Climate Change

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• Climate Change Effects
• Sea Level Rise
• Warming ? Ice Melt ? Sea Level Rise
• Increased conversion of ice to water
• Thermal expansion
• Since 1880, sea level rising 15 cm century-1
• 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

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http//www.grida.no/climate/vital/19.htm
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• Climate Change Effects
• Reduced Ice/Snow Cover
• Temperate/Tropical glaciers
• Polar ice caps

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Holgate Glacier, AK Muir
Glacier, AK 1909 vs. 2004
1941 vs. 2004
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After Dyurgerov and Meier (2005)
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SAHFOS
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European Space Agency
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• Climate Change Effects
• Extreme Weather
• More and more severe
• Tropical storms
• Tornadoes
• Increasing economic losses
• Lomborg Changing population patterns,
  demography, economic prosperity

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www.ncdc.noaa.gov/oa/climate/research/cei/cei.html
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www.hprcc.unl.edu/nebraska/US-tornadoes-1953to-pre
sent-bar.html
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• Climate Change Effects
• Precipitation Patterns
• Warming should lead to
• Reduced precipitation at low latitudes
• Increased precipitation at high latitudes
• Examples
• 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
• Combined with higher temperatures and CO2

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20th Century
Source U.S. Global Change Research Program
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Source U.S. Global Change Research Program
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• Climate Change Effects
• Ozone Holes
• Global warming of the atmosphere translates to
  stratospheric cooling
• Stratospheric cooling may enhance ozone
  destruction in Antarctic and make phenomenon more
  common in Arctic (Waibel et al. 1999)

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• Climate Change Effects
• Ecosystem Effects
• Expand ranges of warmth-tolerant species and
  contract ranges of warmth-intolerant species
• Colder-living species might be displaced poleward
  as well as upward in elevation
• Species unable to adapt or move would go extinct
• Within an ecosystem, some species more sensitive
  to climate change than others
• Species composition of communities almost
  certainly will change
• Ex Intertidal (Pacific Grove Central CA)
• Significant abundance changes in 32/45 species
  between 1931 and 1994
• 8/9 southern species increased significantly
• 5/8 northern species decreased significantly
• Changes in CO2 concentration ? lower pH of ocean
• Behavioral changes (Ex Sockeye salmon)

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• Climate Change Effects
• Health
• Consistently elevated temperatures can lead to
  immunosuppression
• 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

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U.S. Global Change Research Program
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• Climate Change Effects
• Tropical Pests and Diseases
• Many tropical diseases transmitted by animal
  vectors insects, rodents
• Concern that global warming could increase
  geographic ranges of vectors
• 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

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• Climate Change Effects
• Tropical Pests and Diseases
• Malaria
• Most prevalent vector-borne disease (1-2 million
  cases/year)
• Transmitted by Anopheles mosquitoes
• Warming could lead to
• Broader geographic range (estimate that 2oC
  could expand range from 42 to 60 of land area)
• Higher metabolic rate ? More food
• Faster maturation ? More rapid reproduction
• Faster parasite life cycle
• Potential spread into large urban areas (Nairobi,
  Kenya Harare, Zimbabwe) with immunologically
  naïve popns
• Projections are controversial and highly variable

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Climate Change Effects