Transcript ENVI 30 Environmental Issues - University of San Diego Home Pages

Climate Change – Effects
I.
A.
Negative
5.
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Ozone Holes
Global warming of the atmosphere translates to
stratospheric cooling
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6.
Stratospheric cooling may enhance ozone destruction in
Antarctic and make phenomenon more common in
Arctic (Waibel et al. 1999)
Health
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Consistently elevated temperatures can lead to
immunosuppression
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Exacerbated by elevated levels of UV-B
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Ex – Mass mortality of animals in last 10 years due
to viral infections
- Seals in North Sea
- Lions in Serengeti (Africa)
- Horses in Australia
- Birds in western US
Allergies could worsen due to increased pollen
production, dust (desertification), mold (humidity)
Additional human mortality from severe summer heat
Climate Change – Effects
I.
A.
Negative
7.
•
Tropical Pests and Diseases
Unusual weather favors opportunistic pests
while making life difficult for the predators
that typically control them
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Periods of anomalous weather tend to be followed
by outbreaks of disease
Many tropical diseases are transmitted by
animal vectors – insects, rodents
Climate Change – Effects
I.
A.
Negative
7.
Tropical Pests and Diseases
a.
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b.
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Cholera
1991 – Freighter from Asia emptied bilge tanks off
Peru during an ENSO event
Cholera in bilge water  plankton  shellfish 
humans
500,000+ infected; 5000+ dead
Hantavirus
Late 1980s/Early 1990s – Drought in SW US led to
increase in deer mouse population
Transmitted lethal form of pulmonary hantavirus
To date, hantavirus has appeared in 20 states;
100+ dead
Climate Change – Effects
I.
A.
Negative
7.
Tropical Pests and Diseases
c.
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d.
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Plague
1994 – Unusually long monsoon season in N India
followed by 90 days of temperatures > 100 oF
Heat drove rats into cities  Spread plague
$2 billion to combat problem; 63 dead
Dengue fever
1995 – Rising temperatures allowed a coastal
mosquito species to cross mountains and spread
across Costa Rica, carrying dengue fever
Reached as far north as Texas border
140,000+ people infected; 4000+ dead
Climate Change – Effects
I.
A.
Negative
7.
Tropical Pests and Diseases
e.
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Malaria
Most prevalent vector-borne disease (1-2 million
cases/year)
Transmitted by Anopheles mosquitoes
Warming could lead to
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Broader geographic range (estimate that +2oC could
expand range from 42 to 60% of land area)
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Higher metabolic rate  More food
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Faster maturation  More rapid reproduction
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Faster parasite life cycle
Potential spread into large urban areas (Nairobi, Kenya;
Harare, Zimbabwe) with immunologically naïve pop’ns
Projections are controversial and highly variable
Climate Change – Effects
I.
B.
Positive
1.
Plant Growth
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2.
Warmer temperatures and elevated concentrations
of CO2 lead to faster plant growth and greater food
production per acre
Elevated concentrations of CO2 should lead to
more efficient use of water, reduced runoff and
less water pollution
Enhanced plant growth should remove CO2 from
atmosphere at a faster rate (Gaia Hypothesis)
Agriculture
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Expansion of agricultural regions
Longer growing season in areas that currently are
marginal for agriculture
Climate Change – Effects
I.
B.
Positive
3.
Rainfall Patterns
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4.
Predictions of increased rainfall in major
agricultural regions, especially in northern
hemisphere
Reduced irrigation required for plants/crops
Increased precipitation should cause glaciers and
ice sheets to grow
Milder Winters
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Severe winters pose a health and safety risk
Fewer expenses associated with less severe
winter weather
Climate Change – Projections
II.
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Complexity and uncertainty in climate
models
Response of earth climate system to a
forcing function
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Accumulation of CO2 in the atmosphere
What should we do??
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Lomborg
Air Pollution – Sources & Effects
III.
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Most local air pollution associated with cities,
esp. large cities and industrial centers
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Average concentration of airborne particles in urban
areas ~10x concentration in rural areas
Major cities – air pollution causes thousands of
deaths each year
Mexico City – Air quality so severe that some
people estimate breathing is equivalent to
smoking two packs of cigarettes a day
China – Controversy re: monitoring by Chinese
government vs. US embassy personnel
Many air pollutants are hygroscopic
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Combine with water and promote fog formation
Air Pollution – Components
IV.
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Primary
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Secondary
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Form from precursors
Ex – Ozone
Many are components of photochemical smog
(react chemically with light)
Legislation addressing air pollution requires
consideration of both primary and secondary
pollutants
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Problematic in the form in which they’re produced
Ex – Lead, carbon monoxide
Clean Air Act – 1970
Clean Air Act Amendments – 1990
EPA – NAAQS for six criteria pollutants
Distribution of national total emissions estimates
by source category for specific pollutants, 2010
http://www.epa.gov/air/airtrends