Transcript ENVI 30 Environmental Issues

Climate Change – Effects
I.
A.
Sea Level Rise
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Warming  Ice Melt  Sea Level Rise
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Since 1880, sea level rising ~15 cm century-1
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Increased conversion of ice to water
Thermal expansion
Accelerated since 1940s
Melting of all ice should lead to sea level rise of
~70 m
Lomborg – More affluent world should lead to
more protection against effects of sea level rise
http://www.grida.no/climate/vital/19.htm
Climate Change – Effects
I.
B.
Reduced Ice/Snow Cover
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Temperate/Tropical glaciers
Polar ice caps
Holgate Glacier, AK
1909 vs. 2004
Muir Glacier, AK
1941 vs. 2004
After Dyurgerov and Meier (2005)
SAHFOS
European
Space Agency
III. Climate Change – Effects
C.
Extreme Weather
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More and more severe
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Tropical storms
Tornadoes
Increasing economic losses
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Lomborg – Changing population patterns,
demography, economic prosperity
www.ncdc.noaa.gov/oa/climate/research/cei/cei.html
www.hprcc.unl.edu/nebraska/US-tornadoes-1953to-present-bar.html
Climate Change – Effects
I.
D.
Precipitation Patterns
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Warming should lead to
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Reduced precipitation at low latitudes
Increased precipitation at high latitudes
Examples
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Drought in many parts of the world
Reduced snowpack in Sierra Nevada Mountains
due to rainfall instead of snow
Increased agricultural production in some areas
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Combined with higher temperatures and [CO2]
20th Century
Source: U.S. Global Change Research Program
Source: U.S. Global
Change Research
Program
Climate Change – Effects
I.
E.
Ozone Holes
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Global warming of the atmosphere
translates to stratospheric cooling
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Stratospheric cooling may enhance ozone
destruction in Antarctic and make phenomenon
more common in Arctic (Waibel et al. 1999)
Climate Change – Effects
I.
F.
Ecosystem Effects
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Expand ranges of warmth-tolerant species and
contract ranges of warmth-intolerant species
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Within an ecosystem, some species more sensitive to
climate change than others
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Colder-living species might be displaced poleward as
well as upward in elevation
Species unable to adapt or move would go extinct
Species composition of communities almost certainly
will change
Ex: Intertidal (Pacific Grove – Central CA)
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Significant abundance changes in 32/45 species
between 1931 and 1994
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8/9 southern species increased significantly
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5/8 northern species decreased significantly
Changes in CO2 concentration  lower pH of ocean
Behavioral changes (Ex: Sockeye salmon)
I.
Climate Change – Effects
G. Health
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Consistently elevated temperatures can lead
to immunosuppression
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Exacerbated by elevated levels of UV-B
Allergies could worsen due to increased
pollen production (heat), dust (drought),
mold (humidity)
Additional human mortality from severe
summer heat
U.S. Global Change
Research Program
Climate Change – Effects
I.
H.
Tropical Pests and Diseases
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Many tropical diseases transmitted by
animal vectors – insects, rodents
Concern that global warming could increase
geographic ranges of vectors
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a.
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Dengue fever
Ex: 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+ died
Climate Change – Effects
I.
H.
Tropical Pests and Diseases
b.
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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