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 lobal climate change will cause major changes in natural
ecosystems and the plants and animal communities that make up
these ecosystems across the United States, according to a report
released by the Pew Center on Global Climate Change.
 The
report describes the very real possibility that global warming
will disrupt the integrity of many of the terrestrial ecosystems
on which we depend -- ecosystems that provide humans such valuable
goods and services as foods, raw materials, recreational opportunities,
clean air and water, and erosion control. The importance of ecosystems
extends beyond economics and tangible benefits, with many people
placing a high value on the spiritual and aesthetic role nature
plays in their lives. Despite the crucial roles of terrestrial
ecosystems, they are increasingly threatened by the impacts of
a growing human population, through habitat destruction and air
and water pollution, and now as a result of global climate change.
"This
report describes how climate change is likely to profoundly alter
the natural environment," said Pew Center President Eileen
Claussen. "It underscores the point that domestic and international
action to deal with climate change is needed sooner rather than
later."
The report
was commissioned by the Pew Center and written by two ecologists,
Dr. Jay R. Malcolm of the University of Toronto and Dr. Louis
F. Pitelka of the University of Maryland Center for Environmental
Science. Among the authors' conclusions:
- As the earth warms, the distribution of terrestrial
ecosystems will change as plants and animals follow the shifting
climate. For example, the eastern United States will likely lose
many of its deciduous forests as climate zones shift northward.
Thus, sugar maples, so much a part of northeastern states such
as Vermont, are likely to be replaced by oaks. Likewise, some
habitats -- such as those found in the high elevations in mountainous
regions of the West -- are likely to shrink in a warming world.
- Both the amount and rate of anticipated warming
pose threats to the nation's biological diversity. The rate of
anticipated climate change is estimated to be ten times that
seen in the last Ice Age. As a result, certain species may face
dwindling numbers and even extinction if they are unable to migrate
fast enough to keep up with the changing climate.
- Climate change is likely to alter the quantity
and quality of the various goods and services that ecosystems
provide. For example, climate change is likely to affect the
ability of ecosystems to filter air and water pollutants and
to control soil erosion.
- Modeling studies estimate that the productivity
of plants could change little or could increase substantially.
However, these productivity changes will not be uniform and some
regions could see declines. While productivity may rise, so could
decomposition and, with it, the release of carbon to the atmosphere.
- The effects of climate change on ecosystems
must be considered in the context of a range of human-caused
impacts on ecosystems. Overall, the new threat of climate change
is likely to be especially damaging for ecological communities
and species that have suffered the greatest disruption from human
development. Natural ecosystems already under stress because
of air and water pollution will have diminished capacity to adapt
to climate change. Likewise, habitat destruction and fragmentation
will lessen the chances that species will successfully migrate
to more suitable climates and habitats.
- It is important to remember that ecosystems
are inherently complex, and our ability to predict how ecosystems
will respond to climate change is limited. This uncertainty will
limit our ability to anticipate and minimize the effects of climate
change on ecosystems. In order to maximize nature's own capacity
to adapt, government officials and community leaders should continue
to support efforts to conserve biodiversity and protect natural
systems.
A complete
copy of this report and other Pew Center reports can be accessed
from the Pew Center's web site, www.pewclimate.org.
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The
Pew Center was established in May 1998 by the Pew Charitable
Trusts, one of the United States' largest philanthropies and
an influential voice in efforts to improve the quality of the
environment. The Pew Center is a nonprofit, nonpartisan and independent
organization dedicated to providing credible information, straight
answers and innovative solutions in the effort to address global
climate change. Eileen Claussen, the former US Assistant Secretary
of State for Oceans and International Environmental and Scientific
Affairs, leads the Pew Center.
The
Pew Center includes the Business Environmental Leadership Council,
a group of large, mostly Fortune 500 corporations all working
with the Pew Center to address issues related to climate change.
The companies do not contribute financially to the Pew Center;
it is solely supported by contributions from charitable foundations.
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