Environmental Encyclopedia

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Environmental Encyclopedia 3

United Nations Environment Programme

these treaties were too restrictive for American businesses

and might damage the American economy. The United

States did, subsequently, sign the biodiversity treaty on June

4, 1993.

Many environmentalists went to Rio de Janeiro in-

tending to denounce United States intransigence. Even

Envi-

ronmental Protection Agency

chief William Reilly, head

of the United States delegation, wrote a critical memo to

his staff saying that the Bush administration was slow to

engage crucial issues, late in assembling a delegation, and

unwilling to devote sufficient resources to the meeting. New-

sweek magazine entitled one article about the summit: “The

Grinch of Rio,” saying that to much of the world, the Bush

administration represented the major obstacle to environ-

mental protection.

Not all was lost at the Rio de Janeiro meeting, however.

Important contacts were made and direct negotiations begun

between delegates from many countries. Great strides were

made in connecting poverty to environmental destruction.

Issues such as

sustainable development

and justice had a

prominent place on the negotiating table for the first time.

Furthermore, this meeting provided a unique forum for dis-

cussing the disparity between the rich industrialized northern

nations and the poor, underdeveloped southern nations.

Many bilateral—nation to nation—treaties and understand-

ings were reached.

Perhaps more important than the official events at

the remote and heavily guarded conference center was the

“shadow assembly,” or

Global Forum

of NGOs, held in

Flamingo Park along the beach front of Guanabara Bay.

Eighteen hours a day, the park pulsed and buzzed as thou-

sands of activists debated, protested, traded information, and

built informal networks. In one tent, a large TV screen

tracked nearly three dozen complex agreements being nego-

tiated by official delegates at Rio Centrum. In other tents,

mini-summits discussed alternative issues such as the role

of women, youth,

indigenous peoples

, workers, and the

poor. Specialized meetings focused on topics ranging from

sustainable energy to endangered

species

. In contrast to

Stockholm, where only a handful of citizen groups attended

the meetings and almost all were from the developed world,

more than 9,000 NGOs sent delegates to Rio de Janeiro.

There were over 700 from Brazil alone. The contacts made

in these informal meetings may prove to be the most valuable

part of the Earth Summit.

[William P. Cunningham Ph.D.]

ESOURCES

ERIODICALS

Haas, P. M., et al. “Appraising the Earth Summit: How Should We Judge

UNCED’s Success?” Environment 34 (October 1992): 6.

1437

Hildyard, N. “Green Dollars, Green Menace.” The Ecologist 22 (May/June

1992): 82–84.

Hinrichsen, D. “The Rocky Road to Rio.” The Amicus Journal 14 (Winter

1992): 15.

THER

French, H. After the Earth Summit: The Future of Environmental Governance.

World Watch Paper 107. Washington, DC: World Watch Institute, 1992.

United Nations Environment

Programme

Formed in 1973 after the

United Nations Conference on

the Human Environment

, the UN Environment Pro-

gramme (UNEP) coordinates environmental policies of vari-

ous nations, nongovernmental organizations, and other UN

agencies in an effort to protect the environment from further

degradation. Sometimes dubbed the “environmental con-

science of the UN,” UNEP describes its goal as follows: “to

protect the environment by distributing education materials

and by serving as a coordinator and catalyst of environmental

initiatives.”

Some of UNEP’s major areas of concern are the

ozone

layer, waste disposal, toxic substances, water and

air pollu-

tion

deforestation

desertification

, and energy resources.

The ways in which UNEP addresses these concerns can be

best seen in the various programs it oversees or administers.

The

Earthwatch

program—which includes Global

Envi-

ronmental Monitoring

System (GEMS);

INFOTERRA

; and

International Register of Potentially Toxic Chemicals

(IRPTC)—monitors environmental problems worldwide

and shares its information database with interested individu-

als and groups. UNEP’s Regional Seas Program seeks to

protect the life and integrity of the Caribbean, Mediterra-

nean, South Pacific, and the Persian Gulf. The

Interna-

tional Geosphere-Biosphere Programme

(IGBP) pro-

motes awareness and preservation of biogeochemical cycles.

The Industry and Environment Office (IEO) advises indus-

tries on environmental issues such as

pollution

standards,

industrial hazards, and clean technology.

In addition to administering these programs, UNEP

has also sponsored several key environmental policies in the

last few decades. For example they initiated the

Convention

on International Trade in Endangered Species of Wild

Fauna and Flora

(CITES),

Convention on the Conserva-

tion of Migratory Species of Wild Animals

, and the Vi-

enna Convention for the Protection of the Ozone Layer.

Most recently, UNEP was responsible for planning the 1992

United Nations Earth Summit

in Rio de Janeiro, Brazil.

UNEP is headquartered in Nairobi, Kenya. The orga-

nization is headed by Mostafa Kamal Tolba, who assumed

the position of Executive Director in 1976 after the departure

of Maurice Strong.

Environmental Encyclopedia 3

Upwellings

ESOURCES

RGANIZATIONS

United Nations Environment Programme, United Nations Avenue, Gigiri,

PO Box 30552, Nairobi, Kenya (254-2) 621234, Fax: (254-2) 624489/

90, Email: eisinfo@unep.org, <http://www.unep.org>

Upwellings

Upwellings are highly productive areas along the edges of

continents or continental shelves where waters are drawn up

from the ocean depths to the surface. Rich in nutrients, these

waters nourish algae, which in turn support an abundance of

fish and other aquatic life. The most common locations for

upwellings are the western edge of continents, such as Peru

and southern California in the Pacific, northern and south-

western Africa in the Atlantic, and around

Antarctica

In order for upwellings to occur, there must be deep

currents flowing close to the continental margin. There must

also be prevailing winds that push the surface waters away

from the coast—as the surface waters move offshore, the

cold, nutrient-rich bottom waters move up to replace them.

The Pacific upwelling near Peru is the result of the north-

ward flow of the cold Humboldt current and the prevailing

offshore wind pattern. Every seven to ten years, there is a

shift in the prevailing wind pattern off the shore of Peru, a

condition known as

El Nin

. The prevailing wind in the

eastern Pacific shifts direction, causing the cold Humboldt

current to be replaced by warm equatorial waters. This pre-

vents upwelling, and the

ecological productivity

of the

ocean in this area falls dramatically.

In oceans, the majority of nutrients sink to the sea

bed, leaving the surface waters poor in nutrients. In marine

ecosystems, the primary producers are microscopic plank-

tonic algae known as

phytoplankton

, and these are only

found in surface waters, where there is enough sunlight for

photosynthesis

. The lack of nutrients limits their growth

and thus the productivity of the entire system, and most open

oceans have the same low levels of ecological productivity as

tundra

desert

ecosystems. In upwellings, the water is

cold and oxygen poor but it carries a tremendous amount

nitrates

and

phosphates

, which fertilize the phytoplank-

ton in the surface waters. These producers increase dramati-

cally, showing high levels of net

primary productivity

, and

they become the foundation of a biologically rich and varied

oceanic food web, teeming with fish and bird life.

The high productivity of the upwelling area off Peru

supports one of the richest sardine and anchovy fisheries

in the world. In addition, the large population of seabirds

associated with the Peruvian upwelling deposit equally large

quantities of phosphate and

nitrogen

rich droppings called

guano

on rocky islands and the mainland. Until oil-based

1438

fertilizers were developed, Peruvian guano was the principle

source for agricultural fertilizers.

In the Antarctic upwelling zone, the nutrient-rich wa-

ters support food webs at the base of which are massive

populations of large marine shrimp, called

krill

. These inver-

tebrates support a wide array of squid,

whales

seals

, pen-

guins, cormorants, boobies, and sea ducks. Commercial fish-

eries in the Antarctic upwelling zone are now exploiting the

krill harvest, an act which endangers all of the members

of this unique and complex cold-water food web. See also

Commercial fishing

[Neil Cumberlidge Ph.D.]

ESOURCES

OOKS

Ainley, D. G., and R. J. Boekelheide. Seabirds of the Farallon Islands: Ecology,

Dynamics, and Structure of an Upwelling-System Community. Stanford: Stan-

ford University Press, 1990.

Glantz, M. H., and J. D. Thompson. Resource Management and Environ-

mental Uncertainty: Lessons from Coastal Upwelling Fisheries. New York:

Wiley, 1981.

Uranium

Uranium is a dense, silvery metallic element with the highest

atomic mass of any naturally occurring element. It is the

forty-seventh most abundant element in the earth’s crust.

All of the isotopes of uranium are radioactive, which accounts

for a portion of the

background radiation

that is a natural

part of the

environment

. In the 1930s, scientists discovered

that one

isotope

of uranium, uranium-235, could be fis-

sioned, or split. This information brought about a revolution

in human society. The potential for

nuclear fission

is dem-

onstrated by the fact that it has made possible not only the

world’s most destructive weapons, but also the generation

of energy in a new way. Regardless of the purpose for which

it is used, nuclear fission has created severe waste disposal

problems which the world is struggling to solve. See also

High-level radioactive waste; Nuclear power; Nuclear weap-

ons; Radioactive waste; Radioactivity

Urban contamination

In urban areas where there has been extensive reshaping

of the land surface, disturbance from building and road

construction, land-filling, and additions of a variety of

chem-

icals

and minerals, there are many sources, causes, and types

of urban contamination. Urban contamination is of concern

from two perspectives: when new land is developed that was

previously under agriculture or other rural

land use

, and

when the central core industrial areas are redeveloped.

Environmental Encyclopedia 3

Urban contamination

Sources of contamination can be summarized in three very

broad categories: agricultural, urban, and industrial.

Agricultural-sourced contamination affects urban

areas in several ways. Use of some pesticides in agricultural

or gardening situations has increased by significant amounts

the levels of

copper

arsenic

, and

mercury

in soils. Long-

term use of

phosphorus

fertilizers can lead to a buildup

of cadmium—a contaminant in many fertilizers—in soils.

Synthetic organic pesticides used in agriculture can also con-

tribute to contamination. Organochlorine insecticides are

persistent and accumulate in food chains. Examples of these

types of compounds are DDT, aldrin, and dieldrin. Use of

these insecticides has been discontinued since their negative

impacts on the

environment

have been well documented.

However, these compounds do not readily decompose and

are very persistent in soils and

sediment

. Former agricultural

areas that have become urbanized have residues of these

chemicals and others that result in a risk for contamination

of water supplies as well as soils. This is especially true for

very localized areas where pesticides were stored, spilled, or

that were regularly used to clean or load spray equipment.

Urban activities past and present also contribute to

contamination. The most common and largest volume of

contamination sources comes from construction or demoli-

tion debris. Much of the debris is made up of nonhazardous

materials; however, some of the debris may contain

asbes-

tos

, high levels of trace metals, or other problem-causing

substances. Asbestos is of particular concern because it can

cause

cancer

in humans when ingested through air or water.

Long-term use of lead-based paints and

gasoline

has

led to considerable contamination. In 1976, the amount of

lead used in gasoline in the United States was approximately

210 million tons (190.5 million metric tons). This has

dropped to less than 50 million tons (45.4 metric tons) per

year since the use of unleaded gasoline has replaced leaded

fuel. Air emissions and deposition of lead from

automobile

exhaust near roads and highways have contaminated numer-

ous urban areas.

Disposal of domestic wastes containing trace metals

and other hazardous materials by land application or in

landfills are also large sources of contamination. Smokestacks

from

incineration

plants for wastes often contain high levels

of trace metals. Polyaromatic

hydrocarbons

(PAHs) have

been deposited in urban areas as the result of

combustion

fossil fuels

(

coal

, peat, etc.) for generating electrical

power. Other urban activities that can lead to contamination

include land application of soot, coal ash, sewage

sludge

and corrosion from metals and buildings.

In addition to agricultural and general urban sources,

industrial activities such as mining and smelting contribute

significantly to localized

soil

metal contamination. Atmo-

spheric transport of the emissions can contaminate sur-

1439

rounding areas. Many industries have contributed a number

of different kinds of toxic materials to the urban environment

and as those industries close or move away they have left

the areas contaminated, making it difficult to use the sites

for other purposes without expensive clean-up. Examples of

toxic materials that are found in former industrial sites in-

clude asbestos, chromium, arsenic, and boron. Asbestos is

found most often in areas that were formerly railroad lands,

shipyards, or asbestos factories. Leather tanning industries

or areas used for battery production leave residues of chro-

mium and arsenic.

Locations near chemical manufacturing companies or

storage and distribution centers are also places where there

is considerable contamination. One of the extreme examples

where such a site was redeveloped after which major prob-

lems arose is

Love Canal

in the state of New York. Up to

248 different industrial chemicals were deposited and buried

at the site before 1953. People living there following redevel-

opment were evacuated after many serious health problems

were reported and confirmed.

Many toxic solvents are used in chemical, paint, and

dye industries, and frequently these solvents can be found

in soils of former industrial sites. In the Silicon Valley of

California, solvent leakages into soils from computer chip

manufacturing have resulted in both soil and

groundwater

contamination. Trichloroethylene and chloroethylene are

common solvents used in paper making, metal plating, elec-

trical engineering, laundries, dry cleaners, and as degreasing

agents. These solvents have caused not only soil contamina-

tion, but also groundwater contamination in numerous loca-

tions. These sites are very difficult and expensive to clean

up after the industries leave.

Contamination by power stations arises from pulver-

ized fuel or

fly ash

, which is alkaline (

10-12) and con-

tains soluble salts, in particular boron,

aluminum

, copper,

and arsenic. The ash results from burning coal and is ex-

tracted from the chimneys to prevent

air pollution

. Its ex-

tremely fine particle size makes it difficult to handle and

dispose. Demolition debris from these sites often contains

asbestos residues, trace metals, combustible materials, oil

spillages, and

polychlorinated biphenyls

(PCBs).

This urban contamination is a major problem world-

wide in industrialized countries. In the Netherlands alone

there have been confirmed at least 10,000 contaminated

sites, with 50% of them in residential areas, with total clean

up costs estimated to be $25 billion. Western Germany has

identified over 50,000 potentially contaminated sites. The

Environmental Protection Agency

(EPA) in the United

States has identified 32,000 potentially

hazardous waste

sites, with an estimated clean-up cost of $750 billion. There

can be large impacts on the growth of plants and on the

health of humans and animals that come in contact with

Environmental Encyclopedia 3

Urban design and planning

the contamination at the site through either the air, water,

or soil. There are three main pathways by which the contami-

nants can enter the plants: direct uptake from soil, vapor

uptake through the air, and

sorption

on plant surfaces. For

organic types of contaminants the predominant pathways

are through the roots or air vapors. In general, organic con-

taminants (including pesticides) can affect plant growth re-

sulting in everything from depressed growth and reproduc-

tion rates to death.

The ability of the plant to take up metals and transmit

them to animals or humans that eat the plants varies by

plant and by metal. Since there are likely to be high concen-

trations of lead either from

petroleum

products or paint in

contaminated sites, there is concern for backyard vegetable

gardens or urban gardens where redevelopment has taken

place. There are similar concerns for other metals such as

zinc and

cadmium

. These metals are usually associated with

electroplating industries or battery production and where

municipal waste sludges have been land applied. High con-

centrations of trace metals can cause visible injury to plants

and inhibit their growth.

The high concentrations of trace metals in many urban

soils in inner-city and highly industrialized areas gives rise to

concerns about potential human health effects. Lead is a trace

metal of particular concern, and two predominant pathways

for the uptake of lead have been identified in humans: soil

and dust ingestion, and consumption of home grown foods.

Depending on the extent of exposure, individuals may develop

symptoms of acute or chronic lead

poisoning

. Symptoms or

results of exposure include severe

anemia

, acute nervousness,

kidney damage, irreversible brain damage, or death. Preschool

children and women of child-bearing age are especially at risk.

It has also been reported that people exposed to lead and cad-

mium in drinking water suffered from increased chronic kid-

ney disease, skin cancer, heart disease, and anemia.

It is estimated that greater than 60% of human cancer

is caused by contacting environmental chemicals containing

PAHs. However, these compounds can be ingested through

contaminated drinking water, but dietary intake of plant-

based food is the largest single route of exposure.

Urban development and various industrial activities

have resulted in extensive contamination in most industrial

countries. When urban redevelopment or expansion is con-

sidered, the potential impacts of this contamination on

plants, animals, and humans needs to be evaluated. Before

the development occurs, contaminated sites need to be

cleaned up, which can be very expensive. Urban populations

that live in or near these sites already may be exposed to a

wide range of contaminants that can have both acute and

chronic health effects. As we push to revitalize our cities,

this is an issue that will become increasingly important.

[James L. Anderson]

1440

ESOURCES

OOKS

Air Pollution, People and Plants. St. Paul, MN: Sagar Krupa, The American

Phytopathological Society, 1977.

Berrow, M. L. “An Overview of Soil Contamination Problems.” In Chemi-

cals in the Environment, edited by J. M. Lester. Lisbon: 1986.

Thornton, I. “Metal Contamination of Soils in Urban Areas.” In Soils in

the Urban Environment, edited by P. Bullock, and P.J. Gregory. Boston:

Blackwell Scientific Publications, 1991.

Urban design and planning

Urban design can be expressed as the three-dimensional

relationship between buildings, open spaces, and streets

within a given area. This visual expression of urban zones

(combined with a specific plan that details where and what

kind of development should occur) can determine the charac-

ter of the community.

Currently, prevalent thinking on the subject of urban

design is that new communities should be compact, mixed

in both housing and commercial development, affordable,

and pedestrian—a move back to living in compact, relatively

self-sufficient communities and neighborhoods. It is a move

back to a traditional community design in which communi-

ties and neighborhoods have affordable housing, jobs, and

retail markets within easy walking distance for its residents.

This concept from the past is being promoted as the

urban design and planning wave of the future. It addresses

some of the ills that were brought about by the rapid subur-

ban expansion after World War II: segregation of housing

from workplace and retail areas, high housing costs, traffic

congestion, long commutes, decay of community life, and

negative environmental consequences (including

air pollu-

tion

and

water pollution

, inefficient use of energy and

materials, etc.).

Proponents suggest that the move back to traditional

urban design is good not only from the standpoint of pro-

moting lost community values, but also positive for the

envi-

ronment

. In fact, they submit that the environmental factors

(such as the desire for clean air) will move the United States

toward adopting this “new” approach. As the country ad-

dresses the issues of environmental quality, problems such

as traffic congestion and affordable housing will become

increasingly important to community design and planning,

and will aid in the continuing

evolution

of urban design.

Urban ecology

Urban

ecology

, simply put, is the study of life in the city.

In the late nineteenth century, biologists and zoologists cre-

ated the field of ecology, seeking to understand the complex

Environmental Encyclopedia 3

Urban ecology

relationships between organisms and their

environment

The term ecosystem started to be used to refer to a community

of organisms and its associated environment when function-

ing as an ecological unit. Since then, the study of ecosystems

has largely been associated with scientific descriptions of

pristine locales, typically in remote regions where human

presence was minimal to non-existent. In contrast, urban

ecology is the study of urban ecosystems. In general, urban

biodiversity

is heavily dominated by alien

species

. There

are exceptions, for instance suburban communities that re-

tain parts of the pre-existing natural

habitat

, but overall,

urban ecosystems are fundamentally

anthropogenic

, mean-

ing that they are man-made.

Evidence of human action on the environment goes

back thousands of years. Human hunters in North America

played a role in the

extinction

of large mammals as far back

as 12,000–5,000 years ago. The development of agricultural

societies led to side effects including

soil erosion

, disease,

and

deforestation

before modern times. In some ancient

cities, ecological degradation was severe, and ruined cities

and cultures have left behind ample evidence for modern day

researchers. Over thousands of years, humanity has played a

major role in changing the ecosystems in which they have

lived, and in modern times this process has become prolific

and widespread.

In the new millenium, ecologists have little doubt that

humanity’s collective will is the dominant force in the welfare

and outcome of the global environment. With nearly half

of the world’s population living in urban areas, and almost

80% of people in developed nations living in cities, mankind

consumes a vast amount of resources, most of which comes

from ecosystems outside the city. Large amounts of renew-

able and non-renewable resources are being transported from

outlying ecosystems into urban ecosystems, while huge quan-

tities of human produced pollutants are being created by

urban ecosystems and spread across the spectrum of ecosys-

tems. For this reason, urban ecologists stress the importance

of understanding, in ecological terms, how the activities of

people affect the total ecological spectrum from pristine

wilderness

to urban areas.

Ecologists define an urban

ecosystem

as a dependent

ecosystem, meaning that it depends on other ecosystems and

outside energy and resources to function. On the other hand,

a natural ecosystem generally has an even balance between

its energetic inputs and outputs. William Rees, a researcher

at the University of British Columbia, created an analytical

tool to measure just how dependent the urban ecosystem is.

Called the “ecological footprint,” it roughly measures how

much land is required to maintain a city’s activities. Rees

found that Vancouver, British Columbia, for instance, had

a footprint 180 times its own size in 1996, meaning that

1441

much more land, in terms of extractable resources, is required

to support its inhabitants.

Another aspect of the urban process being studied is

the urban fringe. The fringe is the expansion point where

human activity, building, and structure meet and alter other

existing ecological or natural settings. Also known as

urban

sprawl

, this process, according to Bioscience magazine,

chewed up an estimated 13 million acres (5.3 million ha) of

land in the United States between 1970 and 1980, and

another 9 million acres (3.6 million ha) in the 1980’s. Addi-

tionally, development of farmland and forest during the

economically booming 1990’s reached a record pace in

America, accelerating to a rate of 3.2 million acres (1.3

million ha) per year by some estimates.

This rapid development has profoundly changed the

ecosystems involved and a thriving branch of urban ecology

studies how patterns of urban development alter the ecologi-

cal composition and organization of species. For example,

the change in predator and prey relationships caused by

human activity has altered the

wildlife

population in several

habitats. Some animals have become more familiar and com-

fortable with the urban environment, and human-to-animal

encounters have increased. Deer have been seen walking

casually through suburban neighborhoods across the United

States, feeding on saplings and freshly planted gardens, and

traffic incidents involving them have increased. In Washing-

ton, D.C. deer have been seen a short distance from the

White House. A

coyote

was found in an elevator in a Seattle

federal building. Many coyote, whose numbers have doubled

since 1850, have been frequently sighted looking for food

in suburbs and urban areas. Another result of human inter-

ference with natural habitats is the changing predation habits

among certain animals. For example, in California, foxes

have begun killing rare bird species. Concern among envi-

ronmentalists and ecologists continues to grow as the phe-

nomenon of urban growth and development increases. Other

fields of study include the mechanisms of

carbon

storage

in the urban forest and cooling of the

atmosphere

by urban

evapotranspiration

Scientists understand that traditional ecological

theory, developed without humans in mind, is not sufficient

for properly understanding urban systems. Instead of consid-

ering humans as being outside or separate from the natural

world, ecologists include humans as a factor affecting the

natural world’s

evolution

. Together with an existent natural

landscape, the forces of human policies and economics have

the greatest impact in how an urban ecosystem is created

and maintained, as well as how plant and wildlife fare. When

looking at cities, ecologists might include data such as species

diversity, population sizes, and

energy flow

. Urban ecolo-

gists would further include qualities having to do with human

perceptions and institutions, including cultural resources,

Environmental Encyclopedia 3

Urban heat island

educational opportunities,

recreation

, wealth, city design

and aesthetics, and community health. Features of the urban

ecosytem include, for instance, money (a property of energy

in the urban ecosystem), downtown high-rises, social institu-

tions, industrial developments, commercial shopping devel-

opments, residential developments of all cultural and eco-

nomic types, open space and recreational parks,

automobile

traffic, pedestrian traffic,

air pollution

and toxic contami-

nants, existing natural landforms, and adaptive plants and

wildlife. The large number of factors influencing the urban

environment shows the need for the inclusion of other sci-

ences in order to understand the urban area’s complexity.

In the United States, the National Science Founda-

tion’s Long-Term Ecological Research (LTER) project has

the goal of creating a full-scale, interdisciplinary urban ecol-

ogy research program that addresses the field’s complex

needs. The project, begun in the 1990’s, is using two sites

for research, in Phoenix, Arizona and Baltimore, Maryland.

Interdisciplinary teams of the project’s scientists are working

to better understand the urban environment. This study

provides an example of how an urban ecology analysis is

conducted. First, researchers focus on the urban

topogra-

phy

, and more precisely analyze a

watershed

(defined as

an area that is being drained, or feeding a body of water) as

a centerpoint. Scientists then begin to link up the ecological

relationships of vegetation and wildlife communities. After

examining the ecological relationships, the next step is to

understand the human socio-cultural characteristics of the

watershed. Different areas along watersheds have different

land values. Urban ecologists study the relationship between

the natural features of the watershed and how humans inter-

act, according to different sociological characteristics such

as age, gender, ethnic identity, and social status. Significant

patterns can often be seen between social factors and a partic-

ular urban area’s biophysical (natural) characteristics. For

instance, studies have found that wealthy city dwellers tend

to live in areas that are environmentally healthier and less

polluted than those lived in by poorer city dwellers. The

LTER project is comprehensively addressing issues like this,

using a variety of scientific methods.

The science of urban ecology is also part of a growing

awareness that the health of the overall environment depends

upon the health of cities. In addition to the scientific study

of ecology, this awareness is also associated with the more

activist areas of “ecological urbanism” and “new urbanism,”

as well as “green living” and “sustainable development” trends

in urban planning. The aims of ecological urbanism and

new urbanism are to create justice and equity in social and

environmental policy

. These movements also strive to re-

form urban landscapes and urban planning methods to create

sustainable, healthy cities by reducing pollutants and waste,

while increasing

conservation

and the accessibility of shared

1442

resources, to insure humanity’s survival and quality of life.

Urban ecology contributes the resources of knowledge and

information to these social movements, and to those who

seek a deeper understanding of the relationship between

humanity and the natural world, helping them see their city

as part of a living ecosystem with valuable resources that

promote better health and quality of life.

[Douglas Dupler]

ESOURCES

OOKS

Beatley, Timothy, and Kristy Manning. The Ecology of Place: Planning for

Environment, Economy, and Community. Washington, DC: Island Press,

1997.

Breuste, Jurgen, Hildegard Feldman, and Ogarit Uhlman. Urban Ecology.

Berlin, New York: Springer-Verlag, 1998.

Bridgman, Howard A., Robin Warner, and John Dodson. Urban Biophysical

Environments. New York: Oxford University Press, 1995.

Matthews, Anne. Wild Nights: Nature Returns to the City. New York: North

Point Press, 2001.

Rocky Mountain Institute. Green Development: Integrating Ecology and Real

Estate. New York: John Wiley & Sons, 1998.

THER

The Baltimore Ecosystem Project. [cited July 2002]. <http://www.ecostudie-

s.org/bes>.

RGANIZATIONS

The Center for Urban Ecology, 4598 MacArthur Blvd., NW., Washington,

DC USA 20007-4227 202-342-1443, Fax: 202-282-1031, <http://

www.nps.gov/cue/cueintro.html>

Urban Ecology, 414 13th Street, Suite 500, Oakland, CA 94612 510-

251-6330, Fax: 510-251-2117, Email: urbanecology@urbanecology.org,

<http://www.urbanecology.org/>

Urban heat island

An urban area where the temperature is commonly 5–10°F

(−15–−12°C) warmer than the surrounding countryside. Ef-

fects include reduced heating but higher air conditioning

bills. Within cities, this warmth causes spring to arrive one

to two weeks earlier and fall foliage to appear one to two

weeks later. The chief cause is the high energy use within

cities, which ultimately ends up in the

atmosphere

as waste

heat. Also important, however, are the darker surfaces within

cities, which absorb more heat, the relative absence of vegeta-

tive cooling through

transpiration

because of fewer trees,

and less wind because of building obstructions.

Urban runoff

Urbanization causes fundamental changes in the local

hy-

drologic cycle

, mainly increased speed of water movement

through the system, and degraded

water quality

. They are

Environmental Encyclopedia 3

Urban runoff

expressed through reduced

groundwater

recharge, faster

and higher

storm runoff

, and factors that affect aquatic

ecosystems, particularly

sediment

dissolved solids

, and

temperature. The resultant problems have encouraged mu-

nicipalities to reduce negative impacts through storm water

management.

Important research on these issues was spearheaded

by the U.S.

Geological Survey

(USGS) during the early

phases of the current environmental revolution. A sampling

of titles used for the USGS Circular 601 series indicates the

scope of these efforts: Urban Sprawl and Flooding in Southern

California (C601-B); Flood Hazard Mapping in Metropolitan

Chicago (C601-C); Water as an Urban Resource and Nuisance

(C601-D); Sediment Problems in Urban Areas (C601-E); and

Extent and Development of Urban Flood Plains (C601-J).

Also relevant are Washington D.C.’s Vanishing Springs and

Waterways (C752), and Urbanization and Its Effects on the

Temperature of the Streams on Long Island, New York (USGS

Professional Paper 627-D).

Most of these works cite a 1968 publication written

by Luna Leopold, Hydrology for Urban Land Planning. De-

scribing a research frontier, Leopold anticipated many of

the concerns currently embodied in stormwater management

efforts. He identified four separate but interrelated effects

land use

changes associated with urban

runoff

:1)

changes in peak flow characteristics, 2) changes in total

runoff, 3) changes in water quality, and 4) aesthetic or ame-

nities issues.

Urbanization transforms the physical

environment

a number of ways that affect runoff. Initially construction

strips off the vegetation cover, which results in significantly

increased

erosion

. Local comparisons with farms and wood-

lands show that sediment from construction and highway

sites may increase 20,000–40,000 times. Furthermore, as

slope angles steepen, the erosion rate increases even faster;

and above a 10% slope (10 ft [3 m] rise in 100 ft [30 m])

no restraints remain to hold back this sediment. On a larger

scale, a Maryland study comparing relatively unurbanized

and urbanized basins found a fourfold erosion increase.

Pavement and rooftops cover many

permeable

areas

so that runoff occurs at a greater rate. Storm sewers are built

which by their very nature speed up runoff. Estimates range

from a two- to six-fold increase in runoff amounts from

fully urbanized areas. Even more important, however, is that

peak

discharge

(the key element in

flooding

) is higher and

comes more quickly. This makes flash floods more likely,

and increases the frequency of runoff events that exceed

bank capacity.

This increased flooding causes much channel erosion

and altered geometry, as the channels struggle to reach a

new equilibrium. Less water infiltrates into groundwater

reservoirs, which diminishes the base flow (the

seepage

1443

groundwater into humid-region channels) and causes springs

to dry up. The

urban heat island

effect, combined with

reduced baseflow, exposes aquatic ecosystems to higher heat

stress and reduced flow in summer, and to colder tempera-

tures in winter. Summer is especially difficult, as rainwater

flows from hot streets into channels exposed to direct sun-

light. As a consequence, sustaining life becomes more diffi-

cult, and sensitive organisms must adapt or die.

Water quality changes increase

cultural eutrophica-

tion

(

water pollution

caused by excessive plant nutrients),

fertilizer

and

pesticide

residues wash from lawns and

gardens to join the oil,

rubber

, pet manure, brake lining

dust, and other degrading elements comprising urban

drain-

age

. When these are combined with the

effluent

from

industrial waste and treated sewage, especially

heavy met-

als

, the riverine environment becomes a health concern.

Under

arid

conditions, the damage from mudflows

may be increased because the land that once absorbed the

sliding mud is now covered with streets and buildings. This

situation can be seen in southern California, where hillside

development has increased the threat of landslides.

Increasing attention is now being given to stormwater

management around the United States. For example, Seattle,

Washington has focused on water quality, whereas Tulsa,

Oklahoma is primarily concerned with flooding. Both cities

have responded to serious local problems.

By the 1950s, Seattle’s

Lake Washington

and the

adjacent water of Puget Sound had become so polluted that

beaches had to be closed.

Sewage treatment

plants around

Lake Washington and raw sewage dumping in Puget Sound

were the fundamental causes. The residents of the area voted

to form a regional water-quality authority to deal with the

problems. As a result, all sewage treatment was removed

from Lake Washington, and dumping of raw sewage into

Puget Sound was halted. The environmental result was dra-

matic. As nitrate and phosphate levels dropped sharply, cul-

tural eutrophication in these waters was greatly reduced, and

beaches were reopened. The regional agency continues to

seek better ways to improve the water quality of stormwater

runoff.

Tulsa’s efforts are a response to a series of devastating

floods. Between 1970 and 1985, Tulsa led the country in

numbers of federal flood declarations; these floods caused

17 deaths and $300 million in damages. Conditions in Tulsa

are such that 6.3 in (16 cm) of rain within six hours is

sufficient to produce what hydrologists call a 100-year flood.

In May 1984, 10 in (25 cm) of rain fell during a seven-hour

period, which was a rainfall frequency of about 200 years.

A leader in flood control, Tulsa has taken a multi-

faceted approach to stormwater management. During the

1970s, then Congressman James R. Jones sponsored legisla-

tion to buy out and tear down houses in the severely flood-

Environmental Encyclopedia 3

Urban sprawl

prone Mingo Creek Basin; some had qualified seven times

for flood disaster aid, with payments far exceeding market

value. In a joint venture, Tulsa and the

Army Corps of

Engineers

have spent $60 million and $100 million respec-

tively to channelize Mingo Creek in its lower reaches and

create detention ponds in the middle portions of the basin.

Expected benefits include a $26.9 million reduction in an-

nual flood damage. Continuing flood control efforts have

incorporated the use of a state-of-the-art computerized flood

warning system.

Recreational possibilities are being exploited in Tulsa’s

overall stormwater management program. Access roads are

being used as running tracks; athletic fields double as deten-

tion reservoirs during flood conditions. Since existing parks

have been modified to meet the flood program needs, the

facilities have benefitted from the improvements, and the

water authority leaves the maintenance to the parks depart-

ment. Using existing parks also eliminates the need to buy

out houses and disrupt existing neighborhoods.

Although the Tulsa plan has been successful, more

heavily developed floodplains require different measures. Of-

ten land costs are so high that it may be cheaper to spend

money on flood-proofing or tearing down existing buildings.

In any event, urban runoff is an expensive problem to solve.

See also Heavy metals and heavy metal poisoning; Industrial

waste treatment; Land-use control; Water treatment

[Nathan H. Meleen]

ESOURCES

OOKS

Howard, A. D., and I. Remson. Geology in Environmental Planning. New

York: McGraw-Hill, 1978.

Mrowka, J. P. “Man’s Impact on Stream Regimen and Quality.” In Perspec-

tives on Environment, edited by I. R. Manners and M. W. Mikesell. Wash-

ington, DC: Association of American Geographers, 1974.

THER

Leopold, L. B. Hydrology for Urban Land Planning: A Guidebook on the

Hydrologic Effects of Urban Land Use. USGS Circular 554. Washington,

DC: U.S. Government Printing Office, 1968.

Urban sprawl

Today, most American cities are characterized by decaying

central downtowns from which residents and businesses have

fled to low-density suburbs spreading out around a network

of increasingly congested freeways. This development pat-

tern consumes open space, wastes resources, and leaves his-

toric central cities with a reduced tax base and fewer civic

leaders living or working in downtown neighborhoods.

Streets, parks, schools, and civic buildings fall into disrepair

at the same time that these facilities are being duplicated at

1444

great expense in new suburbs. The poor who are left behind

when the upper and middle classes abandon the city center

often can’t find jobs where they live and have no way to

commute to the suburbs where jobs are now located. The

low-density development of suburbs is racially and economi-

cally exclusionary because it provides no affordable housing

and makes it impractical to design a viable public transit

system.

At the same time that inner cities are hollowing out,

the amenities that people have moved to the outskirts in

search of prove to be fleeting. Hoping to find a open space,

opportunities for outdoor

recreation

, access to wild

nature

scenic views, and a rural ambience, they find, instead, sprawl-

ing developments based on only a few housing styles. The

checkerboard layout of nearly identical lots with little public

space is permitted—or even required—by local zoning and

ordinances, consumes agricultural land and fragments

wild-

life habitat

. To make house construction more efficient,

land in large housing developments generally is bulldozed,

removing vegetation or other landmarks that might make a

neighborhood recognizable.

Traffic becomes increasingly congested as more and

more cars clog streets and freeways, driving the much longer

distances to jobs and shopping required by dispersed living

patterns. In Los Angeles, for example, which has the worst

congestion in the United States, the average speed in 1982

was 58 mph (93 km/hr) and the average driver spent less

than four hours per year in traffic jams. In 2000, the average

speed in Los Angeles was only 35.6 mph (57.3 km/hr) and

the average driver spent 82 hours per year waiting for traffic.

Although new automobiles are much more efficient and

cleaner operating than those of a few decades ago, the fact

that we drive so much further today and spend so much

more time idling in stalled traffic means that we burn more

fuel and produce more

pollution

than ever before. Thus,

the poor urban

air quality

people fled to the country to

escape follows them and is made worse by the greater dis-

tances they drive every day.

Altogether, traffic congestion is estimated to cost the

United States $78 billion per year in wasted time and fuel.

Some people argue that the existence of traffic jams in cities

shows that more freeways are needed. Often, however, build-

ing more traffic lanes simply encourages more people to drive

further than they did before. Rather than ease congestion and

save fuel, more freeways can exacerbate the problem.

As Maryland Governor Parris N. Glendening said:

“In its path, sprawl consumes thousands of acres of forests

and farmland, woodlands and

wetlands

. It requires govern-

ment to spend millions extra to build new schools, streets

and water and sewer lines.” Christine Todd Whitman, for-

mer New Jersey Governor and Head of the

Environmental

Protection Agency

(EPA), has said, “Sprawl eats up our

Environmental Encyclopedia 3

Urban sprawl

open space. It creates traffic jams that boggle the mind

and pollute the air. Sprawl can make one feel downright

claustrophobic about our future.” While there is no univer-

sally accepted definition of urban sprawl, it generally includes

the characteristics:

unlimited outward urban expansion

low-density residential and commercial development

leapfrog growth that consumes farmland and natural areas

fragmentation of power among many small units of gov-

ernment

dominance of freeways and private automobiles

no centralized planning or control of land-uses

widespread strip-malls and “big-box” shopping centers

great fiscal disparities among localities

reliance on deteriorating older neighborhoods for low-in-

come housing

decaying city centers as new developments occurs in pre-

viously rural areas

Among the alternatives to unplanned sprawl and

wasteful resource use proposed by urban planners are

smart

growth

and

conservation

design. These new approaches

make efficient and effective use of land resources and existing

infrastructure by encouraging development that avoids costly

duplication of services and inefficient

land use

. They aim

to provide a mix of land uses to create a variety of affordable

housing choices and opportunities. They also attempt to

provide a variety of

transportation

choices including pedes-

trian friendly neighborhoods. This approach to planning

also seeks to maintain a unique

sense of place

by respecting

local cultural and natural features.

By making land use planning open and democratic,

smart growth and conservation design strive to make urban

expansion fair, predictable, and cost-effective. All stakehold-

ers are encouraged to participate in creating a vision for the

city and to collaborate rather than confront each other. Goals

are established for staged and managed growth in urban

transition areas with compact development patterns. This

approach is not opposed to growth. It recognizes that the

goal is not to block growth but to channel it to areas where

it can be sustained over the long term. It tries to enhance

access to equitable public and private resources for everyone

and to promote the safety, livability, and revitalization of

existing urban and rural communities.

Rather than abandon the cultural history and infra-

structure investment in existing cities a group of architects

and urban planners is attempting to redesign metropolitan

areas to make them more appealing, efficient, and livable.

European cities such as Stockholm, Sweden, Helsinki, Fin-

land, Leichester, England, and Neerlands, the Netherlands,

have a long history of innovative urban planning. In the

United States, Andres Duany, Elizabeth Plater-Zyberk, Pe-

1445

ter Calthorpe, and Sym Van Der Ryn have been leaders in

what is sometimes called the new urbanist movement or neo-

traditionalist approach. These designers attempt to recapture

some of the best features of small towns and the best cities

of the past. They are designing urban neighborhoods that

integrate houses, offices, shops, and civic buildings. Ideally,

no house should be more than a five-minute walk from a

neighborhood center with a convenience store, a coffee shop,

a bus stop, and other amenities. A mix of apartments, town-

houses, and detached houses in a variety of price ranges

insures that neighborhoods will include a diversity of ages

and income levels.

Where building new neighborhoods in rural areas is

necessary, conservation design, cluster housing, or open

space-zoning preserves at least half of a subdivision as natural

areas, farmland, or other forms of open space. Among the

leaders in this design movement are landscape architects Ian

McHarg, Frederick Steiner, and Randall Arendt. They have

shown that people who move to the country don’t necessarily

want to own a vast acreage or to live miles from the nearest

neighbor; what they most desire is long views across an inter-

esting landscape, an opportunity to see wildlife, and access to

walking paths through woods or across wildflower meadows.

By carefully clustering houses on smaller lots, a conser-

vation subdivision can provide the same number of buildable

lots as a conventional subdivision and still preserve 50–70%

of the land as open space. This not only reduces development

costs (less distance to build roads, lay telephone lines, sewers,

power cables, etc.) but also helps foster a greater sense of

community among new residents. Walking paths and recre-

ation areas get people out of their houses to meet their

neighbors. Homeowners have smaller lots to care for and yet

everyone has an attractive vista and a feeling of spaciousness.

Some good examples of this approach are Farmview

near Yardley, Pennsylvania, and Hawknest in Delafield

Township, Wisconsin. In Farmview, 332 homes are clustered

in six small villages set in a 414 acre (160 ha) rural landscape,

more than half of which is dedicated as permanent farmland.

House lots and villages were strategically placed to maximize

views, helping the development to lead its county in sales for

upscale developments.Hawksnest is situated in dairy-farming

country outside of Waukesha, Wisconsin. Seventy homes are

situatedamid 180 acres(70 ha) ofmeadows, ponds, andwood-

lands. Restored

prairie

, neighborhood recreational facilities,

and connections to a national scenic trail have proved to be

valuable marketing assets for this subdivision.

[William P. Cunningham Ph.D.]

ESOURCES

OOKS

Arendt, Randall G. Conservation Design for Subdivisions: A Practical Guide

to Creating Open Space Networks. Covelo, CA: Island Press, 1996.

Environmental Encyclopedia 3

U.S. Department of Agriculture

Beatly, T. Green Urbanism: Learning from European Cities. Covelo, CA:

Island Press, 2000.

Benfield, F. Kaid, Donald D. T. Chen, and Matthew D. Raimi, eds.

Once There Were Greenfields: How Urban Sprawl Is Undermining Americas’s

Environment, Economy, and Social Fabric. New York: Natural Resources

Defense Council, 1999.

Calthorpe, Pete, and William Fulton. The Regional City: Planning for the

end of Sprawl. Covelo, CA: Island Press, 2000.

Duany, Andres, Jeff Speck, and Elizabeth Plater-Zyberk. Smart Growth

Manual. New York: McGraw-Hill Co., 2002.

McHarg, Ian. Design with Nature. New York: John Wiley & Sons, 1995.

Ursus arctos

see

Grizzly bear

U.S. Department of Agriculture

The U.S. Department of Agriculture (USDA) had its origin

in the U.S. Patent Office, one of the first federal offices. In

1837, an employee of the Patent Office, Henry L. Ellsworth,

began to distribute seeds to American farmers that he had

received from overseas. By 1840, Ellsworth had obtained a

grant of $1,000 from Congress to establish an Agricultural

Division within the Patent Office. This division was charged

with collecting

statistics

on agriculture in the United States

and carrying out research, as well as distributing seeds.

Over the next two decades, the Agricultural Division

continued to expand within the Patent Office, until Congress

created the Department of Agriculture on May 15, 1862.

The officer in charge of the department was initially called

the Commissioner of Agriculture, but the Department was

raised to cabinet level on February 9, 1889, and the Commis-

sioner was renamed the Secretary of Agriculture.

The USDA today is a mammoth executive agency that

manages dozens of programs. Its overall goals include the

improvement and maintenance of farm incomes and the

development of overseas markets for domestic agricultural

products. The department is also committed to reducing

poverty, hunger, and malnutrition; protecting

soil

, water,

forests, and other

natural resources

; and maintaining stan-

dards of quality for agricultural products. The activities of

the USDA are subdivided into seven major categories: Small

Community and Rural Development, Marketing and In-

spection Services, Food and Consumer Services, Interna-

tional Affairs and Commodity Programs, Science and Edu-

cation, Natural Resources and

Environment

, and

Economics.

Small Community and Rural Development oversees

many of the programs which provide financial assistance to

rural citizens. It administers emergency loans as well as loans

for youth projects, farm ownership, rural housing,

water-

shed

protection, and flood prevention. It also underwrites

1446

federal crop insurance, and the Rural Electrification Admin-

istration is part of this division.

Marketing and Inspection Services is responsible for

all activities relating to the inspection and maintenance of

health standards for all foods produced in the United States.

The Agricultural Cooperative Service, which many consider

one of the USDA’s most important functions, is part of

the division. Food and Consumer Services helps educate

consumers about good nutritional practices and provides the

means by which people can act on that information. The

division administers the Food Stamp program, as well as

the School Breakfast, Summer Food Service, Child Care

Food, and Human Nutrition Information programs.

The main functions of the International Affairs and

Commodity Programs are to promote the sale and distribu-

tion of American farm products abroad and to maintain crop

yields and farm income at home. The Science and Education

division consists of a number of research and educational

agencies including the

Agricultural Research Service

, the

Extension Service, and the National Agricultural Library.

Some of the USDA’s best known services are located

within the Natural Resources and Environment Division.

The

Forest Service

and

Soil Conservation Service

are the

two largest of these. The Economics Division is responsible

for collecting, collating, and distributing statistical and other

economic data on national agriculture. The Economic Re-

search Service, National Agricultural Statistics Service, Of-

fice of Energy, and World Agricultural Outlook Board are

all part of this division.

[Lawrence H. Smith]

ESOURCES

OOKS

The United States Government Manual, 1992/93. Washington, DC: U.S.

Government Printing Office, 1992.

RGANIZATIONS

U.S. Department of Agriculture, Washington, D.C. USA 20250 Email:

vic.powell@usda.gov, <http://www.usda.gov>

U.S. Department of Commerce

see

National Oceanic and Atmospheric

Administration (NOAA)

U.S. Department of Defense

see

Army Corps of Engineers