Transcript Introduction to Environmental Science

Introduction to Environmental
Science
Ch 1 Science & Environment
• Section 1 Understanding our environment
– I can define environmental science.
– I can compare and contrast environmental
science and ecology
– I can list the 5 major fields of study that
contribute to environmental science
– I can describe the major effects of humans on
the environment throughout history
Section 1
– I can distinguish between renewable and
non-renewable resources
– I can classify environmental problems into
three major categories
Introduction to Environmnetal
Science
How do you define “environment”?
Introduction to Environmental
Science
• Environment –
– Everything around us, living and nonliving,
natural and man-made
– Includes the relationships between these
components of the environment
What is Environmental Science?
Definition of environmental science:
the interdisciplinary study of
(1) how the earth works,
(2) how we interact with the earth, and
(3) how to deal with environmental
problems
Let’s break that down…
Definition of Environmental Science
EnvironmentalSciene
is a broad,
interdisciplinary ,
applied science
ES includes many
fields of study,
including Biology,
Earth science,
Chemistry, Physics,
Social Sciences
Definition of Environmental Science
(1) how the earth works
How do the four spheres of our planet function
naturally to maintain a balance?
• atmosphere
• biosphere
• lithosphere
• hydrosphere
Definition of Environmental Science
(2) how we interact with the earth (our
impact on the environment)
How do we upset the natural balance?
How do we use resources?
How do we produce waste?
What do we do with out waste?
Definition of Environmental Science
(3) how to deal with environmental
problems
To reduce or eliminate our unbalancing
effect:
Decision making
Problem solving
Why study Environmental Science?
Rapid changes in earth’s environment
due to human activities can be traced
to two “revolutions”:
• Life has existed on earth for 3.8 billion
years
• Earth well suited for life
– Water covers ¾ of planet
– Habitable temperature
– Moderate sunlight
– Atmosphere provides oxygen and carbon
dioxide
– Soil provides essential minerals for plants
• But humans are altering the planet; not
always in positive ways
POPULATION
• Globally, 1 in 4 people lives
in extreme poverty
– Cannot meet basic need for
food, clothing, shelter, health
• Difficult to meet population
needs without exploiting
earth’s resources
OVERPOPULATION
• People overpopulation
– Too many people in a given geographic area
– Problem in many developing nations
• Consumption overpopulation
– Each individual in a population consumes too
large a share of the resources
– Problem in many highly developed nations
Hunter-Gatherers
Humans and our ancestors
Hunter-Gatherers
• 60,000-12,000 years ago
• Nomadic – followed plants & animals
(allowed nature to repair itself)
• Lived in small groups-impact low
• Life expectancy – 30-40 years
• Experts on native plants
• Low resourse use per person
• Over-hunting: disappearance of species?
Hunter-Gatherers
Discovery of Fire
• Effect on vegetation widespread &
devastating (kept grasslands open)
• Affected areas where original action not
intended (not all environments adapted to
withstanding fire)
• Can be repetitive and cover the same area
at frequent intervals
• Selective in its effect on species
Domestication of plants
Agricultural Revolution
Gradual move from nomadic lifestyle of
hunter-gatherers to the farming of
domesticated animals and plants
Started about 10,000 years ago
Led to human population
explosion
Can you explain why???
Agricultural Revolution
• 12,000-10,000 years ago (end of last ice
age)
• Domestication of:
– Plants by women (artificial selection of best
grains) (figs, rice, barley, wheat)
– Animals (wolves 3000BC, goats & sheep,
horses)
Longer life span (better food)
• Deliberate destruction of natural
vegetation to cultivate elected crops
• Forced people to settle in specific places
• Caused development of towns – led to
changes in land use and population
growth (500xs as many people as hunting)
• Created problems for waste disposal
• People began to accumulate material
good
• Development of harmful chemicals &
pesticides
• Survival of native plants & animals, once
vital to survival, became less important
• Growth of more food, enabling populations
to expand
• Conflict between society more common as
ownership of land & water rights became
crucial economic issues
• Encouraged use of domesticated animals
in work (ploughing, transport)
• Large forested areas cleared for farms
• Created soil erosion, orgrazing, and other
environmental problems (collapse of
civilization in Tigris-Euphrates river basin
through salt contamination in overworked
soil)
slash & burn
Archaeological record indicates that plant & animal
domestication arose independently in at least 7,
and possibly more, separate locales
Centers of domestication
b.p.)
Near East/"fertile crescent“
Northern China
Southern China (?)
Central Mexico
Peruvian Andes
Papua New Guinea
West Africa
Eastern No. America
Dates (years
11,000
9,000
8,000
5,750
5,250
6-9,000
4,500
4,000
Urbanization
• Large-scale disruption of forests
• Improvements in human welfare &
expansion of human populations beyond
limits set by pre-agriculture patterns of life
• Growth in transportation and polllution
problems
European Colonization
• Large scale environmental degradation
under colonial exploitation of resources in
former colonies in Africa, Latin America,
India
• No regard for environmental
consequences
• Devalued natural resources in colonial
states
PROBLEMS
• 1. Dependency on few plants--Agriculture
made human communities dependent on
relatively few plants--the main crops which
they grew--rather than on the many
different kinds of plants which huntergatherers use.
• 2. Greater vulnerability to weather—
•Complete dependency on harvest times--To
survive, agriculturalists have to gather all their
food for the year at one or two or three harvest
times, rather than gathering year round.
•Nothing can be allowed to interrupt the harvest.
• Agricultural communities became more timeconscious.
•store the produce of their fields for the rest
of the year, protect it from moisture, vermin,
and thieves
•learn to dole out supplies in measured
quantities so the community can survive
• have seed for next year's planting.
•
•These conditions created a new kind of life
style.
4. Need for intense physical labor
specialization becomes possible
5. wealth acquires meaning
6.Humans had never before lived in large
groups or in densely packed spaces. They
had to learn how to do so successfully
(perhaps we are still learning how).
• problem of polluting one's living space
• need to develop elaborate cultural means of
disposing of their dead, or of their food wastes
or excrement, or of the wastes of their livestock.
• Mobile hunter-gatherer groups must necessarily
limit the number of children they have to care for
at any given time; large families of many
children mean more hands to help in the fields.
• infectious disease, a problem closely related to
population growth and to the difficulty of
maintaining a clean, healthy living space.
Industrial Revolution
Industrial Revolution
Development of machines to do manual/animal
labor
Led to use of non-renewable energy sources
(fossil fuels) that disrupt the balance of our
ecosystems (started in mid-1700’s – recent!)
Industrial Revolution
• Large scale use of fossil fuels & mineral
resources that pollute air, soil &
environment
• Development of new forms of
transportation - boosted international trade
and made available goods & services in
distant locations
• Created shift from dependence on
renewable fuels to dependence on nonrenewable fuels
•
•
•
•
•
•
Began in England in mid 1700’s
Spread to US in 1800’s
People lived longer & healthier
Environmental degradation increased
Factory towns sprang up, people left farms
Factory towns grew polluted, noisy,
hazardous
• Coal smoke filled cities
• Reduced amount of land & labor needed
for farming
• Improved quality of life: electricity,
sanitation, nutrition, medical care
improved, improved communication
through telephone & computer
• Shift from natural products & medicines to
man-made (plastics, synthetics)
The Human Population Over Time:
Locate agricultural and industrial revolutions….
Yr. each billion was
reached
2015*
1999
1987
1974
1960
1930
1880
* projected
Scale of Environmental
Problems
Environmental problems are
typically categorized by the
affected population.
•Global problems, like global
warming and the hole in the
ozone layer affect the entire
world population.
•Local problems, such as
deforestation or pollution, can
occur on a local scale
“Spaceship Earth”
Earth - a closed system,
meaning materials do
not enter or leave
Limit to resources
Damage that occurs
stays in the system
Energy enters from sun,
heat leaves
10 Major Problems Facing Earth’s Environment
(from Collapse by Jared Diamond)
1. Destruction of
natural habitat
2. Loss of biodiversity
3. Soil damage and
erosion
4. Use of fossil fuels as
our main energy
source
5. Overuse of
freshwater resources
10 Major Problems Facing Earth’s
Environment
6. Release of toxic materials
7. Introduction of “alien” species
8. Release of harmful gases into
atmosphere
9. Human population growth
10. Increasing standard of living
A tragic metaphor for “Spaceship
Earth” ?
Easter Island is a relatively small, isolated Pacific island on
which there are hundreds of large stone sculptures,
indicating that a complex society once lived there
Reference on Easter Island, Collapse: How Societies Choose to Fail or
Succeed, by Jared Diamond
A tragic metaphor for “Spaceship
Earth” ?
When European explorers
arrived in the 1700’s they
found a mostly barren
landscape, with no trees
over 10 feet tall, yet there
were hundreds of toppled
statues all over the
island.
The few people living on the
island had no horses or
oxen, were using grass to
build fires and lived a
primitive lifestyle.
The mystery: How did the Easter Islanders
build and erect the statues, why did they
do it and what happened to the civilization
that accomplished this?
A tragic metaphor for “Spaceship
Earth” ?
Evidence has been pieced together to
provide the following explanation:
The island was settled by
Polynesians from other islands
around 400 CE.
At that time there were trees,
including palms, on the island as
shown by pollen studies. There is
evidence that land and sea birds
were abundant.
The human population grew as high
as 30,000 as the islanders
harvested dolphins and fish for
food using wooden canoes. They
also ate native island birds and
rats. Farms were started to
provide more food.
A tragic metaphor for “Spaceship
Earth” ?
Like other Polynesian cultures, society
was divided into chiefs and
commoners, which were established
into clans.
On Easter Island, there was
collaboration between the clans, but
also competition that resulted in
building the large stone heads using
rock from an island quarry and
moving them into place on their
territory. One theory is that this
process required many workers to
move them by pulling them along
wooden tracks, possibly on a
wooden sled. All of this required a
huge expenditure of resources to
support the structures and feeding
the workers.
A tragic metaphor for “Spaceship
Earth” ?
Eventually, the island was completely deforested, leading
to local extinction of many species on which the
islanders depended, as well as the loss of the raw
materials to sustain their standard of living.
Deforestation also led to soil erosion and a decrease in
crop yield from farms. Climate change may have
contributed to deforestation.
A tragic metaphor for “Spaceship
Earth” ?
By 1680, civil war replaced the organized clans. People
survived as best they could, raising more domesticated
chickens for food. The statues that had once been
erected as a sign of superiority between clans were then
toppled over by rival clans, and remained as evidence of
the societal collapse when the Europeans arrived.
A tragic metaphor for “Spaceship
Earth” ?
Is this a small scale
model of what could
happen to our planet?
Similarities:
overexploitation of
resources in a fragile,
closed system, with
no where to escape,
no place to get more
resources
Environmental Problems
1. Resource depletion
– Renewable vs nonrenewable
2. Pollution
– Biodegradable vs nonbiodegradable
3. Loss of biodiversity
– Habitat destruction
– extinction
The Good News
Jared Diamond writes in Collapse,
“While we do face big risks, the most serious
ones are not ones beyond our control, ….
Because we are the cause of our environmental
problems, we are the ones in control of them,
and we can choose or not choose to stop
causing them and start solving them.”
Summary
What’s the situation?
• We depend completely on the environment for survival
• We are experiencing increased wealth, health, mobility,
leisure time
• Humans change the environment, often in ways not fully
understood – unintended consequences
• Natural systems have been degraded i.e., pollution,
erosion and species extinction
• Environmental changes threaten long-term health and
survival
• “We are the most dangerous species of
life on the planet, and every other species,
even the earth itself, ha caue to fear our
power to exterminate. But we are also the
only species which, when it chooses to do
so, will go to great effort to save what it
might destroy”
Wallace Stegner
A World Apart
More Money, More Consumers
The countries which have more wealth also use more
of the Earth’s resources. We also produce more of the
substances which may damage the Earth
Affluenza - unsustainable addiction to
overconsumption and materialism
exhibited in the lifestyles of affluent
consumers in the United States and
other developed countries
Ecological Footprint
This is one way to measure our impact on the environment
globally.
What is an ecological footprint?
• the environmental impact of a person or population
• amount of biologically productive land + water for raw materials
and to dispose/recycle waste
Overshoot:
humans have surpassed the Earth’s capacity