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Environmental Science
A Study of Interrelationships
Twelfth Edition
Enger & Smith
Chapter 1
Environmental Interrelationships
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Environmental Interrelationships
Outline
 The Nature of Environmental Science
 Regional Environmental Concerns
 Summary
The Nature of Environmental Science
 Environmental science is interdisciplinary, and
includes scientific and social aspects of human
impact on the world.
• It is a mixture of traditional science, individual and
societal values, and political awareness.
 The natural world is organized into relational
units between organisms and their environment
called ecosystems. An ecosystem approach
requires consideration of these relational units. It
is the right approach because it looks at the
natural world in its natural state—without cultural
or political bias.
The Nature of Environmental Science
 Environment is
everything that affects
an organism during its
lifetime.
Environmental science
Interrelatedness Is a Core Concept
 The study of environmental science is so
interesting, frustrating, and challenging because
of the interrelatedness among seeming
unrelated factors.
 Tug on anything at all and you’ll find it
connected to everything else in the universe.
John Muir
 Charles Darwin proposed that seed production
in red clover was related to the number of cats in
the area.
Interrelatedness Is a Core Concept
 The reintroduction of wolves to Yellowstone
National Park has resulted in many changes.
 31 wolves were introduced in 1995.
 In 1996 there were about 320 wolves.
 The wolves have caused water flow changes in
the park, increases in willow and aspen trees, as
well as beavers, songbirds, foxes, certain
rodents, hawks, and owls.
 Coyote and elk have declined.
Interrelatedness Is a Core Concept
 The Yellowstone wolves are connected to social,
economic, and political realms of human activity.
 It was important to environmentalists and
biologists to restore the wolf to its former habitat.
 Ranchers could lose money if wolves killed
livestock.
 The farm lobby fought long and hard in congress
to prevent the reintroduction.
 A fund was developed to pay ranchers for cattle
killed by wolves.
An Ecosystem Approach
 An ecosystem is a region in which the organisms
and the physical environment form an interacting
unit.
 The task of an environmental scientist is to
recognize and understand the natural interactions
that take place, and to integrate these with the
uses humans must make of the natural world.
Political and Economic Issues
 Most social and political decisions are made with
respect to political jurisdictions.
 Environmental problems do not necessarily
coincide with artificial political boundaries.
• Air pollution in China affects air quality in the western
coastal U.S. and British Columbia, Canada.
• Air pollution in Mexico affects air quality in Texas.
• Acid rain in Canada caused by power plants in the U.S.
Political and Economic Issues
 International agencies such as the International
Joint Commission have major bearing on
environmental quality over broad regions.
• The International Joint Commission was established in
1909, in part, to protect boundary waters between the
U.S. and Canada.
• The Commission identifies areas of concern and
encourages the cleanup of polluted sites that affect the
quality of the Great Lakes and other boundary waters.
The Global Nature
of Environmental Concerns
 The first worldwide meeting of heads of state
directed toward the environment took place at the
Earth Summit formally known as(United Nations
Conference on Environment and DevelopmentUNCED) in Rio de Janeiro in 1992.
• Most countries at the conference signed agreements on
sustainable development and biodiversity.
The Global Nature
of Environmental Concerns
 In 1997, representatives from 125 nations met in
Kyoto, Japan for the Third Conference of the
United Nations Framework Convention on
Climate Change.
• The Kyoto Protocol is viewed as one of the most
important steps to date in environmental protection
and international diplomacy.
• To reduce the overall emissions of six greenhouse
gases: CO2, Chlorofluorocarbons, Methane, NOx
The Global Nature
of Environmental Concerns
 The Millennium Ecosystem Assessment was
completed in 2005.
• As the human population grows, it puts pressure on
the natural ecosystems of the world.
• Most ecosystems are being negatively affected.
• Food production has increased at the expense of soil
loss due to erosion, conversion of natural ecosystems
to managed systems, and overconsumption of water.
Regional Environmental Concerns
 Environmental problems are complex and
interrelated with issues specific to a given
region.
 A regional approach to solving environmental
problems is ideal.
• Development and logging in the Pacific Northwest
conflict with the survival needs of owls, grizzly bears,
and other species.
• In most metropolitan areas, the problem of
endangered species is purely historical, as the
construction of cities has destroyed previously
existing ecosystems.
Regional Environmental Concerns
Regions of North America
The Wilderness North
 Much of Alaska and
northern Canada can be
characterized as
“wilderness” — areas
with minimal human
influence.
• Much of this land is owned
by governments, so
governmental policies
have a significant impact.
The Wilderness North
 These areas have important economic values in
their trees, animals, scenery, and other natural
resources.
 Resource exploitation involves significant tradeoffs. These ecosystems are sensitive to insults and
take a long time to repair damage.
 In the past, many short-term political and economic
decisions failed to look at long-term environmental
implications.
 Today, politicians are more willing to consider the
scientific and recreational values of wilderness.
The Wilderness North
 Native peoples in this area are sensitive to
changes in land use or government policy that
would force changes in traditional ways of life.
 They have become increasingly sophisticated in
negotiating with state, provincial, and federal
governments to protect rights they feel they were
granted in treaties.
The Agricultural Middle
 The middle of North
America is dominated
by intensive
agriculture.
 Original, natural
ecosystems have
been replaced by
managed agriculture.
The Agricultural Middle
 Farmland has tremendous economic value.
• It is mostly private land.
• While governments cannot easily control what happens
on private lands, they can
– Encourage activities such as research.
– Grant subsidies to farmers to encourage the planting of certain crops.
– Develop markets for products.
The Agricultural Middle
 Managed agricultural land is a major nonpoint
pollution source.
• Tilling causes air pollution in the form of dust.
• Soil erosion causes siltation of rivers and other bodies
of water.
• Nutrients from fertilizers are washed into rivers and
encourage algae growth, lowering water quality.
• Fertilizers and pesticides may enter groundwater and
cause contamination.
The Dry West
The Dry West
 This term refers to areas where rainfall is
inadequate for agriculture, but adequate for
ranching and livestock production.
 Because much of the land in the western U.S. is
of low economic value, most is still the property
of the U.S. government.
 The government encourages its use by
providing low-cost water for livestock and
irrigation, and low-cost grazing rights. It also
encourages mining and other development.
The Dry West
 Water is an extremely valuable resource in this
region.
• As cities grow, conflict over water rights arises
between urban dwellers and ranchers and farmers.
– Increased demand for water will result in shortages and trade-off
decisions.
The Dry West
 Low population density areas have a wilderness
character.
• Conflict has developed between economic land
management for livestock vs. wilderness
preservation.
The Forested West
 Coniferous forests
dominate the Pacific
Northwest landscape.
 Government and
commercial timber
companies own large
sections of land.
 Historically, the
government sold much
of this timber at a loss.
The Forested West
 In 1993, the U.S. Forest Service was directed to
stop below-cost timber sales.
• Timber officials claim access to public land is necessary
for them to remain in business and support the
economy.
• Conservationists argue ecological and intangible values
outweigh economic values.
– Grizzly bear habitat could be significantly altered by logging.
– The northern spotted owl has become a symbol of conflict between
logging and preservation.
The Great Lakes and Industrial
Northeast
 The Great Lakes and
Northeast are dominated
by large metropolitan
complexes with large,
complicated resource
demands.
 Many older cities have
declined, leaving behind
abandoned sites and
environmental problems.
The Great Lakes and Industrial
Northeast
 Industrial use of the Great Lakes and East Coast
has resulted in contamination of the water with toxic
materials.
• These pollutants bioaccumulate in the food chain.
– Governments have advised consumers not to eat fish and shellfish from
these areas.
 Water generates recreational value.
• Much of the North American population is concentrated
here, so the economic value of water for recreational use
is high.
The Diverse South
 The South is a
microcosm of all other
regions.
 Extremely rapid
population growth in
some areas has led to
problems with
groundwater,
transportation, and
regulating the rate of
growth.
The Diverse South
 Poverty in some areas encourages state and
local governments to accept industrial
development at the expense of other values.
 Use of the coastline sometimes encourages
development in unwise areas.
Summary
 Environmental science involves science,
economics, ethics, and politics in arriving at
solutions to environmental problems.
 Because ecosystems do not coincide with
political boundaries, a regional approach to
solving environmental problems is ideal.
 Each region of the world has certain
environmental issues that are of primary
concern because of the mix of population,
resource use patterns, and culture.