U.S. ENVIRONMENTAL

PROTECTION AGENCY

Office of Policy (2171)

401 M Street, SW Washington, DC 20460

Printed on Recycled Paper

Climate

Change and

BIRDS

Change On The Wing

Climate

Change and

BIRDS

Change On The Wing

WHAT CAN YOU DO? ■ Inform yourself and other. To keep 

up with the latest scientific developments, check out EPA’s 

climate change website at 

www.epa.gov/globalwarming. Or 

call EPA’s National Service Center for 

Environmental Publications (NSCEP) 

at 1-800-490-9198 and ask for 

information on climate change.

■ Encourage more research. If you work for 

an organization that carries out related 

scientific studies, suggest including a 

climate change component to the research.

■ Reduce greenhouse gases. Use a more 

fuel-efficient (or non-motorized) mode of transportation. Carpool. Purchase 

electronic devices and appliances with the

ENERGY STAR® label. Plant trees

.

United States EPA-236-F-99-003

Environmental Protection

Agency May 1999

Office of Policy (2171)

CLIMATE CHANGE AND ECOSYSTEMS Thousands of scientists predict

that the earth’s climate will

change because human activities

are altering the chemical composi-

tion of the atmosphere through

the buildup of greenhouse gases.

The heat-trapping property of such

gases as carbon dioxide, methane,

nitrous oxide, and chloroflurocar-

bons is undisputed. Greenhouse

gases are released into the atmos-

phere in large quantities by

motorized vehicles, utilities, facto-

ries, appliances, and landfills. 

Although there is uncertainty

about exactly how and when the

earth’s climate will respond to

higher concentrations of green-

house gases, observations indi-

cate that detectable changes are

underway. Temperatures will

most likely rise by an average of

2 to 6 ̊F over the next century,

along with measurable changes

in precipitation, soil moisture,

and sea level. All of these

changes could have adverse

effects on many ecological sys-

tems, as well as on human

health and the economy.
CLIMATE CHANGE AND BIRDS

Global warming could affect the

abundance and distribution of birds

in the United States. Changes in climate may change nesting and feeding

habitats, migratory stopover areas,

and the availability of key food

sources. Some impacts may be positive, making conditions more favorable for certain kinds of birds. But

climate change also could lead to

reduced breeding success in some

species and some localities, raising

the possibility of regional population

declines and extinctions.

Birds require specific environmental

conditions to survive and raise their

young. Nesting, for example, is timed

to coincide with favorable weather

and food availability. If a trend

toward warmer spring weather leads

birds to nest earlier, their breeding

success may suffer if primary food

sources are not yet available when

nestlings hatch.

Birds are more mobile than most

other animals, and they simply can

fly to a new location if a former site

is no longer suitable. But global

warming may make it difficult for

some species to find new habitats.

Plant and animal communities that

provide optimal habitat today may be

fundamentally altered in the future as

the climate changes. A recent study

suggests that ecological communities

may not simply shift their range

northward in response to warming,

but instead may undergo complex

changes as interacting species are

affected in different ways by the

changing climate.

Changes in temperature and precipitation predicted under global warming could affect the nesting habitats

of ducks and other waterfowl. According to one study, global warming could

cause breeding populations of ducks in

the north-central United States to

decline by more than half—from 5 million birds today to between 2.1 and

2.7 million by the year 2060. 

Why? Warmer temperatures and more

frequent droughts could cause hundreds of thousands of ponds in the

prairie pothole region of the northcentral U.S. to dry up. The potholes

account for only 10 percent of North

America’s waterfowl breeding habitat,

but they produce 50 to 80 percent of

the continent’s ducks. The pothole

region also serves as an important

stopover point for migrating waterfowl. Although many of the affected

ducks may move north into Canada,

studies suggest that climate change

may affect breeding habitats in

Canadian prairies and forests as well.

Populations of sooty shearwaters off

the coast of California and Washington

declined by 90 percent between 1987

and 1994, a period when sea surface

temperatures increased. The decline

represents a potential loss of more

than 4 million birds. The warmer water

triggers a reduction in upwelling, a

circulatory process that brings nutrient-rich water to the ocean’s surface.

Over the past two decades, reduced

upwelling apparently has caused a 70

percent decrease in zooplankton, a key

food source for shearwaters and the

small fish that the shearwaters eat.

CLIMATE CHANGE AND WATERFOWL

AND SEABIRDS