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Global Climate Change

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Title: Slide 1 Author: wcpss Last modified by: WCPSS Created Date: 4/7/2008 9:49:28 PM Document presentation format: On-screen Show Company: wcpss Other titles – PowerPoint PPT presentation

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Title: Global Climate Change


1
Global Climate Change
  • How climate has changed during the last million
    years
  • The science behind human induced global warming
  • Positive and negative feedback cycles in the
    atmosphere and their effect on global temperature
    change
  • Adjusting to global temperature change
  • Mitigation

2
Climate change
3
Low temp- glacial periods Higher temp-
interglacial period
4
Last continental ice age
1100-1300 Vikings colonize Iceland, Greenland,
N. America
Abandonment of settlements
5
Mid-1970s warming 3x more rapid than preceding
100 years
Last 100 years change in temp of 0.6 degrees
6
Why does climate change occur?
  • Milankovitch hypothesized that the wobble of the
    Earth changes the amount of sunlight reaching the
    Earth
  • Occurs in cycles of 20 to 40 thousand years
    corresponding to the global ice ages

7
Monitoring global climate change
  • Geologic record- glacial ice bubbles
  • Real-time monitoring- Mauna Loa
  • Mathematical modeling- global circulation model

8
20 layers data Temperature Dendrology Winds Cells
size Idaho
9
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10
Science of Global WarmingPositive and negative
feedbacks
Global responses to GCC Negative- help
stabilize global temperature change in response
to warming scenario Or Positive-
self-enhances increases an already increasing
temperature
11
Negative feedback
  • Increase in algae growth algae absorb more
    CO2 reduce atmospheric
  • CO2 Cooling temperatures
  • 2. Increase CO2 increased vegetation
    growth facilitate atmospheric cooling
  • 3. Increase moisture at poles increased
    snow increased radiation reflected from
    Earth temperatures cooled
  • 4. Higher temperatures more cloud cover
    clouds reflect UV light
  • temperatures cool

12
Positive Feedback
5. Increased water evaporation from oceans
add water vapor to atmosphere water
vapor causing warming 6. Methane released
melting permafrost increased
temperature 7. Reduced snow pack reduce
solar reflection from Earth 8. Higher
temperatures use more AC burn more fossil
fuels increase CO2 increase temperatures
13
Adjustments to Potential Global Warming
Change in biomes Deserts expand Tundra lost
Some regions dry, some wetter
Decrease food production/changing regions food
production
Diseases Eroding shoreline
14
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15
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16
Mitigating Global Warming
  • FACTS
  • US 5 world population 20 atmospheric carbon
    dioxide
  • Hague meeting in 2000 refused to honor 1997 Kyoto
    protocol CO2 emissions agreement
  • 180 countries signed agreement, including Russia

17
Emissions trading Cap and trade' system-
requires countries to reduce their emissions
5.2 below their 1990 baseline over the 2008 to
2012 period. (US increase CO2 emissions 6.5
over 1990 level) Carbon credits- Companies can
purchase credits directly from another party
with excess allowances carbon credits that
represent a reduction of CO2 emissions. Can be
traded on stock exchange
18
Copenhagen U.N. Climate Conference- 2009
  • 192 countries
  • 10 billion per year fund to assist developing
    nations reduce GH gases
  • Denmark, Sweden, Britain-3.5 billion
  • Earmarked to combat effects global warming and
    decrease emissions
  • Disease
  • Irrigation and cropping shifts
  • Coastal Protection
  • Shift from fossil fuels to low carbon systems

19
Copenhagen U.N. Climate Conference- 2009 contd
  • Reduction Emissions from Forest Degradation
  • Why? 20 of GH gases from release of carbon from
    deforestation

20
MitigationHow do we reduce emissions??????
Deforestation
Carbon dioxide storage
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