Chapter 18 Global Climate Change by zhouwenjuan

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									Chapter 18: Global Climate
Change
Climate

   area's long-term atmospheric conditions
    –   temperature
    –   humidity
    –   wind
    –   precipitation
    –   barometric pressure
    –   solar radiation
   global climate change sees all these factors but
    considering the whole planet
Global Warming

   increase in Earth's average surface
    temperature only
Rate of Atmospheric Changes

   climate varies naturally overtime
   the rate has increased
   fossil fuel combustion and deforestation
Factors that Influence Climate

   Milankovitch cycles
   affect intensity of solar radiation
   cause long-term temperature changes like
    glaciation
    –   axial wobble→ 19 to 23,000 year cycle
    –   variation in tilt→ 41,000 year cycle
    –   variation in orbit→ 100,000 year cycle
Factors that Influence Climate

   ocean absorption
    –   CO2 is soluble in ocean water
    –   but as temperature increases solubility decreases
    –   phytoplankton absorbs some in photosynthesis
    –   but not enough to compensate the extra CO2
        produced today
    –   positive feedback effect
Factors that
Influence Climate

   ocean currents
   El Niño                                                   www.noaa.gov




    –   air pressure decreases in western Pacific
        weakens the equatorial winds
        warm water flows east towards America
        shuts down delivery of nutrients
        fish population plumbs
        ocean birds, reptiles and mammals are also affected
        causes billions of economical losses
Factors that
Influence Climate

   La Niña
                                                  www.noaa.gov
    –   opposite of El Niño
    –   cold waters extend to the west
•   El Niño/La Niña occur in cycles but these have
    become irregular
•   Scientists are investigating if there is any relation
    between irregularity of phenomena and air/water
    temperature increases
Thermohaline Circulation




                           www.aw-bc.com/Withgott
Thermohaline Circulation

   interruption might trigger rapid climate
    change (hypothesis)
   data suggest circulation is slowing down
Study of Climate Change

   proxy indicators: indirect evidence
    –   ice cores
    –   tree rings
    –   sediment beds
    –   coral reef
Study of Climate Change

   direct atmospheric sampling
    –   studies present-day climate
    –   measures conditions of the atmosphere
            concentrations of CO2
            monitoring of temperature
Study of Climate Change

   Climate Models
    –   simulations
    –   mathematical
    –   sophisticated computer programs that combine
            atmospheric circulation
            ocean circulation
            atmosphere-ocean interactions
            feedback
            old data is used to see if the model works before it is
             applied
Current Climate Change Impacts

   international panel of scientists (IPCC)
   Fourth Assessment Report of 2007 (fig.
    18.12)
   contains thousands of studies
   includes some predictions
   addresses impacts of current and future
    climate changes
   discusses possible strategies
Temperature Increase

   most of the increase occurred in the last few
    decades
   1995-2006 were among the warmest on record
   the number of heat waves have increased
   a temperature increase of 0.2ºC is expected per
    decade if there is no control of emissions
   IPCC predicts that by 2100 temperature will rise 1.8-
    4ºC depending on the emission scenario
Temperature Increase

   Arctic changes of up to 3ºC are causing:
   ice melting earlier
   forming later
   ice area is decreasing
   thinner ice
   no food for Inuit people
   no food for polar bears
   permafrost is melting
    Projected Temperature Changes
     for the decade of 2090-2099
       www.aw-bc.com/Withgott




    IPPC calculates an increase of 0.1ºC per decade during the 21st century
    If we don't control the emissions it might get to an increase of 4ºC
    Ocean temperature is also increasing causing more intense hurricanes
Changes in Precipitation
                                           www.aw-bc.com/Withgott




It is predicted to increase at high latitudes and decrease at low and middle
Will worsen water shortages near the tropics
Away from the tropics heavy precipitation will become more frequent
increasing chances of flooding
Droughts will become more severe and frequent
Melting Ice and Snow

   risks of sudden floods
   ice dams burst
   reduction of summertime water supply
   Artic/Antarctic ice surface is decreasing
    –   resulting in larger darker ocean surfaces which capture heat
        and melt the ice faster
    –   more dark surfaces on Earth reduces the albedo effect (light
        reflection)
    –   as a result Earth's surface increases in temperature
    –   positive: new shipping lanes and possible sites for oil and
        gas exploration
Rising Sea Levels




 1938                1957               1972                1988

Backwater National Wildlife Refuge in Maryland
marsh loss can occur if the rise is so fast that plants can't adapt
Rising Sea Levels

   increase in level worldwide (17cm=6.7 in)
   caused by
    –   melting of ice
    –   increase in runoff
    –   increase in temperature→causes expansion of
        the volume of water already there
Problems with Rising Sea Levels

   beach erosion
    –   Florida, Washington, California, Texas, etc.
   coastal floods
    –   Venice, Italy
   intrusion of salt water into aquifers
    –   Los Angeles
   loss of wetlands (mangroves)




    Guayaquil, Ecuador
    1985 & 2000
   loss of coral reefs
    –   Maldives
   possible evacuations and migration of people
    –   Island nations of Tuvalu and Maldives
Climate Change Effects on Organisms
& Ecosystems

   alterations of the environment affect living
    organisms
   adaptations take generations to acquire
Changes Attributed to Climate Change

   temperature-dependant
   plants blooming timing
   animals breeding timing
   birds migration timing
   insects hatching timing
   plants and animals are migrating north or
    higher elevations
   bleaching of corals
Societal Impacts

   Agriculture Related
   earlier crop planting
   shift of seasons
   droughts and floods become more severe
   predictions say production may increase but only
    temporarily
   tropical and subtropical regions will lower production
    due to drought
   hunger will increase
   Forestry                                   Asian long horned beetle

   longer & drier fire season
          El Niño 97-98
   invasive species are more common
          zebra mussel has arrived to Texas (4/09)
                                                          zebra mussel
          found in lake Texoma
   insect and diseases are more frequent
          elm trees
                                                     www.aw-bc.com/Withgott




   Health Issues                Deaths attributed to hot weather
   respiratory diseases
   more frequent
   expansion of tropical diseases
   floods overcoming sewage treatment
           cholera
   drowning more probable
   hunger/ malnourished
Economics

   people's perception of greenhouse effects has
    shifted
   insurance companies began noticing increase in
    weather related disasters
   industry also changed its point of view
   An Inconvenient Truth helped spark the interest
   companies are asking for legislation to require
    significant reduction in greenhouse gas emittions
Responding to Climate Change

   mitigation or adaptation?
   mitigation: pursue actions that reduce
    greenhouse gas emittions
    –   energy efficiency
    –   switching to clean renewable energy
    –   farm practices that protect soil and water quality
    –   prevent deforestation
    –   recovery of gasses from landfills
   adaptation: lessen the impact of future
    climate changes
    –   seawall in Galveston
    –   restricting coastal development
    –   adjusting farm practices to drought conditions
    –   modification of water management due to water
        conditions (floods, drought and salt intrusion)
Electricity Generation: Source of
Greenhouse Gasses

   it is the largest source (40%) of greenhouse
    gasses in the U.S.
   69% of the electricity in the U.S. is generated
    by fossil fuels. 50% is from coal.
   ways to lessen the amount of fossil fuels
    used
    –   encouraging conservation
    –   switching to cleaner and renewable sources
Conservation and Efficiency: Saves
Money in the Long Run

   new technologies
    –   high-efficiency light bulbs for example
   ethical choices
    –   EPA's Energy Star Program
            more efficient electric appliances
            efficient heating and cooling systems
            efficient office equipment
    –   turn off lights when not in use
    –   turn off equipment when not in use
Sources of Electricity: Cleaner is
Better

   altering the types of energy we use
   coal→oil→natural gas
   natural gas produces half the emissions that coal
    produces
   carbon sequestration (or carbon capture) will reduce
    the CO2 emitted to the air
   use of OTHER energy sources
    –   nuclear power   hydroelectric   geothermal
    –   wind power      ocean tides     photovoltaic
Transportation

   second-largest source of greenhouse gasses
   1/3 of the average American city is devoted
    to car use
   average American family makes 10 trips/day
   in the U.S. $200 million is spend daily in
    construction and repairs
Typical Automobile is Inefficient




www.aw-bc.com/Withgott
Automotive Technology

   fuel-efficient vehicles
   hybrids
   fully electric
   alternative fuels (hydrogen cells)
Public Transportation

   it is a lifestyle choice
   car use decreases if living near their workplace
   cities are working on the use of mass transit
   people are including bike or walk
   it is not accessible to everyone
    –   Arlington refuses to include the train and bus system
    –   Allen refuses to include the DART train system
Strategies to Reduce Emissions

   double fuel efficiency in vehicles
   decrease the miles you drive daily
   maximize efficiency in buildings
   double efficiency in coal power plants
   switch from coal to natural gas
   capture and store carbon dioxide (sequestration)
   increase nuclear power production (3x)
   increase wind (50x) & solar (700x) energy production
    halt tropical deforestation
    adopt conservation tillage on croplands
Mandates, Incentives or Both?

   commandment-and-control policy
   mandates are often resisted by industry
   incentives may be more effective
   whatever desition it has to be
    –   fair
    –   economically palatable
    –   effective
    –   enforceable
International Treaties

   1992 U.N. Framework Convention on
    Climate Change- voluntary approach
   by 2006
          U.S. has increased its emissions by 17.9%
          Germany decreased its emissions by 17.2%
          U.K. dropped its emissions by 14.3%
1997 Kyoto Protocol


 –   mandates reduction of emittions to those of 1990
 –   reduction must be accomplished by 2008-2012
 –   U.S. refused to ratify accusing China and India
     of polluting without having to follow the protocol
 –   creating resentment with allies
 –   emittions had increased 11% worldwide by 2004
Climate Change Policies from Cities
and States

   in responce to inaction from the G.W. Bush
    administration and Congress
   "meet or beat" Kyoto Protocol guidelines
    –   mayors of 600 cities
    –   urging state and federal government to act
            California passed the Global Warming Solutions Act in
             2006- 25% reduction of greenhouse gasses by 2020
            cap-and-trade program in the NE
Carbon Offset: Key to Mitigating

   voluntary payment
   pays the entity that is willing to reduce
    emissions that one in not willing to do
   becoming very popular
   carbon-neutrality: no net carbon is emitted
   now it may not be as efficient as thought
   has to be transparent and enforceable
Carbon Footprint

   individual everyday life choices
   reduce the emissions you create
   transportation
   EPA Star Program


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