Transcript ch. 20 global climate change

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Introduction to Climate Change
 Causes of Global Climate Change
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Effects of Climate Change
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Melting Ice and Rising Sea Level
Changes in Precipitation Patterns
Effects on Organisms
Effects on Human Health
Effects on Agriculture
Dealing with Global Climate Change
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Greenhouse Gas
 Gas that absorbs infrared radiation
 Ex: Carbon dioxide, methane, nitrous oxide (N2O),
chlorofluorocarbons and tropospheric ozone
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Positive Feedback
 Change in some condition triggers a response that intensifies
the changed condition
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Infrared Radiation
 Radiation that has a wavelength that is longer than that of
visible light, but shorter than that of radio waves…think heat
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Greenhouse Effect
 Increase of heat in a system
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Some evidence for Climate Change
 Temperature increase of 1.4 degrees F since 1880
▪ Extreme northern latitudes – 7.4 increase (40% of N.
polar ice cap melt)
 9 of the 10 warmest years between 2000-2009
 Ice core sampling measures greenhouse gases up to
500,000 years ago. (CO2 and temp. correlate)
 Human produced greenhouse gases are most plausible
explanation
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Greenhouse gas concentrations increasing
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Increased
concentration of CO2
(right)
 Burning fossil fuels in
cars, industry and
homes
 Deforestation
 Burning of forests
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Atmospheric Aerosols tend
to cool the atmosphere
 Both human and natural
sources
 Tiny particles that
remain in troposphere
for weeks or months
 Contain many
chemicals, but often
contain sulfur
Complicates models of
climate change (but
accounted for)
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Climate affected by:
 winds, clouds, ocean currents, and albedo
Used to explore past climate events
Advanced models can project future warming events
Models are only as good as the data and law used to program
them
 They have limitations
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Ocean as CO2 sink - excess CO2 is starting to harm
ocean life (acidification  decline of coral reefs)
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Sea level rise caused in 2 ways
 Thermal Expansion
▪ Water expands as it warms
 Melting of land ice
▪ Retreat of glacier and thinning of ice at the poles
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Melting has positive feedback
 Increased melting decreases ice, which decreases
albedo leading to further warming
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Threatens small islands and coasts: flooding +
erosion and intense storms
1957
1998
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Melting permafrost
 Support structure for Tundra plants,
houses, roads
 Release CO2 and methane from
decomposing material (remember
bacteria decompose more/faster at
warmer temperatures.)
▪ See article
Near Fairbanks, Alaska
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Some areas will get more water, some areas will have
greater droughts
 Ex: Hurricanes will likely get stronger due to warmer water
 Exaggerate El Nino effects
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Zooplankton in parts of California Current have decreased
by 80% since 1951
 Effecting entire food chain
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Polar ice cap melting – too far for Polar bear to swim to
hunt seals
 Polar bear seal (seal carcass to Arctic fox)
Decline in krill around Antarctica
 Caused decrease in penguin populations
Species have shifted their geographic range
Migrating birds are returning to summer homes earlier
 Food is not available at this time
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Coral reefs can be bleached (right) due to
increase in water temperature
 Affects coral symbiotes and makes them more
susceptible to diseases to which they would
otherwise be immune
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Increased number of heat-related illnesses
and deaths: malaria, schistosomiasis, leishmaniasis
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Rise in sea level will inundate/destroy flood plains and river
valleys (lush farmland)
Warmer temperatures will decrease soil moisture- requiring
more irrigation
Location (i.e. elevation and altitude) where certain crops can
be grown may have to change
Difficult to anticipate
 Productivity will increase in some areas and decrease in others
Rising sea levels
Change in precipitation patterns
Sensitive organisms decline; decrease # of organisms at bottom
of food chain
 Increase range of disease causing organisms
 Decrease ability to grow crops in certain areas
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Kyoto Protocol
 Provides rules on reducing greenhouse gases
 US and Australia have not signed it- difficult to implement
without US backing
▪ US concern: LDC not have same expectations to lower
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Two ways to attempt to manage climate
change
 Mitigation/Reduction:
▪ Focuses on limiting greenhouse gas emissions to
moderate global climate change
 Adaptation
▪ Focuses on learning to live with to the environmental
changes and societal consequences brought about by
global climate change
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Locate/invent alternative fuels to fossil fuels
Increase efficiency of cars and trucks
Drive less: bike lanes, carpool, wide sidewalks
Sequestering carbon before it is emitted
Plant and maintain trees to naturally sequester carbon
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Rising sea levels and coastal populations
 Move inland
 Construct dikes and levees
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Adapt to shifting agricultural zones
NYC sewer line