laska spans an area nearly a fifth the size of the entire lower 48 states,and

includes a wide range of physical, climatic,and ecological diversity in its

rainforests,mountain glaciers,boreal spruce forest,and vast tundra,peatlands,

and meadows. It contains 75% by area of US national parks and 90% of wildlife

refuges,63% of wetlands,and more glaciers and active volcanoes than all other

states combined. Direct human pressures on the state's land environment are

light,but pressures on its marine environment from large commercial fisheries

are substantial. Lightly populated (614,000 people) and growing about 1.5%

per year,Alaska has the nations' highest median household income,with an

economy dominated by government (44% of incomes) and natural resources

(oil 35%, fisheries 7%). Diverse subsistence livelihoods,practiced primarily by

native communities,depend on fish,marine mammals,and other wildlife,and

play a social and cultural role vastly greater than their contribution to monetary

incomes.

Observed Climate Trends

laska has warmed substantially over the 20th centur y, particularly over the

past few decades. Average warming since the 1950s has been 4°F (2°C).

The largest warming, about 7°F (4°C),has occurred in the interior in winter.

The growing season has lengthened by more than 14 days since the 1950s.

Some records suggest that much of the recent warming occurred suddenly

around 1977. Alaska has also grown wetter recently, with precipitation over

most of the state increasing 30% between 1968 and 1990. The observed warming is part of a larger trend through most of the Arctic corroborated by many

74

KEY ISSUES

• Permafrost Thawing and

Sea Ice Melting

• Increased Risk of Fire

and Insect Damage to

Forests

• Sensitivity of Fisheries

and Marine Ecosystems

• Increased Stresses on

Subsistence Livelihoods

“Everything is Tied to

Everything Else”

A Lesson from Alaska

Caleb Pungowiyi is a Yupik Eskimo who

lives in the Arctic, moving back and forth

from Alaska to Siberia in pursuit of walrus

and other sea mammals. Gathering food

directly from the land and the sea makes

the Yupiks very careful observers of what is

going on around them. In recent years they

have noticed, for example, that winters are

warmer, that the walrus are looking thinner

and their blubber is less nutritious, and that

they have had to go further and further from

shore to reach the ice pack where young

seals are being fed fish caught by their parents. The Yupiks have even noticed that

some killer whales have begun eating sea

otters, an unusual shift in their diet apparently brought on by the reduced number of

fish and seals. But are all of these changes

connected, and, if so, what do they portend

for the future?

Satellite observations confirm that the sea

ice retreat noticed by the Yupiks is happening much more widely, as temperatures

warm over most of the Arctic region.

ALASKA

A

A

Observed Temperature Observed Precipitation

Over the 20th century, average temperature and precipitation in Alaska have both increased.
independent measurements of sea ice,glaciers,permafrost, vegetation,and

snow cover. In contrast to other regions,the most severe environmental stresses in Alaska at present are climate-related.

Scenarios of Future Climate

odels project that rapid Arctic warming will continue. For Alaska,the

Hadley and Canadian models project 1.5-5°F (1-3°C) more warming by

2030,and 5-12°F (3-6.5°C) (Hadley) or 7-18°F (4-10°C) (Canadian) by 2100. The

warming is projected to be strongest in the north and in winter. Both models

also project continued precipitation increases in most of the state reaching 20-

25% in the north and northwest,with areas of up to 10% decrease along the

south coast. Projections indicate that increased evaporation from warming will

more than offset increased precipitation,however, making soils drier throughout most of the state.

75

For Alaska, the Hadley and

Canadian models project 1.5-

5°F (1-3°C) more warming by

2030, and 5-12°F (3-6.5°C)

(Hadley) or 7-18°F (4-10°C)

(Canadian) by 2100.

Because the edge of the sea ice is further

out to sea in deeper water, walrus – which

rest on the ice and feed on the bottom –

must dive deeper to feed and find less food,

causing their weakened condition. Because

sea ice is melting back earlier in the year,

the seal pups being raised on the edge are

smaller when they must leave the ice, worsening their chance of survival. With fewer

seal pups, sea otters become an alternative

food source for whales. Because a favorite

food of sea otters is sea urchins, fewer sea

otters will mean more sea urchins. Sea

urchins' favorite food is the kelp that provide the breeding grounds for the fish, so

more sea urchins will mean less kelp and

thus fewer fish. And with walrus and seal

populations declining, it is these very fish

that the Yupik need more than ever to feed

themselves.

It may seem like only a little warming in a

very cold place, but for the Yupiks, the

warming is significantly disrupting their traditional food sources because as Caleb

Pungowiyi says, in their environment, like

all environments, “everything is tied to

everything else.”

M

Precipitation Change - 21st Century Temperature Change - 21st Century

Canadian Model

Both models project precipitation

increases of up to

25%. Despite

these increases,

the projected rise

in air temperature

is expected to lead

to slightly reduced

soil moisture

throughout most

of Alaska.

100%

75%

50%

25%

0

-25%

-50%

-75%

-100%

Hadley Model 

Canadian Model

By 2100, both

models project

large increases in

annual average

temperature, with

the greatest

warming in the

North and West.

Hadley Model 

+15oF

+10oF

+5oF

0o

-5oF
76

Permafrost Thawing and 

Sea Ice Melting 

he rapid warming Alaska is

already experiencing is bringing

substantial ecological and socioeconomic impacts,many of which result

from thawing permafrost or melting

sea ice. Permafrost underlies most of

Alaska,and the recent several

decades of warming have been

accompanied by extensive thawing,

causing increased erosion,landslides,

sinking of the ground surface,and disruption and damage to forests,buildings,and infrastructure. Thawing is

projected to accelerate under future

warming,with as much as the top 30

to 35 feet (10 meters) of discontinuous permafrost thawing by 2100.

Warming is also likely to impair transport by shortening the seasonal use

of ice roads.

Sea ice off the Alaskan coast is retreating and thinning,with widespread

effects on marine ecosystems,coastal

climate,human settlements,and subsistence activities. The area of multiyear Arctic sea ice has decreased 14%

since 1978,with an apparent sharp

increase in the annual rate of loss in

the 1990s. Since the 1960s,sea ice

over large areas of the Arctic basin

has thinned by 3 to 6 feet (1 to 2

meters),losing about 40% of its total

thickness. All climate models project

large continued loss of sea ice,with

year-round ice disappearing completely in the Canadian model by

2100.

Retreat of sea ice allows larger storm

surges to develop,increasing the risk

of inundation and increasing erosion

on coasts that are also made vulnerable by permafrost thawing. In some

regions,shorelines have retreated

more than 1500 feet (400 meters)

due to erosion, over the past few

decades. Several Alaskan coastal villages will soon have to be fortified or

relocated. Loss of sea ice also causes

large-scale changes in marine ecosystems,threatening populations of

marine mammals and polar bears that

depend on ice,and the subsistence

livelihoods that depend on them. It

is possible that further retreat of sea

ice will also bring some benefits,

principally to ocean shipping and offshore oil exploration and extraction,

and will have major implications for

trade and national defense.

Adaptations: Adaptations to thawing

depend on the site.Minimizing surface disruption and heat transfer from

buildings can reduce local contributions to thawing.Selecting sites without ice-rich permafrost,where feasible,can reduce the likelihood of subsidence. Otherwise,structures’vulnerability to thawing can only be

reduced through such costly measures as building on very deep or

refrigerated piles,or alternatively by

stripping surface soil five years or

more in advance,in order to let thawing occur before construction.

Coastal settlements can be fortified or

moved inland,but these options are

likely to be expensive. No effective

protection is likely to be available for

forests or natural coastlines.

ALASKA KEY ISSUES

T

Projected Summer Sea Ice Change

Current Sea Ice Extent 2030 Sea Ice Extent 2095 Sea Ice Extent

Both models project substantial further retreat of sea ice through the 21st century, with complete

loss of summer Arctic sea ice in the Canadian model by 2095. Sea ice outputs were not available

for the Hadley scenario, but a reconstruction based on sea-surface temperature shows a 40 to 50%

loss of summer sea ice by the 2090s.

Canadian Model: an ice-free Arctic summer
77

Increased Risk of Fire and

Insect Damage to Forests

ne third of Alaska is covered by

forests that support subsistence livelihoods,recreation,and in

the southeastern part of the state, a

timber industry. Recent warming has

increased average growing degreedays by about 20% over the state,

apparently increasing productivity

where forests are not moisture limited (mainly on the southern coast),

but reducing productivity where they

are (in much of the interior). The climate increasingly favors expansion of

boreal forest into the tundra zone,

particularly on the Seward Peninsula.

Recent warming has also been

accompanied by unprecedented

increases in forest disturbances,

including insects, blow-downs and

fire. A sustained infestation of spruce

bark beetles,which in the past have

been limited by cold,has caused

widespread tree deaths over 2.3 million acres on the Kenai Peninsula

since 1992,the largest loss to insects

ever recorded in North America. At

the same time,increases in blowdowns from intense windstorms,and

in canopy breakage from the heavy

snows typical of warm winters may

have increased vulnerability of forests

to insect attack. Significant increases

in fire frequency and intensity, both

related to summer warming,have also

occurred. Simultaneously,the potential damage from forest fires has

increased due to a rapid increase in

dispersed human settlement in

forests. The projected further warming is likely to increase risk of both

fire and insect disturbances, even in

the near term. In the longer term,

large-scale transformation of landscapes is possible,including expansion of boreal forest into the tundra

zone,shifts of forest types due to fire

and moisture stress,northward

expansion of some commercially

valuable species, and the appearance

of significant fire risk in the coastal

forest for the first time since observations began. In present commercial

forests,management practices must

adapt to heightened fire and pest

risk,including potential interactions

between them. In the longer term,

there is some chance that northward

shift of forest productivity and commercially valuable species will hold

substantial opportunities for new

commercial timber development.

O

Alaska's fisheries, the largest in the nation, appear to

have shown substantial sensitivity to climate fluctuations over the 20th century.

Annual Area of Northern Boreal

Forest Burned in North America

0

2

4

6

8

10

12

14

16

18

20

Annual

10-year average

The Alaskan boreal forest is a small part of an enormous forest that extends

continuously across the northern part of North America. The average area of

this forest burned annually has more than doubled since 1970.

In the longer term, large-scale

transformation of landscapes is

possible, including expansion

of boreal forest into the tundra

zone, shifts of forest types due

to fire and moisture stress,

northward expansion of some

commercially valuable species,

and the appearance of significant fire risk in the coastal forest for the first time since

observations began.
Sensitivity of Marine

Ecosystems and Fisheries

he Gulf of Alaska and Bering Sea

support marine ecosystems of

great diversity and productivity, and

the nation's largest commercial fishery. In 1995,Alaskan fisheries landed

2.1 million tons ($1.45 billion worth),

representing 54% of the landings and

37% of the value of all US fisheries.

The productivity of these ecosystems

fluctuates with year-to-year and especially decade-to-decade climate variability. Some data suggest that climate fluctuations have caused

extreme regime shifts in these ecosystems several times since 1900,most

recently in the late 1970s and perhaps again in the 1990s. Salmon

stocks soared in 1977 and most

groundfish stocks a few years later,

while forage fish such as capelin and

herring declined sharply, bringing

subsequent declines in the seabirds

and marine mammals that feed on

them. These changes likely reflect

joint effects of climate fluctuations,

ocean circulation,and human harvesting. Consequently, while the effect of

projected climate change on these

ecosystems is likely to be large,little

is known of its specific character.

Adaptations: Potential adaptation

measures include reducing the specialization of the fisheries capital

equipment to particular species in

particular places,to increase the

industry’s robustness to potential

shifts in species’location and abundance;increasing the flexibility of

fishing regulations through such

measures as variable quotas or buybacks;and limiting other ecosystem

stresses such as marine pollution or

disruption of nursery grounds.

Increased Stress on 

Subsistence Livelihoods

ubsistence makes an important

contribution to livelihoods in

many isolated rural communities,

especially but not exclusively for

native peoples. Subsistence is practiced to gather food,but is also

important to health,culture,and identity. Alaska's 117,000 rural residents

collect about 43 million pounds of

wild food annually, equivalent to 375

pounds per person each year. In

some remote communities,the subsistence harvest is as high as 800

pounds per person. Fish comprise

60% of the wild harvest,but there is

substantial regional variation: west

78

ALASKA KEY ISSUES

Canadian Model 21st Centur y

Hadley Model 21st Centur y

Summer Soil Moisture Change

>100

+75

+50

+25

0

-25

-50

-75

-100

Habitats for wildlife, on land and in the

ocean, will come under increasing

pressure from vegetation shifts and sea

ice retreat.

The Hadley model projects increased

summer soil moisture in central Alaska

and decreases in the north and south,

while the Canadian model projects moderate decreases throughout the state.

Canadian Model 21st Centur y

Hadley Model 21st Centur y

Winter Maximum 

Temperature Change

The largest projected warming is in

winter, when both models show average daily-high temperatures increasing

more than 15oF over the northern half

of the state.

+15oF

+10oF

+5oF

0o

-5oF

T S
coast communities rely principally on

fish,while northern ones rely more

on marine mammals,and interior

ones on both fish and land mammals.

Present climate change already poses

serious harms to subsistence livelihoods. Many populations of marine

mammals,fish,and seabirds have

been reduced or displaced. Reduced

snow cover, a shorter river ice season,and thawing of permafrost all

obstruct travel to harvest wild food.

Retreat and thinning of sea ice,with

associated stress on marine mammal

and polar bear populations and

increased open-water roughness,have

made hunting more difficult,more

dangerous,and less productive. It is

possible that projected near-term climate changes will enhance certain

subsistence harvests,but in general

are likely to intensify present harms,

through further loss of sea ice,river

ice,and permafrost. In the longer

term,projected ecosystem shifts are

likely to displace or change the

resources available for subsistence,

requiring communities to change

their practices or move. Shifts in the

composition of tundra vegetation

may decrease nutrition available for

caribou and reindeer, while invasion

of the tundra by boreal or mixed forest is likely to curtail the range of

caribou and musk-ox.

Adaptations: Although subsistence

cultures have historically adapted to

climate variability by shifting practices and target species,subsistence

practices are now both hotly contested and extensively regulated,posing

challenges to traditional means of

adaptation. It is possible that projected climate change will overwhelm

the available responses,particularly

for communities that rely on marine

mammals. Some communities may be

forced to reduce their dependence

on the wild harvest,or relocate.

General measures to increase

incomes may mitigate some impacts,

on nutrition for example,but not the

cultural effects of lost subsistence

resources.

79

Simulated Vegetation Distribution

Current

Hadley Model 2090s

Tundra

Taiga / Tundra

Boreal Conifer Forest

Temperate Evergreen Forest

Temperate Mixed Forest

Tropical Broadleaf Forest

Savanna / Woodland

Shrub / Woodland

Grassland

Arid Lands

Under the Hadley scenario, the

MAPSS biogeography model

projects large-scale loss of tundra and taiga ecosystems as

forests expand north and west.

Likely consequences include

disruption of wildlife migration

and associated subsistence

livelihoods, as well as the

potential for large releases of

soil carbon.