Transcript ENVI 30 Environmental Issues

I.
Criteria for Crisis
C.
Overuse and Pollution of Fresh Water
1.
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PROBLEM
Extensive contamination of ground water
Depletion of aquifers
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Subsidence of ground in some areas
Overuse of fresh water resources
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Ex: Colorado River
Ex: Jordan River
I.
Criteria for Crisis
C.
Overuse and Pollution of Fresh Water
2.
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NO PROBLEM
Still plenty of fresh water in most areas, and
new delivery methods work well
New purification techniques offer promise for
the future
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Desalination
Reclamation (“Toilet to Tap”)
I.
Criteria for Crisis
D.
Deforestation
1.
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PROBLEM
Forested area has been shrinking for
centuries, and rate of deforestation has
increased dramatically in past 50 years
Less than 20% of original forest cover
remains in many countries
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Philippines, Madagascar, Scotland
Health of forests declining as well
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US Forest Service estimated growth rate of yellow
pines in SE United States declined 30-50%
between 1975 and 1985, while fraction of dead
trees increased from 9% to 15%
1945
1960
1974
Bahia
http://www.nybg.org/bsci/res/bahia/Defor.html
1990
I.
Criteria for Crisis
D.
Deforestation
2.
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NO PROBLEM
Globally, replanting more than makes up for
deforestation
Managed properly, the cultivation of trees as
an agricultural crop (silviculture) makes good
use of a valuable renewable resource.
I.
Criteria for Crisis
E.
Global Climate Change
1.
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PROBLEM
Lester Milbrath (SUNY Buffalo)
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“Devastation from climate change will be
exacerbated by other global biospheric effects: loss
of the ozone layer, acid rain, poisonous red tides of
algae, toxic pollution of soil, water, and air, and
species extinction."
data.giss.nasa.gov/gistemp/graphs/
I.
Criteria for Crisis
E.
Global Climate Change
1.
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PROBLEM
Effects
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Rise in sea level (ca. 3-4 mm y-1)
Shifting of climate zones
Widespread drought in agricultural regions
Declining populations of marine plankton
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Additional effects through food web
Increased summer deaths from heat
I.
Criteria for Crisis
E.
Global Climate Change
2.
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NO PROBLEM
Rush Limbaugh
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Environmentalists are guilty of exaggerating
the gravity of the situation
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Present hypotheses as certainties and predictions
as facts
Misrepresent evidence and compromise credibility
Current climate models aren’t complete
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“Global warming is a scam invented by
environmental scientists to increase their research
funding”
Only account roughly for role of ocean as a
reservoir for heat (ATOC)
Climategate!
I.
Criteria for Crisis
F.
Energy Availability
1.
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PROBLEM
“If it were not for the world's predominant reliance on
fossil fuels for transportation and energy generation, the
problems of global warming, acid rain and urban smog
would be relatively minor”
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Energy costs should be adjusted to reflect the environmental
costs associated with their generation
Renewable energy resources need to be encouraged
2005: Growing energy demand in the US will require the
construction of 250 large coal or nuclear power plants (or
their equivalent) by the year 2015
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Nuclear fission plants are unsafe and produce hazardous
waste that requires long-term secure storage
Hydroelectric facilities produce no GHGs but are
environmentally problematic
I.
Criteria for Crisis
F.
Energy Availability
2.
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NO PROBLEM
New and alternative technologies offer promise
for the future
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Natural gas
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Requires expansion of infrastructure
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Requires new technology (hydrofracking)
Nuclear power (with proper regulation and security)
Solar power
Energy from the sea
Fuel cells
II.
Population Dynamics - History
A.
Thomas Malthus (1766-1834)
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English parson
Became concerned that unrestricted population
growth would cause demand to exceed
availability of resources
Predicted widespread poverty and famine
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Global population < 1 billion
Malthusians - People who forecast disaster due
to overpopulation
Many of Malthus’ predictions did not occur
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Agricultural improvements (did not foresee)
Birth control (rejected on moral grounds)
II.
Population Dynamics - History
B.
Demographic Transition
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Theory developed to explain human population dynamics
in response to economic development
Cohen – Four Stages
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1)
2)
3)
4)
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High birth & death rates (nearly equal but variable) 
Growth rate low
Death rate falls and becomes less variable, birth rate still
high  Growth rate rises, population increases.
Mortality transition
Birth rate drops, death rate remains low or declines, growth
rate slows, population increases. Fertility transition
Low birth & death rates (nearly equal, not variable), growth
rate low or negative, population larger than before (1)
This process has occurred in many developed nations
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United States, Canada, Japan, Western Europe