a Visible U.S. Federal

Research Program

The Task Force found no focused federal

research program dedicated to permafrost. The

National Science Foundation funds investigators in a wide range of disciplines and, under

the Office of Polar Programs (mostly through

its Arctic System Science Program), makes

awards in permafrost science. The two

components of GTN-P are examples of highly

successful research programs that have received

recent support from NSF. Another good

example is the development of a Permafrost

Observatory at Barrow by the International

Arctic Research Center, University of Alaska

Fairbanks. In past decades, particularly during

the Cold War and the construction of the DEW

Line and the Trans-Alaska Pipeline, CRREL and

USGS had viable and robust long-term research

programs on permafrost science and engineering. These once highly visible federal programs
no longer exist. The Task Force recommends

that the USGS, because of its key responsibilities in Alaska, should develop a long-term

permafrost research program with emphasis

on field programs. Recognizing DOD’s

responsibilities in the areas of contaminants

on formerly used defense sites and future

military construction in Alaska, the Task

Force recommends enhanced funding for

permafrost research and continued development of permafrost expertise at CRREL.

4.2 Data Collection, Protocols,

Monitoring, and Mapping

4.2.1 Standardized Collection of Basic

Environmental Parameters

Standardized collection of basic environmental parameters is essential to all scientific and

engineering endeavors in cold regions.

Effectively designed and implemented monitoring programs and sampling strategies provide

data that form the foundation upon which all

efforts ultimately depend. Moreover, the data

derived from such programs are invaluable for

modeling efforts (e.g., general circulation

models). The Task Force recommends that

the WMO GHOST (Global Hierarchical

Observing Strategy) hierarchical monitoring

scheme discussed in Chapter 2 be implemented in its current or a modified format in

permafrost monitoring programs. Effort should

be made to support the instrumentation deemed

necessary to collect basic data, in addition to

the information collected for process-based field

studies. At the lowest level of instrumentation,

air, near-surface, and upper-permafrost temperature measurements should be collected at subdiurnal frequencies. Complete meteorological

instrumentation at the higher end of the spectrum should include measurements of wind

speed and direction, insolation, surface albedo,

soil moisture, and snow cover thickness, and it

should include a dense vertical array of thermistors

extending from the soil surface, through the active

layer, and deep into the underlying permafrost.

The basic aspects of data collection at these

sites should be standardized (e.g., all air temperature measurements should be made at the

same height above the ground surface using a

standard radiation shield). Such sites should be

linked via satellite to provide real-time data to

users. Further, a concerted effort should be

made to assess the degree to which instrumented

sites are representative of the landscape. At

this scale, timely acquisition of current and historical remotely sensed imagery is essential. In

this way, a standardized set of basic environmental measurements, representative of a larger

region, can be collected and incorporated into a

spatially extensive data set that can serve the

needs of the national and international coldregions science and engineering communities.

4.2.2 Measurement Protocols

for Permafrost Monitoring

A specific set of measurement protocols

should be developed for monitoring permafrost

and closely related phenomena. The protocols

should be established by the scientific and engineering communities for the purpose of obtaining appropriate measurements at appropriate

spatial and temporal frequencies and resolution.

These protocols should cover the scale of

instrumentation, ranging from site to satellite.

Inherent in these protocols are the requisite

accuracy and precision of thermistors, optimal

depth of soil measurements, and requisite

ancillary data. This effort should be coordinated

and integrated with the GTN-P to ensure

collection of data useful for global climate

observation (Burgess et al., 2000; GTN-P web

site). Similarly, methods of monitoring activelayer thickness and thaw subsidence should be

integrated with those of ongoing international

projects (e.g., CALM, PACE) following discussion and any appropriate modification of those

protocols currently in place. In all cases, effort

should be made to assess the spatial variability

of thaw depth and soil temperature and to collect

ancillary data.

4.2.3 Permafrost Data Management

Data collected by federally funded permafrost projects should be archived in the Frozen

Ground Data Center at NSIDC within

appropriate time periods. Details about datacollection sites and meteorological and ground

36 Climate Change, Permafrost, and Impacts on Civil Infrastructure
measurements should be available in metadata

files with standardized formats. Some data

would be processed in accordance with identified and established user needs (e.g., modelers

and engineers may make better use of average

daily temperatures or accumulated degree-days

of freezing, thawing, heating, and cooling rather

than hourly air temperatures). Spatially intensive measurements, such as satellite imagery

or thaw depths collected on a regular grid,

should be available in a format conducive to

generation of descriptive statistics and rapid

mapping. Ultimately, these data will become part

of an international cold regions environmental

data directory with links to other databases.

4.2.4 NSIDC Frozen Ground Data Center

A recent initiative at the National Snow and

Ice Data Center (NSIDC) in Boulder has been

to archive permafrost and seasonally frozen

ground data (for example, borehole data, Arctic

Coastal Dynamics program data, and maps and

soils data from Russia and China). These

activities are partially funded by the International Arctic Research Center at the University

of Alaska Fairbanks. The data activities are an

outgrowth of the International Permafrost

Association’s data rescue program, the Global

Geocryological Database. Long-term funding

for the Frozen Ground Data Center is required.

Recognizing that NSIDC is funded primarily

by NOAA, the Task Force strongly recommends that additional funding be provided

by both NOAA and USGS to fully develop

and sustain the Frozen Ground Data Center

(an estimated $300,000 annually is required

for adequate support).

4.2.5 Baseline Permafrost Mapping

The Task Force recommends that U.S. and

international funding be sought to update

the International Permafrost Association’s

Circum-Arctic Map of Permafrost and Ground

Ice Conditions (Brown et al., 1997), using the

most recent international databases and

maps. In addition, the Task Force recommends the funding and production of a highresolution permafrost map for Alaska, a critical requirement for the state’s future with

regard to climate change. Federal and state

agencies and, potentially, the private sector

should jointly fund this effort (USGS; Army

Corps of Engineers, Alaska District; Alaska

State agencies; and industry). The evolving

Arctic Coastal Dynamics (ACD) program, a

joint effort of the IASC and IPA, could also be

a vehicle for facilitating data collection and

mapping of coastal erosion and flooding regimes.

A continuing research theme should be the

integration of existing permafrost maps with

elements of Arctic infrastructure, using GCMs

and GIS. These products should include new

information on the distribution and properties of

offshore and alpine permafrost.

4.2.6 Measurement Technologies

and Remote Sensing

Typical measurements for the different

hierarchies of permafrost sites are provided in

Section 2.3. Measurements range from probing

the active layer once annually to observing soil

temperature approximately hourly; annual to

semi-annual permafrost temperatures have also

been taken at 100-m depths. A fully instrumented

single site for examining temporal variability would

include measurements of soil temperature, soil

moisture, active-layer thickness, thaw settlement, and near-surface permafrost temperatures. Air temperature, wind speed, precipitation,

and snow depth are also high-priority measurements. With the exception of soil moisture, offthe-shelf instrumentation can make these measurements automatically and relatively

inexpensively. Presently, data are typically

recorded on a datalogger downloaded during

an annual visit to the site. Retrieval of data by

satellite uplink would mitigate the need for large

data storage capacity on-site and would allow

sites to be monitored in near-real time. A critical

instrumentation issue that needs to be addressed

is the development of advanced technology for

monitoring soil moisture. The Task Force recommends support for the development of

instrumentation for sensors in cold-regions

terrain by NSF’s Office of Polar Programs

and Directorate of Engineering and by NASA.

Satellite remote sensing offers the greatest

opportunity for large-scale monitoring of the

Chapter 4. Findings and Agency Recommendations 37
state of ground. The capability of current

sensors for permafrost monitoring needs to be

fully evaluated and exploited, as the study of

permafrost by satellites has been a low-priority

issue in the remote sensing community. The

Task Force recommends that NASA continue

development of new satellite sensors optimized for monitoring state of the surface,

temperature, moisture, and ground ice in

cold regions. A greater capability to detect

ground ice would have additional planetary

applications. All remote sensing techniques will

require thorough field validation. Until reliable

permafrost sensors become available, methods

that combine remotely sensed data with groundbased measurements and soil thermal modeling

should be developed and tested. Further, much

can be inferred about permafrost from combining digital elevation measurements (DEMs) with

other remotely sensed parameters such as those

concerning snow cover and vegetation. However, the DEMs currently available for much of

Alaska are extremely coarse and sometimes

inaccurate, limiting their utility. The Task Force

recommends support for advanced studies

involving synthesis of remotely sensed data

with other data sets, including model output.

4.2.7 Monitoring and Analysis Requirement

The Task Force recommends a new

approach (via federal legislation) for funding

the monitoring of cold-regions environments

in which federal projects are planned. Federal agencies that fund all or portions of

major public works (in excess of $1M in

cost) in Alaska should specify that 1% of

the project planning, design, and construction costs for future Alaskan projects be

invested in monitoring in the vicinity of the

construction site. In this way climate change

can be more adequately monitored and observations analyzed and mapped into the future.

4.3 Basic Permafrost Research

4.3.1 Process Studies

in Permafrost Research

Transfer functions: air–surface–permafrost, snow, vegetation. Quantitative estimation of the air–surface–permafrost transfer

function remains a significant problem, because

of non-linearity in the near-surface layer (air,

snow, vegetation) and because of numerous

feedback effects. Continued basic research on

these processes is critical if a complete understanding of arctic energy flows is to be achieved.

Carbon cycle considerations. Greenhouse

gases (carbon dioxide and methane) released

from thawing permafrost into the atmosphere

could create a strong positive feedback in the

arctic system, and this topic is under investigation

at several sites. Counterbalancing this prediction, there may be increased arctic ecosystem

plant productivity, which could enhance the

carbon sink (Kolchugina and Vinson, 1993). The

carbon cycle in the nearshore zone of the Arctic

Ocean has received less attention and requires

significant investigation. Key questions remain:

What is the major mechanism regulating the

distribution and associated rates of carbon transfer, transformation, and burial in the arctic land–

shelf system? How do biogeochemical

processes on the Arctic Ocean margins influence the chemistry and biology of surface waters

and associated fluxes of CO2 between the air–

water (or air–ice) interface? Answers to such

questions require much more research on the

state of offshore and onshore permafrost in the

atmosphere–land–shelf system in the Arctic.

Hydrology and hydrogeology. Although

Arctic hydrology has received serious attention

in many science planning documents, little

attention has been devoted to subsurface

hydrologic and hydrogeologic processes. This

is a critical omission because subsurface flow

and subsurface storage are extremely important in the arctic hydrological system and in the

arctic water cycle as a whole. Studies of permafrost hydrogeology are practically nonexistent

in the U.S., a serious gap in research for the

high Arctic and Subarctic. The Task Force

recommends that NSF’s new arctic programs,

Arctic-CHAMP and Land–Shelf Interactions,

fully incorporate permafrost hydrology and

hydrogeology in their science plans.

Permafrost degradation. Stratigraphic and

paleogeographic evidence indicates that permafrost will degrade if recent climate warming

38 Climate Change, Permafrost, and Impacts on Civil Infrastructure
continues. Degradation of ice-rich permafrost

has been documented under contemporary conditions in central Alaska and elsewhere

(Osterkamp and Romanovsky, 1999;

Osterkamp et al., 2000; Jorgenson et al., 2001).

Little is known, however, about specific

processes associated with the thawing of

permafrost, either as a function of time or as a

three-dimensional process affecting the geometry of permafrost distribution over a wide spectrum of geographic scale. There is urgent need

to conduct theoretical and numerical studies and

additional field investigations to address these

critical issues; stratigraphic and paleoclimatic

studies incorporating stable isotope dating should

be included, as has been done in the field of

glaciology.

Geomorphic investigations. The study of

landforms and geomorphic processes is a critical component of permafrost science but has

received little attention in Alaska in recent

decades. Process-based and modeling investigations focused on the evolution of slopes and

other geomorphic features are urgently needed.

Particular attention should be given to how processes interact over a spectrum of geographic

scale. Studies focused on landscape evolution

over extended periods are also critical and can

contribute to existing programs (e.g., SEARCH,

Arctic-CHAMP) concerned with hydrological

and sediment budgets over extensive areas.

Geomorphological studies should, where possible, employ a systems approach that combines

expertise from closely related disciplines.

4.3.2 Permafrost Modeling

Modeling is a powerful tool in permafrost

research. Although significant progress has been

achieved during the last three decades, the

importance of permafrost in a global context

has been underestimated. Until recently, GCMs

did not incorporate permafrost and permafrostrelated processes. The modeling community has

begun to understand that unless permafrost and

permafrost-related processes are incorporated,

there is little reason to expect that GCMs will

produce physically reasonable results for the

Arctic (Slater et. al., 1998a, b). Inclusion of

permafrost in GCMs is a major challenge to

both modelers and permafrost researchers, and

continued cooperative research between the

two communities is a necessity. Funding of

modeling efforts for arctic and subarctic regions

must require that permafrost be incorporated in

the research plans.

Another important issue related to GCMs is

how well they can predict the extent, duration,

and thickness of snow. Permafrost degradation

under a changing climate scenario is strongly

influenced by the regional snow cover. To date,

GCMs do not provide an adequate predictive

capability for snow.

Analytical models. Many methods have

been proposed to calculate active-layer thickness and mean annual permafrost surface temperatures using simplified analytical solutions

(Pavlov, 1980; Zarling, 1987; Romanovsky and

Osterkamp, 1995; Smith and Riseborough,

1996). For work involving point locations where

subsurface data are available, the importance

and utility of analytical solutions is diminished.

Numerical models are widely available for

permafrost problems and can be used with some

confidence when adequate information about

climatic, boundary layer, and subsurface parameters is available. Serious problems arise,

however, when complex models are employed

in a spatial context, particularly when little is

known about the spatial variability of parameters important to geocryological investigations.

In such cases, stochastic modeling (Anisimov

et al., 2002) or analytic procedures in a GIS

environment (Nelson et al., 1997; Shiklomamov

and Nelson, 1999; Klene et al., 2002) often yield

results superior to complex, physically based

models. Analytical equations can also be helpful in providing insights into the physics of the

coupling between permafrost and the

atmosphere. However, these simple equations

are presently limited in their usefulness because

they do not include the effects of inhomogeneous

active layers with multiple layers, variable

thermal properties, unfrozen water dynamics,

and non-conductive heat flow. Deterministic

models must be transformed to probabilistic

models if the risk of permafrost degradation is

to be assessed under a changing climate scenario (Bae and Vinson, 2001; Vinson and Bae,

Chapter 4. Findings and Agency Recommendations 39
2002). More research on refining analytical

models (both deterministic and probabilistic) for

use in permafrost environments is a necessity.

4.4 Applied Permafrost Research

4.4.1 Synthesis for Cold-Regions

Engineering Applications

Scientific research programs are not necessarily tailored to the needs of engineering

practice and design criteria development.

Predictions of frost effects and the behavior of

frozen ground are highly empirical and are based

on limited numbers of field and laboratory

investigations. Far-reaching assumptions are

necessary to arrive at any decisions regarding

changes to the natural pattern of warming or

cooling of foundations for buildings, roads, railways, or airstrips in a permafrost environment.

Engineers tend to rely a great deal on the proven

performance of past construction as essential

validations of analytical predictions.

In a period of accelerating global warming,

the recent past provides only partial guidance

for predicting future permafrost conditions.

Extrapolation of the recent air temperatures can

be misleading. The Task Force believes

decisions regarding new infrastructure on

permafrost will be more credible if they consider climate change, as predicted by global

circulation models, weighed by associated

probabilities.

A history of seasonal temperature is represented through freezing and thawing indices, the

annual sums of daily average temperatures

below or above freezing, respectively. Freezing

and thawing indices are translated to corresponding ground surface freezing and thawing

indices for general categories of ground surface

types, e.g., snow, turf, sand, and gravel. The

transfer of atmospheric heat energy into lower

layers of the soil is proportional to the soil thermal

conductivity, which varies with soil grain size,

dry density, water content, and water state

(frozen or unfrozen). More precise computations of heat transfer are possible but impractical

in all but carefully controlled research settings.

Alaskan records of air temperature are sparse,

and maps of soil characteristics are poorly

resolved. The Task Force recommends that

a denser network of environmental monitoring stations be funded by NOAA, USGS,

USDA, and responsible state agencies for

Alaska. Such a network of monitoring stations,

along with the application of GIS mapping

methods, will allow improved procedures to be

developed for predicting permafrost behavior

that can better account for natural variability

and probabilistic considerations.

4.4.2 Cold-Regions Design

Criteria Development

There is a significant requirement for a coldregions engineering database to enhance the

design, construction, and maintenance of infrastructure. Existing environmental atlases of

Alaska are nearly twenty years old. A new database should take advantage of GIS technology

and include geotechnical information, such as

permafrost distribution, soil type, and soil properties, as well as climatic information including

air temperature and snow depth. The system

should allow standard calculations for practical

engineering applications, such as freezing and

thawing indices, active-layer thickness, and soil

bearing capacity. There is also a need to establish a database or information clearinghouse on

existing cold-regions transportation infrastructure (design, construction, and operations).

Methods for site-specific forecasts of climate

change must be developed. A rational approach

to developing design criteria using GCM results

will perhaps be more affordable than applying

an arbitrarily large factor of safety to conventional design criteria. We cannot continue to treat

forecasts of future climate deterministically (i.e.

linearly extrapolating a rate of temperature

change over a future time interval at a given

location) and must move to a more probabilistic

approach. Adaptating conventional statistical

analyses of trends and extremes to apply GCMpredicted accelerated change is a challenging

topic for researchers.

4.4.2 Trans-Alaska Pipeline

System (TAPS)

In its 2001 Comprehensive Monitoring

Report (a series of three reports dealing with

40 Climate Change, Permafrost, and Impacts on Civil Infrastructure
TAPS operations, construction, and operation),

the Joint Pipeline Office (JPO) of the U.S. and

the State of Alaska indicated a range of

problems regarding changing permafrost. The

following conclusions were reached:

• The warming trends could have some effect

on the foundations of the elevated portions

of the pipeline, some 423 miles with 78,000

vertical support members (VSMs).

• More than 25,000 VSMs are currently

subject to movement. Of those VSMs having heat pipes (because they are located in

areas of warm permafrost), 84% have some

degree of blockage that could affect the

structure’s load-bearing capacity.

• A long-term maintenance and reconstruction program is necessary for the VSMs.

The pipeline owners and their operating consortium, Alyeska, have contracts underway to

determine the scope of the operating and maintenance program that will be necessary over

the next 30 years, the period requested for a

right-of-way renewal. The current lease expires

in 2004 for both the federal and state rights of

way.

When the present lease was issued, scientific

and engineering decisions were based on the

permafrost and climate regimes of the previous

three decades. Permafrost engineering applications were limited until World War II and

reached their peak during the construction of

the DEW Line from 1948 to 1962. The expertise of CRREL and the USGS was made available to the TAPS design team, which spent four

years working out the present design of the

VSMs. The Task Force recommends that a

similar effort be made today that closely

coordinates the efforts of the TAPS and JPO

with a significantly upgraded federal

research effort on permafrost. Linkages with

the Arctic Climate Impact Assessment (with its

Chapter 4. Findings and Agency Recommendations 41

secretariat at the University of Alaska Fairbanks)

should be established early in this effort.

4.4.3 Contaminants in

Permafrost Environments

Past practice favored burial of contaminants

in permafrost because it was assumed to be

impermeable and therefore a safe and effective method for isolating contaminated wastes.

Contaminants are mobile in the active layer,

however, and some can even be mobile within

frozen ground. Moreover, when permafrost

thaws, the ground becomes permeable, allowing contaminants to spread laterally and to reach

deeper unfrozen and frozen layers. The Arctic

contains a significant number of contaminated

sites; in Alaska DOD has responsibility for formerly used defense sites, some of which are

contaminated. To determine the extent of the

problem, sites known to be contaminated must

be assessed individually, identifying the contaminants as well as the physical characteristics of

the site. The potential for diffusion of contaminants will require an estimate of the impact of

regional climate warming on the specific sites.

To develop models to predict the transport of

contaminants, the hydrological connections

between the near-surface and deeper layers or

ground water systems must be established.

Research is also required on the chemical

interaction of contaminants with the thawed

soils, as well as on such mitigation techniques

as bioremediation. CRREL is the logical federal

laboratory for this research, and the University

of Alaska (Fairbanks and Anchorage campuses)

has experienced research groups in this field.

The Task Force recommends substantially

increased federal funding for contaminants

research in cold regions by DOD, EPA, and

NSF, as this research is deemed critical to

the Nation’s cleanup effort in Alaska.
42 Climate Change, Permafrost, and Impacts on Civil Infrastructure

U.S. Geological Survey

(Department of the Interior)

• Develop a long-term permafrost research program

with emphasis on field work and monitoring of deep

boreholes; formulate the program as a contribution to

SEARCH.

• Adopt the WMO GHOST hierarchical monitoring

program for environmental data collection for new

boreholes and mapping.

• Jointly fund with NOAA the Frozen Ground Data

Center at NSIDC.

• Participate in joint funding of a high-resolution permafrost map of Alaska.

• Fund (with NOAA, USDA, and state agencies) a

denser network of environmental monitoring stations

for Alaska.

• Provide technical expertise (on permafrost and other

cold-regions issues) to the TAPS JPO during the rightof-way renewal process.

• Develop jointly with the Minerals Management

Service a study of offshore undersea permafrost.

• Expand stratigraphic investigations and mapping of Quaternary permafrost in Alaska and the contiguous states.

• Expand investigations of periglacial landforms and processes (both contemporary and relict) in Alaska and

the contiguous states.

U.S. Army Corps of Engineers

(Department of Defense)

• Provide enhanced funding for permafrost research

and support the continued development of permafrost

expertise at CRREL.

• Participate in joint funding of a high-resolution permafrost map of Alaska.

• Increase funding for research on contaminants in cold

regions at CRREL.

• Plan for climate change and permafrost degradation

at existing and new military facilities to be built in

Alaska.

• Rescue past agency data and contribute present and

future data to national archives.

• Expand the role of the National Permafrost Test Site

[a node in the National Geotechnical Experimentation Sites (NGES) network] on Farmer’s Loop Road

outside Fairbanks.

National Science Foundation

• Review all interdisciplinary arctic programs to ensure

that permafrost research is appropriately integrated

in program planning and execution.

• Within the Office of Polar Programs, restructure the

Glaciology program under the heading Cryosphere,

which would include snow, ice, and permafrost.

• Adopt hierarchical, spatially oriented monitoring

strategies (preferably variants of the WMO/GHOST

approach) as appropriate for all arctic research

programs.

• Fund proposals for the development of instrumentation for sensors in cold regions (e.g., an autonomous

soil moisture sensor) (Office of Polar Programs and

Directorate of Engineering).

• Incorporate permafrost hydrology, hydrogeology, and

geomorphology in arctic programs such as ArcticCHAMP and SEARCH; incorporate permafrost

research in global carbon programs.

• Increase support for research on permafrost-related

geomorphic processes and terrain/landform analysis.

• Increase support for geocryological hazards research

at local, regional, and circumpolar scales.

• Increase funding for proposals dealing with research

on contaminants in cold regions.

• Support international permafrost activities, including

conferences and workshops.

• Integrate the use of the Permafrost National Test Site

at Fairbanks into U.S. Arctic research logistics

planning.

• Include permafrost research at the Barrow Global

Climate Change Research Facility.

National Aeronautics and Space Administration

• Continue the development of satellite sensors

optimized for monitoring the state of the surface,

temperature, moisture, and ground ice in cold regions.

• Explicitly include geocryological applications in competitive grants programs concerned with the use of

satellite remote sensing data.

• Include the development of frozen ground sensors in

NASA contributions to SEARCH.

• Support the Barrow Global Climate Change Research

Facility as a satellite sensor validation site; use the

facility to ground-truth satellite frozen ground sensors.

Federal Agency, State of Alaska, and National Research Council Recommendations
Chapter 4. Findings and Agency Recommendations 43

National Oceanic and Atmospheric Administration

(Department of Commerce)

• Jointly fund with USGS the Frozen Ground Data

Center at NSIDC.

• Jointly fund with USGS, USDA, and the State of

Alaska a denser network of environmental monitoring stations around Alaska.

• Adopt the WMO GHOST hierarchical monitoring

program for environmental data collection.

Environmental Protection Agency

• Increase funding for research on contaminants in cold

regions, and fully develop a program in Alaska.

• Make funding available for permafrost-related

hazards research, particularly in urban areas.

U.S. Forest Service

(Department of Agriculture)

• Increase the number of soil moisture and temperature monitoring stations in Alaska.

• Formalize and extend existing programs in soil physics

and carbon sequestration.

U.S. Natural Resources Conservation Service

(Department of Agriculture)

• Refine and extend activities devoted to characterizing, classifying, and mapping cryosols in Alaska and

the contiguous states.

• Formalize and extend existing programs related to

carbon sequestration in tundra regions of Alaska and

the contiguous states.

• Formalize and extend existing programs investigating

soil physics and ground temperature in Alaska, the

western cordillera of the contiguous states, and the

northern Appalachians.

State of Alaska

• Review the arctic engineering certification process

for knowledge of permafrost under changing climate

conditions.

• Seek federal support for test programs for nonstandard pavements for roads and airport runways.

• Review building codes with a view to near-term

changes in the permafrost regime.

• Intensify and extend geological and geophysical

investigations of permafrost and its role in Quaternary

history by the Division of Geological and Geophysical Surveys (DGGS).

• Survey community infrastructure located in permafrost environments, with specific emphasis on rural

sewage and ground water systems.

National Research Council

(National Academies of Science and Engineering)

• Have the Transportation Research Board (TRB), in

cooperation with the Polar Research Board (PRB),

develop a proposal for a study on the impacts of changing permafrost on transportation systems in Alaska.

• Have the Polar Research Board (PRB) include global permafrost monitoring and research in the U.S.-

supported programs for the International Polar Year,

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56 Climate Change, Permafrost, and Impacts on Civil Infrastructure
Most of the definitions given below were

taken from the Multi-Language Glossary of

Permafrost and Related Ground-Ice Terms

(van Everdingen, 1998). This source should be

consulted for more extensive definitions.

Updates, modifications, or new definitions are

indicated by inclusion of additional references.

Active layer

The layer of ground subject to annual

thawing and freezing in areas underlain by

permafrost.

Active-layer detachment slide

Shallow landslides that develop in permafrost areas, involving reduction in effective

stress and strength at the contact between

a thawing overburden and underlying frozen

material. Active-layer detachment slides

can occur in response to high seasonal air

temperature, summer rainfall events, rapid

melting of snowcover, or surface disturbances. See Lewkowicz (1992).

Active-layer thickness

The thickness of the layer of ground subject

to annual thawing and freezing in areas

underlain by permafrost (Also see thaw

depth). See Nelson and Hinkel (2003).

Alas

A large depression of the ground surface

produced by thawing of a large area (e.g.,

> 1 ha) of very thick and exceedingly icerich permafrost.

Cryoturbation

(a)A collective term used to describe all soil

movements due to frost action.

(b)Irregular structures formed in earth

materials by frost penetration and frost

action processes, and characterized by

folded, broken, and dislocated beds and

lenses of unconsolidated deposits, included

organic horizons, or bedrock.

Degree-day

A derived unit of measurement used to

express the departure of the mean temperature for a day from a given reference

temperature. Also see freezing index and

thawing index.

Depth of zero annual amplitude

The distance from the ground surface

downward to the level beneath which there

is practically no annual fluctuation in ground

temperature.

Excess ice

The volume of ice in the ground that exceeds

the total pore volume that the ground would

have under natural unfrozen conditions.

Freeze–thaw cycle

Freezing of material, followed by thawing.

The two fundamental frequencies involved

are diurnal and annual.

Freezing index

The cumulative number of degree-days

below 0oC for a given time period (usually

seasonal).

Frost action

The process of alternate freezing and thawing of moisture in soil, rock, and other

materials, and the resulting effects on

materials and on structures placed on or in

the ground.

Frost creep

The net downslope displacement that

occurs when a soil, during a freeze–thaw

cycle, expands perpendicular to the ground

surface and settles in a nearly vertical 

direction.

Glossary
Frost heave

The upward or outward movement of the

ground surface (or objects on or in the

ground) caused by the formation of ice in

the soil.

Frost mound

Any mound-shaped landform produced by

ground freezing, combined with accumulation of ground ice due to groundwater

movement or migration of soil moisture. Also

see Nelson et al. (1992).

Frost penetration

The movement of a freezing front into the

ground during freezing.

Frost-susceptible soil

Subsurface earth materials in which segregated ice will form (causing frost heave)

under the required conditions of moisture

supply and temperature.

Frozen ground

Soil or rock in which part or all of the pore

water has turned into ice.

Gas hydrate

A special form of solid clathrate compound

in which crystal lattice cages or chambers,

consisting of host molecules, enclose guest

molecules.

Gelifluction

The slow downslope flow of unfrozen earth

materials over a frozen substrate. Also see

solifluction.

Geocryology

The study of earth materials and processes

involving temperatures of 0oC or below.

Geothermal gradient

The rate of temperature increase with depth

below the ground surface.

Ground ice

A general term referring to all types of ice

contained in freezing and frozen ground.

High-center polygon

An ice-wedge polygon in which melting of

the surrounding ice wedges has left the

central area in a relatively elevated position.

Ice lens

A dominantly horizontal, lens-shaped body

of ice of any dimension.

Ice segregation

The formation of discrete layers or lenses

of segregated ice in freezing mineral or

organic soils, as a result of the migration

and subsequent freezing of pore water.

Ice wedge

A massive, generally wedge-shaped body

with its apex pointing downward, composed

of foliated or vertically banded, commonly

white, ice.

Ice-wedge polygon

A network of ice wedges defining the

boundaries of a geometric polygon in plan

view.

Intrusive ice

Ice formed from water injected into soils

or rocks.

Latent heat of fusion

The amount of heat required to melt all ice

(or freeze all pore water) in a unit mass of

soil or rock. For pure water this quantity is

334 J g–1.

Low-center polygon

An ice-wedge polygon in which thawing of

ice-rich permafrost has left the central area

in a relatively depressed position.

58 Climate Change, Permafrost, and Impacts on Civil Infrastructure
Mass wasting (mass movement)

Downslope movement of soil or rock on or

near the earth’s surface under the influence

of gravity.

Massive ice

A comprehensive term used to describe

large masses of ground ice, including ice

wedges, pingo ice, buried ice, and large ice

lenses.

Mean annual air temperature (MAAT)

Mean annual temperature of the air, measured at standard screen height above the

ground surface.

Mean annual ground-surface temperature

(MAGST)

Mean annual temperature at the surface of

the ground.

Mean annual ground temperature (MAGT)

Mean annual temperature of the ground at

a specified depth.

N-factor

The ratio of the freezing or thawing index

at the ground surface to that derived from

air temperature records.

Palsas

Permafrost mounds ranging from about 0.5

to about 10 m in height and exceeding about

2 m in average diameter, comprising (1)

aggradation forms and (2) degradation

forms. The term “palsa” is a descriptive

term to which an adjectival modifier prefix

can be attached to indicate formative

processes. See Washburn (1983) and

Nelson et al. (1992).

Patterned ground

A general term for any ground surface

exhibiting a discernibly ordered, more or less

symmetrical, morphological pattern of

ground and, where present, vegetation.

Periglacial

The conditions, processes, and landforms

associated with cold, nonglacial environments, regardless of proximity to past or

present glaciers.

Permafrost

Earth materials that remains continuously

at or below 0oC for at least two consecutive years.

Permafrost, continuous

Regions in which permafrost occurs nearly

everywhere beneath the exposed land

surface. At the circumpolar scale the term

continuous permafrost zone refers to a

broad area, crudely conformable with

latitude, in which permafrost is laterally continuous. See Nelson and Outcalt (1987).

Permafrost, discontinuous

Regions in which permafrost is laterally

discontinuous owing to heterogeneity of

material properties, subsurface water, and

surface cover.

Permafrost, dry

Permafrost containing neither free water

nor ice.

Permafrost, ice-rich

Permafrost containing excess ice.

Pingo

A perennial frost mound consisting of a core

of massive ice produced primarily by injection of water, and covered with soil and

vegetation.

Retrogressive thaw slump

A slope failure resulting from thawing if icerich permafrost.

Seasonally frozen ground

Ground that freezes and thaws annually.

Glossary 59
Solifluction

A general term referring to the slow downslope flow of saturated unfrozen earth

materials over an impermeable substrate

(also see gelifluction).

Thermokarst terrain

Irregular topography resulting from the

melting of excess ground ice and subsequent thaw settlement.

Thaw depth

The instantaneous depth below the ground

surface to which seasonal thaw has penetrated (also see active-layer thickness).

See Nelson and Hinkel (2003).

Thaw lake

A lake whose basin was formed or enlarged

by thawing of frozen ground. See Hopkins

(1949) and Washburn (1980, p. 271).

Thaw settlement

Compression of the ground due to loss of

excess ground ice and attendant thaw consolidation.

Thawing index (DDT)

The cumulative number of degree-days

above 0oC for a given time period (usually

seasonal).

Thaw consolidation

Time-dependent compression resulting from

thawing of ice-rich frozen ground and subsequent draining of excess water.

Thermal erosion

Erosion of ice-bearing permafrost by the

combined thermal and mechanical action

of moving water.

Thermal conductivity

The quantity of heat that will flow through

a unit area of a substance in unit time under

a unit temperature gradient. In permafrost

investigations thermal conductivity is usually

expressed in W m–1 oC–1.

Thermal offset

Temperature depression in the upper layer

of permafrost, resulting from the combined

effects of seasonal differences of thermal

conductivity and the operation of nonconductive processes in the active layer. See

Williams and Smith (1989) and Nelson et

al. (1985).

Zero curtain effect

Persistence of a nearly constant temperature very close to the freezing point of water

during annual freezing (and occasionally

thawing) of the active layer. See Outcalt et

al. (1990).

60 Climate Change, Permafrost, and Impacts on Civil Infrastructure
ACD

Arctic Coastal Dynamics (IASC)

ACIA

Arctic Climate Impact Assessment

ADOT&PF

Alaska Department of Transportation and

Public Facilities

ALT

active-layer thickness

ARCSS

Arctic System Science program (NSF/

OPP)

Arctic-CHAMP

Community-wide Hydrological Analysis and

Monitoring Program (U.S. National Science

Foundation initiative)

BEO

Barrow Environmental Observatory

CALM

Circumpolar Active Layer Monitoring

program

CEON

Circumarctic Environmental Observatories

Network

CRREL

Cold Regions Research and Engineering

Laboratory (U.S. Army Corps of Engineers)

DGGS

Division of Geological and Geophysical

Surveys (Alaska Department of Natural

Resources)

DOD

U.S. Department of Defense

EPA

U.S. Environmental Protection Agency

FAO

Food and Agriculture Organisation (of the

United Nations)

FGDC

Frozen Ground Data Center (NSIDC)

GCOS

Global Climate Observing System

GCM

general circulation model (or global climate

model)

GHOST

Global Hierarchical Observational Strategy

(WMO)

GIS

geographic information systems (or geographic information science)

GSC

Geological Survey of Canada

GTN-P

Global Terrestrial Network for Permafrost

GTOS

Global Terrestrial Observing System

IASC

International Arctic Science Committee

ICSU

International Council of Scientific Unions

IPA

International Permafrost Association

IPCC

Intergovernmental Panel on Climate Change

List of Acronyms
IPY

International Polar Year

JPO

Joint Pipeline Office (U.S. federal and State

of Alaska)

LTER

U.S. Long Term Ecological Research

Network

MAAT

mean annual air temperature

MAGST

mean annual ground surface temperature

MAGT

mean annual ground temperature

NASA

U.S. National Aeronautics and Space

Administration

NOAA

U.S. National Oceanic and Atmospheric

Administration

NRCS

U.S. Natural Resources Conservation

Service (USDA)

NSF

U.S. National Science Foundation

NSIDC

U.S. National Snow and Ice Data Center

(Boulder, Colorado)

OPP

Office of Polar Programs (U.S. National

Science Foundation)

PACE

Permafrost and Climate in Europe program

SEARCH

Study of Environmental Arctic Change

(U.S. federal government multiagency

initiative)

TAPS

Trans-Alaska Pipeline System

TDR

time-domain reflectometry

TEMS

Terrestrial Ecosystem Monitoring Sites

network

TOPC

Terrestrial Observational Panel for Climate

UAF

University of Alaska Fairbanks

UNEP

United Nations Environment Programme

UNESCO

United Nations Educational, Scientific and

Cultural Organization

USACE

U.S. Army Corps of Engineers

USDA

U.S. Department of Agriculture

USPA

U.S. Permafrost Association

USARC

U.S. Arctic Research Commission

USGS

U.S. Geological Survey

VSM

vertical support member

WMO

World Meteorological Organization

62 Climate Change, Permafrost, and Impacts on Civil Infrastructure
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 conducting special studies such as Climate Change, Permafrost, and Impacts on Civil

Infrastructure. USARC biennially submits a strategic document, Goals and Objectives 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, Anchorage, Alaska 99501.

USARC COMMISSIONERS (DECEMBER 2003)

George B. Newton, Jr.

Fairfax, Virginia (Chair)

Mary Jane Fate

Fairbanks, Alaska

John F. Hobbie, Ph.D.

Woods Hole, Massachusetts

Duane H. Laible, PE

Seattle, Washington

John R. Roderick

Anchorage, Alaska

Susan F. Sugai, Ph.D.

Fairbanks, Alaska

Mead Treadwell

Anchorage, Alaska

Rita R. Colwell, Ph.D.

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.