Case Study

Pintail duck photo by Peter LaTourette

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Some plants and animals in alpine lakes
above treeline may disappear locally as
treelines move higher and lakes warm.

Global warming could reduce populations
of ducks and other waterfowl that breed
in the prairie pothole region of the north-
central United States and south-central
Canada.

PRO^e°

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Melting Glaciers,
Changing Ecosystems

The glaciers in Glacier National Park are
shrinking. Today, the park's largest glaciers
are only about a third of the size they were
in 1850, and many small mountain glaciers
have disappeared completely during the
past 150 years. The area of the park
covered by glaciers declined by 73 percent
from 1850-1993. The cause? A regional
warming trend that some scientists believe
may be related to global climate change.
Since 1900, Glacier National Park's average
summer temperatures have increased by
about 1.8 degrees Fahrenheit.

Park visitors can experience the scale of
glacial retreat by hiking the trail to Upper
Grinnell Lake, where a series of signs mark
the former end points of Grinnell Glacier.
The glacier once covered 576 acres on the
eastern slope of the Continental Divide. To
reach its terminus today, one must climb
steadily upward through an area that was
covered with ice in the 1850s. Still farther
uphill is the sign marking the terminus in
the 1930s, still higher the 1960s, and finally
the 1980s. Today the remnants of Grinnell
Glacier—one of more than 50 mountain
glaciers in the park—are reached just below
the summit of Mt. Gould. The glacier has
shrunk by more than 62 percent since 1850
and now covers barely 200 acres.

If scientists' predictions are accurate,
Grinnell and all of the park's other glaciers
will disappear entirely within the next
30 years.

Melting glaciers are only part of the story.
Experts believe that climate change will
have wide-ranging impacts on fish,
wildlife, trees, and plants throughout the
western mountains and plains.

In some areas, a warmer climate could
cause streams to become too warm to
support trout, salmon, and other cold-
water fish. If mountain snowpacks decline,
summer soils and vegetation may become
drier, increasing the risk of fire. Changes in
stream flow and water temperature also
could affect insects and other invertebrates
that live in streams and rivers, with
repercussions up the food web on fish,
amphibians, and waterfowl.

Climate change may affect agriculture in
the plains states, the heart of the nation's
breadbasket. It also may affect ducks and
other waterfowl by increasing the severity

and frequency of drought in the continent's
major duck breeding area—the prairie
potholes and parklands of the north-central
United States and south-central Canada.

Another hazard—forest fire—may occur
more frequently in Yellowstone National
Park if the climate becomes drier. Fire
frequency depends on local weather, sources
of fuel and ignition, and the effectiveness of
fire suppression. Climate change also could
reduce the abundance of whitebark pines
and army cutworm moths, two favored
foods of grizzly bears. Whitebark pines
already are in decline, primarily due to a
fungus known as white pine blister rust.

If the region's climate continues to warm in
the future, forests of lodgepole pine and
western cedar in Glacier National Park may
gradually be replaced with forests dominated
by spruce and western hemlock. Treelines are
expected to move upslope at a rate of
roughly 350 feet for every degree Fahrenheit
of warming. Alpine meadows may be
invaded by fir trees, and rare alpine plants
may disappear locally as conditions change.

"It's increasingly hard to understand why it's called Glacier
National Park, because the glaciers are getting hard to find."

— Bruce Babbitt, Secretary of the Interior
October 7, 1998

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Case Study — Western Mountains and Plains

A History of Change

The western mountains and plains always
have been subject to major natural
disturbances such as fires, avalanches,
landslides, windstorms, floods, droughts,
and pest invasions. It would seem like the
region's plants and wildlife would be able
to handle a gradual change like global
warming.

But fires and floods are short-term events.
Long-term changes in average conditions,
such as those caused by global warming,
exert very different forces on ecosystems.
For example, an overall warming may
allow low-elevation plants and animals to
move upslope and invade habitats
currently occupied by high-elevation
species. Changing conditions may benefit
some species more than others, causing

What is Global Warming?

The Earth's climate has changed in the past, and will continue to change naturally in the future. Ice ages,
long warm periods, and short-term fluctuations in temperature and precipitation are all elements of
the global climate's natural variability.

Today, the average global temperature is rising. Is that natural? Some of the temperature increase can
be explained by natural factors. But many scientists believe that a portion of the warming trend may be
caused by humans. Human activities are creating a buildup of greenhouse gases—primarily carbon
dioxide, methane, and nitrous oxide—in the atmosphere.The heat-trapping property of these gases is
undisputed. Although scientists do not know exactly how the Earth's climate responds to increases in
greenhouse gases, they do know that the current warming trend is consistent with changes that would
be expected from the increase in greenhouse gases.

Scientists generally believe that the burning of fossil fuels and other human activities are the primary
reason for the increased concentration of carbon dioxide in the atmosphere. Fossil fuels burned to run
cars and trucks, heat homes and businesses, and power factories are responsible for almost 99 percent
of U.S. anthropogenic carbon dioxide emissions and about 20 percent of our nitrous oxide emissions.
Of the carbon dioxide emissions, industrial activity accounted for 33 percent in 1997. Personal and
commercial transportation accounted for 30 percent, and residential and commercial energy use
accounted for 19 and 16 percent, respectively. Increased agriculture, deforestation, landfills, industrial
production, and mining also contribute a significant share of carbon dioxide, methane, and other
greenhouse gas emissions.

Average global temperatures at the Earth's surface have increased 0.6-1.2°F since the late 19th century.
The 10 warmest years in the 20th century all occurred in the last 15 years. Snow cover in the northern
hemisphere,floating ice in the Arctic Ocean, and the areas covered by mountain glaciers have all
decreased. Globally, sea level has risen 4-10 inches during the past century. Worldwide precipitation
over land has increased by about 1 percent, and the frequency of extreme rainfall events has increased
throughout much of the United States.

Although it is impossible to predict future changes in climate with certainty, many scientists believe
that the continued addition of greenhouse gases to the atmosphere is likely to raise the Earth's average
temperature by several degrees in the next 100 years. Rising global temperatures are expected to raise
sea level and change precipitation and other local climate conditions. Changing regional climate could
alter forests, crop yields, and water supplies. It also could threaten human health and harm birds, fish,
and many types of ecosystems.

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the composition of natural communities to
change. A single fire may make no
noticeable long-term change in an
ecosystem. But if conflagrations become
more frequent, fire-adapted trees such as
lodgepole pine, Douglas fir, and western
larch may become more common and
expand their range in areas such as
Yellowstone National Park.

Although dramatic changes in climate have
occurred in the Earth's past, and some of
the current global warming trend may be
natural in origin, many scientists believe
that the world will warm more rapidly
during the next 100 years than it has at
any time in the past 10,000 years. That
rate of change may have significant effects
on natural ecosystems and individual plant
and animal populations.

What Can Be Done?

To address the threat of climate change,
first we have to understand the risks. The
potential impacts of climate change also
should be considered within the context of
other stresses that affect natural areas
today, such as invasive species, pollution,
and habitat loss.

Scientists currently are analyzing how
climate change might affect natural
ecosystems in many national parks and

preserves, including Glacier, Yellowstone,
Olympic, and North Cascades National
Parks.

Prevention of human-induced climate
change also is an important strategy. Some
global warming probably will occur no
matter what we do, because some of it is
natural. But also, humans have become
dependent on fossil fuels. The burning of
fossil fuels emits greenhouse gases, which
may remain in the atmosphere for years,
decades, or even centuries, exacerbating
the natural warming. But we as individuals
can take action now to reduce our own
consumption of fossil fuels by improving
energy efficiency and using alternative
energy sources. (See "Searching for
Solutions" on page 7 and "What People Can
Do" on page 8.)

Glacier National Park

Today's climate may be too warm to
sustain the park's mountain glaciers long-

term. Researchers estimate that even if
average temperatures were to remain at
their current level, all the glaciers would
disappear within the next 100 years. If
warming in the region proceeds as
expected, the glaciers will be gone much
sooner, probably by the year 2030.

The size of the park's glaciers already is
affected by changes in climate. For
example, the glaciers retreated dramatically
from 1920-1940, when the region
experienced above-average summer
temperatures and below-average annual
precipitation. From 1960-1979,
temperatures dropped, precipitation
increased, and some of the larger glaciers
actually grew slightly. Since that time the
glaciers have receded farther.

Glacier National Park is not the only area
where glaciers are melting. Mountain
glaciers in the Alps, south-central Alaska,
and the Pacific Northwest also have
retreated over the past century.

"Glacier's ecosystem has already altered
in response to climate change."

— Daniel Fagre, Research Ecologist

U.S. Geological Survey, Glacier Field Station

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In addition to the melting glaciers, a
warmer climate could cause declines in
snow cover, reductions in trout
populations, the loss of rare alpine plants,
and changes in forest composition in
Glacier National Park.

The park has a wide range of habitats and
climatic conditions that are responsible for
the area's rich biological diversity.
Mountains rise abruptly from the prairies,
and the east and west sides of the
Continental Divide exhibit a sharp contrast
in climate. The park includes soils that are
rich in calcium as well as soils that are
calcium-poor, each supporting a very
different community of plants and animals.
Various parts of the park contain plants that
are typical of the northern Rocky
Mountains, the Great Plains, the Pacific
Northwest, boreal regions, and Arctic-alpine
regions. Each of the three major river
systems in the park (Missouri, Columbia,
and Saskatchewan) also has its own distinct
aquatic community.

Global warming could lead to many
complex changes in the park's plant and
animal communities, including shifts in the
treeline and changes in stream and lake
communities. Such changes have occurred
naturally during past climatic changes and
will occur naturally in the future. The
difference is that now humans may be

increasing the pace and magnitude of
climate change.

Yellowstone National Park

Global warming may result in a warmer
and drier climate in the Yellowstone
region, increasing the risk of forest fires.
Some computer models project a warmer
and wetter climate, but the trend over the
20th century was toward warm and dry.

Since the massive fires of 1988, when
nearly half of Yellowstone National Park
burned, scientists who study the area have
paid close attention to climate change. The
number of fires and their severity depends
on many factors other than climate, such
as fuel management practices (e.g.,
prescribed burns and the thinning of
forests) and the effectiveness of fire
suppression efforts. But climate and
weather clearly play a role. Experts agree
that the fires of 1988 came about as result
of a winter drought, a hot dry summer,
and unusually strong winds.

Also important were the large areas of
highly flammable, old-growth lodgepole
pine forest. Under normal conditions, large
fires like those of 1988 occur only once in
every few generations. But with
approximately 40 percent of Yellowstone
still vulnerable to large-scale burns, any

Fish in the Future

Imagine casting a line into the Flathead River at Glacier
National Park and not finding any trout. Or picture a
fly fisherman revisiting the Madison River in Wyoming
in the future and catching only half the cutthroat trout
of today. This kind of scenario could become reality
sometime in the next 100 years.

A recent EPA study found that a moderate warming of
4.5°F over the next 70 years could cut the habitat of
brook, rainbow, and cutthroat trout by one-fourth to
one-third nationwide, with similar habitat losses for
chum, chinook, pink, and coho salmon. Habitat losses
are not evenly distributed around the country. For
example, rainbow trout habitat is projected to decline by
only 9 percent in Washington, whereas Pennsylvania,
New York, Ohio, Indiana, and Illinois collectively lose
86 percent of their baseline habitat for rainbow trout.
When added to existing threats such as whirling disease
and other exotic diseases, climate change could be
stressful for many cold-water fish.

Cutthroat trout, rainbow trout, and other fish in the
trout and salmon family require cold water. These fish,
and the cold-water invertebrates they feed on, could
lose habitat as the climate becomes warmer. The loss of
mountain glaciers, warmer air temperatures, reductions
in winter snowpack, and changes in the timing and rate
of spring snowmelt could make many streams too
warm for cold-water fish.

Streamflows altered by changes in rainfall and snowfall
could affect fish populations. The young of some species
of native trout hatch in summer when snowmelt is
declining, while others hatch in spring before runoff
occurs. Warmer winters could increase the occurrence of
rain falling on snow, which may harm incubating eggs of
trout that spawn in the autumn.

Changes in streamflow and temperature may affect
insects and other invertebrates that live in streams and
are important food sources for fish. In the McDonald
Basin of Glacier National Park, for example, the
distribution of six species of caddisfly larvae in streams
is closely related to water temperature. If water
temperatures change, the variety and abundance of
invertebrates living in stream water are likely to
change as well.

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Ducks in Peril

From 50 to 80 percent of North America's ducks and
other waterfowl nest in the prairie pothole region of
the north-central United States and south-central
Canada. The shallow prairie wetlands are vulnerable to
drought, and computer models indicate that global
warming is likely to bring stronger and more frequent
droughts to the prairie pothole region.

According to one study, global warming could cause
the number of prairie ponds in the north-central United
States that hold water in the spring to drop from
today's average of 1.3 million to just 0.6-0.8 million by
the year 2060. The loss of habitat could reduce the
average number of ducks settling to breed in the north-
central United States from 5 million birds today to
between 2.1 and 2.7 million by the year 2060.

Duck populations reached historical lows in the 1980s
due to a combination of prolonged drought, the loss
and degradation of habitat, and land use changes that
favored predators. In recent years, better water
conditions and intensive wetland conservation and
management programs have helped duck populations
rebound.

When the prairie potholes dry up during drought years,
waterfowl normally move north to nest in the parkland
potholes of Alberta and Manitoba —pothole wetlands
that are surrounded by aspens and willows. But
researchers have found that many parkland potholes
also may dry up in the future as the climate changes,
leaving ducks with fewer potential nesting sites.

What can be done to protect the pothole region from
the potential effects of global warming? Scientists
recommend that we start by conserving the least
drought-sensitive areas so they are available to birds in
the future as the climate warms.

increased fire risk due to climate change
could pose a significant problem.

Fire plays an important role in several
ecosystems in the region, including
sagebrush steppe, western juniper
woodlands, and ponderosa pine forests. In
the past, frequent low-intensity surface fires
perpetuated ponderosa pine stands with
grassy undergrowth. Today, after 60 years
of policies to prevent and suppress forest
fires, many ponderosa and lodgepole pine
forests have high densities of trees, are
plagued by epidemics of insects and diseases,
and are subject to severe fires that can
destroy entire stands of trees. The trees' high
density could lead to more frequent and
more damaging outbreaks of defoliating
attacks by western spruce budworms. Insect
outbreaks have occurred many times in the
past, but fire suppression policies and
climate change may exacerbate them in the
future. The replacement of old-growth
forest stands by younger stands could affect
some of the park's plant and bird species,
such as the northern twinflower, fairy
slipper, pine martin, and goshawk.

Even a modest warming and drying could
reduce the habitat of whitebark pine by up to
90 percent within 50 years. Whitebark pine
populations already are declining because of
the white pine blister rust fungus and other
invasive exotic pests. Whitebark pine nuts
and army cutworm moth caterpillars, which
are found in these forests, provide vital food

for the region's grizzly bear population.
Whitebark pine forest may be replaced with
Douglas fir, and on the lower slopes, forest
would give way to treeless landscapes
dominated by big sagebrush, Idaho fescue,
and bluebunch wheatgrass.

Climate change also could cause high
alpine ecosystems to shrink in many areas.
Local extinctions of alpine species such as
arctic gentian, alpine chaenactis, rosy
finch, and water pipit could be expected as
a result of habitat loss and fragmentation.

Parks in the
Pacific Northwest

The impacts of climate change in North
Cascades, Mt. Rainier, and Olympic
National Parks may be similar to those
affecting Glacier National Park. If the
regional climate follows the global trend
toward warming, scientists expect receding
glaciers, warmer stream waters, changes in
plant and animal communities, and
increased risk of fire.

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North Cascades
National Park

North Cascades National Park contains
more than 300 glaciers, accounting for
approximately a third of all the glaciers in
the lower 48 states. Since the end of the
Little Ice Age in the late 1800s, glaciers
have retreated throughout the park area.
Although historical data on the glaciers'
size are scant, scientists believe that
several dozen glaciers may have
disappeared during that time.

Warmer temperatures and disappearing
glaciers could harm the five species of
salmon —sockeye, pink, coho, chum, and
chinook—that rely on rivers in the park.
Some streams in the North Cascades can
support salmon only because the streams
are fed by glacial meltwater. Salmon in the
region already face immediate stresses
from human activities outside the park.

Olympic National Park

Above the old-growth temperate
rainforest, the high alpine and subalpine
meadows of Olympic National Park come
alive with wildflowers every spring. Future
hikers may experience only a fraction of
today's colorful displays, as some meadows

may give way to forests moving upslope in
response to changing climate.

Fire, the length of the growing season, and
soil moisture are among the factors that
determine the growth and distribution of
alpine and subalpine plants. All of these
natural processes are sensitive to climate
change, and changes in any of them could
produce conditions favorable for trees to
invade the meadows.

In fact, changes already are occurring at
the treeline: Forest species are beginning to
crowd the edge of the meadows and fill the
gaps of open grassland. Furthermore,
computer simulations suggest that in the
future, a warmer climate will allow trees to
become established in all current meadows.

Mt. Rainier National Park

The size of glaciers on Mount Rainier has
fluctuated significantly over time. For
example, during the last ice age, from
about 25,000 to about 15,000 years ago,
glaciers covered most of the area now
within the boundaries of Mount Rainier
National Park and extended to the
perimeter of the present Puget Sound
Basin. The glaciers retreated after the last
ice age, but advanced again between the
14th century and 1850.

From 1850 to 1920, the mountain's
glaciers gradually retreated, with the
melting accelerating after 1920. Many of
the major glaciers advanced again from the
1950s through the early 1980s in response
to relatively cooler temperatures and high
snowfalls in the region. Since the early
1980s, many glaciers in the park have been
thinning and retreating again. How they
will fare in the future depends on regional
changes in climate, which may be affected
by global warming.

Searching for Solutions

To address the threat of global warming,
governments and organizations in the
states that contain the national parks of
the western mountains and plains could
improve the health and resiliency of natural
ecosystems, prepare for a changing climate,
and work to limit future global warming by
reducing greenhouse gas emissions.

Conservation biologists note that, in most
cases, park boundaries cannot be expanded
to continue protecting species that leave
the area as the climate changes. They
recommend that governments and
nonprofit agencies establish wildlife
habitat corridors to connect parks with
other protected habitats for plants and
wildlife. Corridors could be designed to

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Case Study — Western Mountains and Plains

u

What People Can Do

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allow protected species to shift their range
if their habitat changes.

If personnel in parks and other protected
areas worked with scientists to come up
with long-term management plans and
strategies, then together they could
mitigate the future impacts of global
warming in protected areas. Efforts to
control invasive non-native plants and
animals, prescribed burning programs that
help prevent devastating conflagrations in
times of drought, and programs to monitor
species and habitats at risk are examples of
methods parks could employ to continue
to protect their resources as the climate
changes. The additional stresses posed by
climate change must be considered and
managed in the context of existing
environmental impacts and changes.

We all add greenhouse gases to the atmosphere whenever we use energy from fossil fuels. Residential
energy use accounted for 19 percent of overall C02 emissions from the combustion of fossil fuels in
1997, and motor vehicle use accounted for approximately 20 percent. Here are a few actions that peo-
ple can take to reduce their emissions.

Use mass transit, carpool with friends, or ride a bike whenever possible.

When it's time to replace the family vehicle, consider one that gets more miles per gallon than your
present vehicle.

When it's time to replace an appliance, look for the Energy Star® label identifying
energy-efficient models.

¦	When buying or building a new house, an Energy Star model gives greater quality and comfort as
well as lower monthly costs. For more information, go to the Energy Star Homes web site,
www.epa.gov/homes.

Buy products that feature reusable, recyclable, or reduced packaging to save the energy required to
manufacture new containers and reduce greenhouse gas emissions from landfills.

¦	Encourage your company to join EPA programs such as Energy Star Buildings*" and Waste Wi$e
recycling programs, and to buy office equipment with the Energy Star label.

Plant trees, which absorb carbon dioxide from the air.

Educate others. Let friends and family know about these practical, energy-saving steps they can
take to save money while protecting the environment.

Encourage scientific research and public discussion on global warming and solutions such as
energy efficiency and alternative energy.

Slowing Climate Change

Today, action is occurring at. every level to
reduce, avoid, and better understand the

risks associated with global warming.
Many cities and states across the country
have prepared greenhouse gas inventories,
and many are pursuing programs and

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policies that will result in reductions of
greenhouse gas emissions.

At the national level, the federal
government is working in partnership with
businesses, states, and localities to address
global warming while also strengthening
the economy. In addition, the U.S. Global
Change Research Program coordinates the
world's most extensive research effort on
climate change.

For More Information

The U.S. Environmental Protection
Agency's global warming site includes
detailed information on climate change,
impacts, and actions.

www.e pa .gov/g lobalwarming/

Diagrams showing how Glacier National
Park's Sperry, Grinnell, and Swiftcurrent
glaciers have receded over time are
available on the web.

www. mesc. usgs.gov/
glac7glacier_retreat.htm

EPA's state-specific climate change fact
sheets include information on potential
impacts in the western mountains and
plains states.

www.e pa .gov/g lobalwarming/
impacts/stateimp/

¦ The latest U.S. National Assessment of
Climate Variability and Change gives a
detailed report on the potential effects of
global warming in the United States.

www.nacc.usgcrp.gov/

Animation illustrating the predicted
impact of climate change in Glacier
National Park to the year 2100.

http://nrmsc.usgs.gov/research/
glacier_model.htm

"We should be thinking in terms of what will be here
for the 22nd century and the 23rd. We will have
dishonored our legacy if we are not prepared to protect it,
preserve it, and pass it on to succeeding generations."

— Robert G. Stanton, Director, National Park Service, August 12, 1999

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