ecosystem: a particular location whose interacting components include living (biotic) and non living...
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Ecosystem: a particular location whose interacting components include living (biotic) and non living (abiotic) components
Environmental Science study of ecosystems (ecology)
Environmentalism social movement that seeks to protect the environment
What is a sustainable system?
one that survives over some specified time that attains its full expected life span
a sustainable society manages it’s economy and population size without exceeding the planet’s ability to absorb environmental insults, replenish its resources and sustain life
Treeless volcanic island2200 miles off the coast of Chili
Moai -Stone Statues that line the perimeter of the island (250) 13 ft high and 14 tons.
Easter Island Story First inhabitants arrived at Easter Island
as early as 318AD. Most believe they were Polynesian, however, some think they arrived from South America.
Between 1400-1600, population was around 9,000.
In 1772, the first European visitors arrived on Easter Island. It was deserted! Barren!
There were signs of deforestation, soil depletion and erosion.
Most archeologist believe the natives cleared the trees for crop land. Planted crops stripped nutrients from the
soil. Clear signs of cannibalism.
LIVING OFF EARTH’S CAPITAL
Do Not eat the goose that lays the golden egg If you have one million in the bank at 10%
interest, you earn $100,000 year. If you spend just $110,000 per year you will be bankrupt in 18 years
Natural cycles will provide for us if we do not destroy our natural capitalDon’t
Eat me
Linear growth vs.exponential growth
linear growth: quantity increases by a fixed amount. EX. 1,2,3,4
Exponential growth: quantity increases by a fixed % of the whole in a given time. EX: 2,4,8,16,32
Fig. 1-2 p. 4Fig. 1-2 p. 4Fig. 1-2 p. 4Fig. 1-2 p. 4
Population is growing exponentially at a worldwide rate of 1.2%. In developing countries it is 1.7%. In developed countries it is .1%.
226,000 more people per day
Fig. 1.1, p. 2
World total
Developingcountries
Developedcountries
9
8
7
6
54
3
2
1
1950 2000
2050 2100
10
developed
developing
world
Fig. 1-3 p. 5Fig. 1-3 p. 5
Fig. 1.1, p. 2
16
15
14
13
12
11
Billio
ns o
f peop
le?
?
?
10
9
8
7
6
5
4
3
2
1
02-5 million
years8000 6000 4000 2000 2000 2100
Hunting and gathering
Black Death–the Plague
Time
Industrialrevolution
Agricultural revolution
B.C. A.D.
70 doubling
% growth rate time in years
70 51.8 years
World Population Growth Rate
1.35 %
An increase in the capacity to provide goods and services for people’s final use
economic growth is measured by an increase in GNP. GNP: gross national product: $ value of goods and
services produced by a country’s businesses within and outside the country
GDP: gross domestic product: $ value of goods and services produced within the country
GWP: gross world product: total $ value of goods and services produced in the world
The problem with GNP is the higher the GNP the more resource depletion and environmental damage. GNP is not the best indicator of quality of life.
per capita GNP: individuals slice of the economic pie
countries are classified as either developing or developed based on their per capita GNP and their level of industrialization developed countries:
U.S., Canada, Japan, Australia, New Zealand, and all of Europe. per capita GNP
greater than $10,000
generate 75% of pollution
use 88% of resources
have 85% of wealth
make up 20% of population
80% of population some are middle income $1,000 to
$10,000 per capita GNP like South Africa, Mexico, Brazil,
Malaysia some are low income with a per capita
GNP of less than 1,000 like India, Pakistan, China
95% of population growth will take place in developing countries
economic growth has allowed us to Live longer be healthier have more
comfort It has not allowed us
to stop
environmental problems
Wipe out poverty
encourages sustainable forms of economic growth that meets the basic needs of the current generations of humans without preventing future generations and other species from meeting their basic needs
discourages environmentally harmful and unsustainable forms of economic growth
it requires that governments, businesses and individuals integrate environmental goals into their decision making process
The Wealth Gap
the gap between per capita GNP or the rich and poor has greatly widened since 1980.
20% high income, 25% moderate income, 30% low income $2-3 / day, 25% very low income of less than $1.00/day.
1 in 5 is hungry, malnourished, lacks access to clean water, decent housing and health care.
Globalization is the broad process of global, social, economic and environmental change that leads to an increasingly integrated world.
A few indicators of globalization: global economy grew from 6.7 trillion to $42 trillion
since 1950
anything that we get from the environment to meet our needs and desires
perpetual resource: something that is continually renewed like solar energy
renewable: On a human time scale something that can be renewed fairly rapidly (Within decades)
biodiversity: variety of life forms that can survive a variety of conditions Genetic diversity species diversity ecological diversity provides free recycling, purification,
resources and pest control
renewable resources can be depleted SUSTAINABLE YIELD: highest rate at which a
renewable resource can be used without reducing its available supply
Tragedy of The Commons by “Garrett Hardin”: Overuse of common property resources, which are owned by no one but available to everyone free of charge. For example clean air, oceans, fish, Antarctica. This leads to exploitation then no one can use the resource. “ If I don’t use this resource then someone else will, the little bit I pollute is not enough to matter”
Fig. 1.11, p. 11
Resources
Perpetual Nonrenewable
Renewable
Freshair
Freshwater
Fertilesoil
Plants andanimals
(biodiversity)
Directsolar
energy
Winds, tides,
flowing water
Fossilfuels
Metallic minerals
Non- metallic
minerals
(iron, copper,
aluminum)
(clay, sand,
phosphates)
- deforestation water logging
or salinization of soil
deforestation pollution reduction in
biodiversity groundwater
depletion Wetlands
destruction
energy resources like coal, gas, uranium which are burned and lost
metallic mineral resources that can recycled
Non-metallic mineral resources that are difficult to recycle
Any addition to air, water, soil, or food that threatens the health, survival, or activities of humans or other animals. It can be natural or from humans
Two types of pollutant sources: point source: where pollutants come from a single
identifiable source, like a drainpipe or a smokestack. Non-point source: pollutants that come from dispersed
sources. Examples are runoff from fertilizers and pesticides or oil from cars.
Two approaches to dealing with pollution: pollution prevention pollution clean-up
rapid population growth rapid and wasteful use of resources with little
emphasis on pollution prevention degradation of life support systems poverty failure of economic and political systems to have
market prices that include environmental costs Our urge to dominate and manage nature for our
use with far too little knowledge of how nature works
Population x Affluence x Technology = Environmental Impact
Air Pollution• Global climate
change• Stratospheric ozone
depletion• Urban air pollution• Acid deposition• Outdoor pollutants• Indoor pollutants• Noise
Biodiversity Depletion
• Habitat destruction• Habitat degradation• Extinction
Water Pollution• Sediment• Nutrient
overload• Toxic chemicals• Infectious
agents• Oxygen
depletion• Pesticides• Oil spills• Excess heat
Waste Production
• Solid waste• Hazardous
waste
Food Supply Problems
• Overgrazing• Farmland loss
and degradation• Wetlands loss
and degradation• Overfishing• Coastal pollution• Soil erosion• Soil salinization• Soil waterlogging• Water shortages• Groundwater
depletion• Loss of biodiversity• Poor nutrition
MajorEnvironmental
Problems
Fig. 1.13, p. 14
United States
The Netherlands
India
CountryPer Captia Ecological Footprint(Hectares of land per person)
10.9
5.9
1.0
Fig. 1.10a, p. 11
CountryTotal Ecological Footprint
(Hectares)
United States
The Netherlands
India
3 billion hectares
94 million hectares
1 billion hectares
Fig. 1.10b, p. 11
Developing Countries
Population (P)Consumptionper person
(affluence, A)
Technological impact perunit of consumption (T)
Environmentalimpact of population (I)
Developed Countries
X
XX
XX
X =
=
=
Fig. 1.15, p. 15
Who should we believe? The precautionary principle Try not to be overwhelmed by the
environmental bad news because there is a lot of good environmental news.
“Never doubt that a small group of thoughtful, committed citizens cannot change the world. Indeed, it is the only thing that ever has”
Margaret Mead
The Invention that changed everything: The plow
Birth rates rose faster than death rates and population increased
People cleared increasingly larger plots of land and destroyed more natural habitat
People began accumulating material goods
Began in England in the mid 1700s Began when England used up all of its forests
and substituted coal for wood Shift from renewable to n on-renewable This lead to growth in mechanization and
factory towns Fossil fuel powered farm equipment lead to
an increased agricultural yield which lead to more people
Reduced infant mortality Raised life expectancy which lead to
more people Better health Birth control Education Affordable goods income
Cultural shift to new technologies such as TV, computers an internet
Hard to know what the impacts will be
Help us understand more about the Earth and how systems work
Allow us to respond to problems faster Use technology to monitor changes in the
Earth More sophisticated technology to model
complex systems Technology to reduce pollution and use
materials more effectively
Cause confusion, distraction, and a sense of hopelessness because of information overload
Increase environmental degradation and homogenization of world cultures
We are developing new technologies before we can evaluate their impact
1870-1900: environmental concern grows because of yellow fever, typhoid fever, cholera, garbage, air pollution, unsafe factories, contaminated water
1891 Forest Reserve Act: established the responsibilty of the federal government to protec public lands
1892: John Muir formed the Sierra club
Fig. 2.6, p. 31
Theodore Roosevelt was president He persuaded congress to give the president the
power to designate public land as wildlife refuges Roosevelt Established the bureau of reclamation He tripled the size of forest reserves 1905: Congress created the US Forest service to
manage and protect forest reserves. Gifford Pinchot was the first chief
1912: US National Park System was created by Congress
The passenger pigeon became extinct
Fig. 2.7, p. 31
Fig. 2.4, p. 30
Preservationists Believed humans
should protect nature, not conquer it
John Muir
Wise Use Believed resources
should be used wisely to enhance the nation’s economic growth
Gifford Pinchot Theodore Roosevelt
Both groups opposed delivering public lands into the hands of a few for profit
Both would be disappointed by what has happened over the years
The 1930s was the great depression and Franklin Roosevelt was president
Aldo Leopold became the leading professional in charge of wildlife management. Set up management plans for the Grand Canyon. Others followed his design
Low cost purchase of large tracts of land from cash poor landowners
Started Civilian Conservation Corp Built large dams to get cheap water to CA Enacted the Soil Conservation Act of 1935 that
was for combating the problem of soil erosion
CCC
Hoover Dam
Rachel Carson published Silent Spring, which documented how DDT was killing wildlife. The beginning of the environmental Era.
1964 Wilderness Act allowed the government to protect large tracts of public land as part of the National Wilderness System
1965-1970 science of ecology was created to understand earth
Cuyahoga River caught fire and burned for eight days
Massive air pollution in New York leaves 300 dead
Lake Erie beaches closed due to pollution
Santa Barbara coastline heavily polluted by leaking offshore oil rigs.
Foam in rivers from pollution
April 20th first Earth Day 1970 Richard Nixon created EPA (the
Environmental Protection Agency 1973 OPEC oil embargo 1974 CFCs found to be creating ozone
hole 1978 Love Canal 1979 Three Mile Island
The Wise Use movement was formed which was an industrial coalition aimed at destroying all the environmental laws
* Goal of Science – creation of a new idea, principle, or model that connects and explains facts and leads to usable predictions about what is likely to happen in nature.
Scientific Method – Observe > Hypothesize > Argue > Test > Hypothesize > Argue > Test
Scientific Theory – an idea or principle, or model that ties together and explains multiple facts that previously appeared not to be related and is supported by a great deal of evidence. (natural selection)
Scientific or Natural Law – a description of what happens in nature time after time in the same way without known exception. (second law of thermodynamics)
Steps 1. Pose a question2. Gather info (knowns)3. What new info/data needs to be gathered?4. Develop a hypothesis that explains data
and predicts new facts. Could there be other explanations?
5. Develop an experiment that can be done to test the hypothesis so it can become a scientific theory.
1. Set up two groups
a. Experimental group – chosen variable is changed in some way.
b. Control group – chosen variable is not changed.
This type of experiment is designed so that all conditions are the same except for the single variable in the experimental group. This is to be sure that the variable is the only factor that could possibly cause any observed change.
2. Set up two groups
a. Experimental group – one group of patients is given a new drug.b. Control Group – similar group of patients is given a placebo (sugar pill).
This is called a double blind experiment because
neither the patient or the doctor is aware of who is receiving the drug or the placebo. This is done to avoid biased results.
Multivariable Analysis – Many of the questions
investigated by environmental scientists involve a huge number of interacting variables (synergism). In multivariable analyses mathematical models run on high-speed computers are used to analyze the interaction of many variables.
1) Disprove2) Establish that a model, theory or law has an extremely high probability of being true.
Nothing can every be proven. Everything we know is just theory. Science is dynamic and changing.
Frontier Science –
“breakthroughs” these are preliminary results that are often controversial because they have not yet been widely tested and accepted.
Consensus Science -
consist of data, theories and laws that are widely accepted within the scientific community because they have been tested and retested or because observations of nature support them.
1. Validity of Data – Difficulty of
Accurate Measurement (soil erosion, species extinction, forest loss)
2. Multiple Variables - not enough
info, difficult to analyze data
Positive Feedback Loop – reinforces itself, a change in a
system, which causes the system to make another change in the same direction (vicious circle). Positive feedback systems destabilize a system. (Easter Island)
Negative Feedback Loop - a change in a system which
results in a change in the opposite direction. Negative feedback loops lead to dynamic equilibrium and homeostasis within a system. (Body Temp)
Fig. 3.4, p. 51
Rate of metabolicchemical reactions
Heat inputfrom sun andmetabolism Heat loss
from aircooling skin
Heat in body
Positive feedback loop
Bloodtemperature inhypothalamus
Excess temperatureperceived by brain
Sweat productionby skin
Negative feedback loop
Synergistic Interaction - two or more processes interact so that the combined effect is greater that the sum of the two parts.
Environmental
Scientists attempt to identify both harmful and beneficial synergisms so that we can:
1. counter harmful ones2. promote beneficial
ones