Air Quality Issues II

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Air Quality Issues II

• Global warming and climate change

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Outline

• Climate
• Greenhouse gases
• Is the earth warming? What do we know for sure?
• Consequences
• Physical
• Biological
• What were pretty sure about!
• What were not so sure about!
• Addressing climate change, can anything be done?

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Climate

• Climate ? weather
• Weather physical conditions
• Climate weather patterns
• Natural Variation - Milankovitch cycles
• Earth orbit moves
• Shifting tilt of earths axis
• Earth axis wobbles
• Ice ages
• Short term variation
• Volcanoes

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The Greenhouse Effect
Fig. 17.18
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Greenhouse gases

• Carbon dioxide (CO2) 67
• Natural but greatest contributor to GW
• Increased by burning of fossil fuels and
  deforestation
• CFCs - 9
• Unnatural
• Potent greenhouse gas
• Methane (CH4) - 18
• Primarily biological termites and rice fields
• Nitrous Oxide (N2O) - 6
• Fossil fuels and fertilizers
• See Table 17.3!

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What is known for sure!

• Steady increase in CO2 levels
• Mauna Loa Observatory Fig 17.19
• Increased global temperature (0.3-0.6 oC in 100
  years
• Humans have caused much of the change
• Global variation in effects, i.e. local effects
  will differ
• Physical changes and Biological indicators

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Physical consequences

• Rising Sea levels
• Glaciers
• Important water source
• Permafrost
• Roads and buildings
• Methane hydrate lots of Carbon Dioxide
• Thinning sea ice Inuit and LEK
• Polar bears
• Northwest passage???
• Global climate patterns
• El Nino/Southern Oscillations
• Pacific Decadal Oscillation
• North Atlantic Oscillation
• wildlife

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Biological Indicators

• Community changes in arctic lakes
• Planktonic food webs (Current Events)
• Plants flower earlier
• Birds and nesting
• Butterflies expanded northward range
• Coral reefs - bleaching

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Biological Indicators

• Boreal and alpine wildlife
• Pikas

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What were pretty sure about!

• How much will the earth warm by?
• Originally 1.5 4.5 oC by 2100
• But estimates are getting more precise
• Increased decomposition of organic carbon in soil
  (1500 Gt)
• Over twice what is in atmosphere (720 Gt)
• Increased extinction rates
• Potential consequences pg 405-408

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What is not known for sure

• Shut down of major ocean currents
• Possible, but not probable
• How fast will the earth warm?
• Hockey sticks and climate change
• Precipitation
• Processes that produce change
• Clouds
• Ecosystems out of synch

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Addressing climate change

• Intergovernmental Panel on Climate Change (IPCC)
• Peer reviewed panel through the UN
• Rio de Janeiro 1992
• Kyoto Protocol 1997
• Signed by Canada, most of Europe, Russia, etc.
• Poor nations are exempt
• Bonn 2001 - ratification
• Implementation
• Global buy into Green Technologies
• Economically infeasible???

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Climate skeptics

• The earth isnt warming
• The warming isnt due to humans
• Kyoto cannot be implemented
• Easier to adapt than to cut GHG emissions
• Spend money on other problems
• Draw your own conclusions but look at the
  credentials