Environmental Sci Chap 1

Environmental Science
Chapter 1 Notes
D.Knauss
RRHS
2006
• study how humans interact with environment
(study how humans interact w/env.)
- major goal is to understand and solve environmental
problems
(GOAL- understand + solve env. Problems)
- study 2 main types of interactions between humans
and their environment
• how we use natural resources
• how our actions alter the environment
- an interdisciplinary science
– one important foundation of environmental
science is ecology
Ecology
• study of how living things interact with
each other and their nonliving environment
- major fields of study that contribute to
environmental science:
- biology
- earth science
- physics
- chemistry
- social science
Ecology
• often the observations of nonscientists are
the first step toward addressing an
environmental problem
Hunter-gatherers
• people who obtain food by collecting plants
and by hunting wild animals or scavenging
their remains
- groups were small and migrated during
different times of the year based on food supply
- hunted bison
- set fires to burn prairies and prevent tree
growth
– helped spread plants
Hunter-gatherers
– rapid climate change and overhunting led to
extinctions of giant sloths , mastodons, cave
bears, and saber-toothed cats
Agriculture
• practice of growing, breeding, and caring
for plants and animals that are used for
food, clothing, housing, transportation, and
other purposes.
– started over 10,000 years ago and changed
society and the environment so much that it is
called the agricultural revolution
Agriculture
- humans populations grow at an incredible rate
- an area of land can support up to 500x as many
people by farming than by hunting and
gathering
- populations concentrated into smaller areas,
placed increased pressure on local
environments
– changed food we eat by creating domesticated
plants
Agriculture
- habitat destroyed using slash and burn
agriculture
– forest replaced by farmland causes soil loss,
floods, and water shortages
Industrial Revolution-
• involved a shift from water-, animal-, and
human-powered energy sources to fossil
fuels
– increased efficiency of agriculture, industry,
and transportation
– large-scale production of goods in factories
became less expensive than local production
– on the farm, machinery reduced the amount of
land and labor needed to produce food.
- Populations in urban areas grew as people
stopped growing their own food
- Motorized vehicles allowed food and goods
to be transported cheaply across long
distances
- Improved the quality of life….light bulb
- Agricultural productivity increased,
sanitation, nutrition and medical care
improved
- Pollution and habitat loss became more
common
- Artificial substances began to be used
which bring about their own sets of
problems
Closed system
• only the energy from the sun enters and the
only thing that leaves is heat
- potential problems involve some resources that
are limited and the fact that we will produce
more wastes than we can dispose of them.
- environmental problems can occur on different
scales: local, regional, or global
Closed system
- population growth increases, caused by
industrial and agricultural revolutions along
with modern medicine and sanitation
- human population almost quadrupled during the
20th century
– producing enough food has environmental
consequences—habitat destruction and
pesticide pollution
Closed system
- most scientists believe the population will
double before it begins to stabilize in the
21st century
Main Environmental Problems
Resource Depletion
• Natural Resource- any natural material that
is used by humans- 2 types
– Renewable- can be replaced relatively quickly
by a natural process
– Nonrenewable- forms at a much slower rate
than the rate at which it is consumed
Resource Depletion
• most common are minerals and fossil
fuels….could take millions of years to
replenish it
• depleted- a large fraction has been used up
Pollution
- a change in air, water, or soil that adversely
affects the health, survival, or activities of
humans or other organisms. Two main
types:
– biodegradable pollutants- pollutants that can be
broken down by natural processes
– nondegradable pollutants- pollutants that cannot
be broken down by natural processes
Loss of Biodiversity
- Biodiversity- refers to the number and
variety of species that live in an area
- Mass extinction- large-scale extinction
- Permian period, 95% of all species became
extinct
- Organisms that share the world with us can
be considered natural resources
Loss of Biodiversity
- Important to preserve organisms due to their
potential economic, ecological, scientific,
aesthetic, and recreational value.
“The Tragedy of the Commons”
- Garrett Hardin, 1968, published an essay

arguing that the main difficulty in solving
environmental problems is the conflict
between the short-term interests of
individuals and the long term interests of
society.
• Commons- areas of land that belonged to a
whole village where anyone could graze
cows or sheep.
- If too many animals grazed the commons

then the animals destroyed the grass and
everyone would suffer.
- So everyone in the group had to take
responsibility for maintaining the resource.
- Hardin did not consider the social nature of

humans. Humans live in groups and depend
on one another.
- Solution may override the interests of
individuals in the short term but improves
the environment for everyone in the long
term
Economics and the Environment
1) Law of Supply and Demand-
• the greater the demand for a limited supply

of something, the more that thing is worth.
• price of oil is an example
2) Costs and Benefits-
- Cost-Benefit Analysis- balances the cost of

the action against the benefits one expects
from it
- The results depend on who is doing the analysis
- Industry- cost of pollution control outweighs
the benefits
• Community- benefits outweigh the high
price
3) Risk Assessment-
• tool that helps us create cost-effective ways
to protect our health and the environment
• public must perceive the risk accurately in
order to come up with an effective solution
to an environmental problem.
Developed and Developing
Countries
Undeveloped Countries-
• lower average incomes, simple and
agriculture-based economies, and rapid
population growth.
• In-between the two types are middle-
income countries (Mexico, Brazil, and
Malaysia)
Population and Consumption
- almost all population problems can be
traced back to two root causes
- 1) human population is growing too quickly
for the local environment to support
- 2) people are using up, wasting, or polluting
many natural resources faster than they can
be renewed, replaced, or cleaned up
Local Population Pressures
- in severely overpopulated regions
- forests are stripped, topsoil is exhausted,
animals are driven to extinction
- constant threats of malnutrition, starvation, and
disease
- population grows most rapidly in these areas
- food production, job creation, and education
cannot keep pace
Local Population Pressures
– of the 4.5 billion people in developing
countries, fewer than half have safe drinking
water, enough food, and proper sanitation
Consumption Trends
- in wealthy countries
- improved pollution controls, population has
stabilized or is growing slowly
- use much more of the earth’s resources
- developed nations use about 75% of world’s
resources and make up 20% of population
- more waste and pollution produced per person
Ecological Footprint-
• productive area of the Earth needed to
support one person in a particular country
- includes land use(crops, grazing, forest
products, and housing), ocean area(seafood),
and forest area (absorb air pollution)
• U.S.- requires 30 acres of land per person
Environmental Science in
Context
• how do you balance the rights of individuals
and property owners with the needs of
society as a whole?
Critical Thinking and the
Environment
• people need to make informed decisions
and be aware that information can be
distorted to suit whoever is using it
• First- be prepared to listen to many
viewpoints
• Second- investigate the source of the
information you encounter and question the
conclusions that are drawn from the data.
A Sustainable World
• Sustainability- the condition in which
human needs are met in such a way that a
human population can survive indefinitely
• not an unchanging world
• requires everyone’s participation

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Environmental Science

- Garrett Hardin, 1968, published an essay

- If too many animals grazed the commons

- Hardin did not consider the social nature of

• the greater the demand for a limited supply

- Cost-Benefit Analysis- balances the cost of

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