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					     Chapter 16
Global Climate Change
     16.1 – Our Dynamic Climate
       16.2 – Climate Change
  16.3 – Effects of Climate Change
16.4 – Responding to Climate Change
  16.1 Our Dynamic Climate
 Energy From the Sun

 Wind Patterns in the Atmosphere

 The Oceans and Climate

 Other Factors that Affect Climate
        Energy From the Sun
 The sun is the source of the energy that
  determines weather and climate on Earth.
 Energy from the sun is transferred to Earth
  by means of radiation.
 About 30% of incoming radiation is reflected
  back into space when it strikes land, water
  or clouds.
 The rest of the solar radiation may be
  absorbed by Earth and the atmosphere and
  converted to heat.
     The Greenhouse Effect in the
            Atmosphere
 The greenhouse effect is a natural process in
  which certain gasses in the atmosphere keep heat
  near Earth and prevent it from radiating into
  space.
 The gasses that do this are called greenhouse
  gasses.
 The major greenhouse gasses are water vapor
  (H20) and carbon dioxide (CO2). Other
  greenhouse gasses include tropospheric ozone
  (O3), nitrous oxide (N2O), and methane (CH4).
  Roles of Greenhouse Gasses
 Greenhouse gasses absorb heat as it is
  radiated off of the Earth’s surface. They
  prevent the heat from radiating into space
  as quickly as it otherwise would.
 Without greenhouse gasses, life on Earth
  would not be possible because the Earth
  would be too cold.
        The Effect of Latitude
 Latitude is a measurement of a place’s
  distance from the equator.
 The equator is located at 0° latitude. The
  degree measure increases as you travel
  further from the equator
 Areas close to the equator are generally
  warm, and temperatures decrease as you
  move nearer to the poles.
          Latitude and Climate
 Latitude effects climate because the sun strikes
  different regions of the Earth at different angles.
 Tropical regions tend to be warm year round
  because the sun’s rays hit the equator most
  directly.
 Temperate zones are areas where you experience
  seasonal temperature changes.
 Seasons change because the angle at which the
  sun’s rays strike the Earth changes as the Earth
  orbits the sun on its axis.
            Sunspot Cycles
 A sunspot is a dark spot on the surface of
  the sun.
 The more sunspots on the surface of the
  sun, the more energy the sun gives off.
 The number of
  sunspots rises
  and falls in
  cycles that last
  about 11 years.
Wind Patterns in the Atmosphere
 Rising warm air and falling cool air in the
  atmosphere create convection currents.
  These currents
  cause winds.
 Prevailing winds
  are formed from
  the rising warm
  air near the
  equator and the
  sinking cool air
  near the poles.
     The Oceans and Climate
 Like winds, ocean currents transport heat
  over long distances.
 Warmer, less salty water moves along the
  surface of the ocean, and colder, saltier
  water moves deep beneath the ocean’s
  surface in a pattern called the thermohaline
  circulation.
 This process causes currents such as the
  Gulf Stream which keeps Europe warmer
  than it would be otherwise.
             El Niño and La Niña
 El Niño is a change in air pressure, wind patterns, ocean
  temperature, and ocean circulation in the Pacific Ocean.
 During El Niño, equatorial winds weaken, and the surface
  water in the eastern Pacific becomes warmer than usual.
 The pattern known as La Niña is the opposite of El Niño.
  Temperatures in the Pacific are cooler than average.
Other Factors that Affect Climate
 Other factors besides the sun, the
  atmosphere, and the oceans affect climate.
 Four of these factors are topography,
  volcanoes, regional distribution of
  vegetation, and changes in Earth’s path
  around the sun.
                 Topography
 A region’s topography describes the surface
  characteristics of the area, including its elevation
  and features such as mountains, rivers, and lakes.
 In general, the greater the altitude, or elevation,
  the cooler the air temperatures will be.
 In general, precipitation falls on the windward
  side of mountains, which is the side that wind first
  passes over.
 The leeward side of a mountain range, or the
  downhill side, gets very little precipitation.
Other Factors that Affect Climate
 Erupting volcanoes expel huge amounts of
  particles that may block out some of the
  sun’s light, having a temporary cooling
  effect.
 Plant life can impact climate by promoting
  rainfall and influencing local concentrations
  of carbon dioxide.
 Minor changes in the Earth’s orbit and tilt of
  Earth’s axis change the distribution of
  sunlight that reaches the surface.
       16.2 Climate Change
 Evidence of a Warming Earth

 Studying Climate Change

 Finding the Cause of Climate Change
  Evidence of a Warming Earth
 When scientists talk about global climate
  change, they are referring to many climate
  characteristics, such as temperature,
  rainfall, wind patterns and storm frequency.
 The term global warming refers specifically
  to an increase in Earth’s average surface
  temperature.
 Global warming is only one aspect of
  climate change.
      Global Climate Change
 The Intergovernmental Panel on Climate
  Change (IPCC) notes that global
  temperature has increased .74°C in the last
  100 years, with the most change occurring
  in the last few decades.
 2005 was the warmest year ever recorded.
 Complex changes in worldwide precipitation
  have taken place.
 Melting Ice and Rising Sea Levels
 Throughout the world, most glaciers are
  shrinking or even disappearing.
 Since 1986, an area in Antarctica known as
  the Larsen Ice Shelf has lost an area more
  than three times the size of Rhode Island.
 Sea levels are rising in many parts of the
  world.
 Expanding sea water (water increases in
  volume as it becomes warmer) and water
  from melting ice caps contribute to this
  issue.
      Studying Climate Change
 Scientists today can collect real-time weather data
  from all over the globe.
 Over many years, this data becomes a record of
  climate patterns.
 Environmental scientists use clues to determine
  weather patterns from the past.
 Proxy indicators are types of indirect evidence
  that serve as proxies, or substitutes, for direct
  measurement.
 Scientists can get proxy information from ice
  sheets, sediments, and tree rings.
          Modeling Climate
 Programs that combine what is known about
  the atmosphere and oceans to simulate, or
  imitate, climate processes are called
  climate models.
 Climate models use enormous amounts of
  data and complex mathematical equations.
 Global climate models can usually produce
  reliable predictions.
     Finding the Cause of Climate
                Change
 In 1958, a scientist named Charles Keeling
  began collecting data on carbon dioxide
  levels in the atmosphere.
 His data showed that there was a
  concentration of carbon dioxide of 315 parts
  per million (ppm).
 In contrast, in 2009, the concentration in the
  same location was 387 ppm.
     Causes of Greenhouse Gas
             Increases
 The main source of extra carbon dioxide in
  the atmosphere is the burning of carbon-
  containing fuels (fossil fuels), such as oil,
  natural gas, and coal for energy.
 Land-use changes, such as the cutting of
  forests, have also caused an increase in
  greenhouse gases.
 16.3 Effects of Climate Change
 Effects on Ecosystems and Organisms

 Impact on People Right Now

 Future Impact on People
       Effects on Ecosystems and
                Organisms
 As ecosystems on land become warmer, some
  organisms have had to shift to places that are
  cooler in order to survive.
 This drives plants and animals toward the poles
  and up mountains.
 Some bird species have changed their migratory
  patterns and timing.
 In the arctic, melting ice is causing problems for
  polar bears. With less ice, bears can not hunt
  seals as effectively and many are dying from
  starvation or exhaustion from swimming long
  distances between sheets of ice.
   Effects of a Changing Ocean
 The ocean is becoming warmer and is absorbing
  more carbon dioxide than ever before.
 Unusually warm water temperatures are causing
  harm to coral reefs.
 Algae that live symbiotically with coral are dying –
  a process called coral bleaching, because
  without the algae, the corals lose their bright
  colors.
 Ocean water is also becoming more acidic as
  more carbonic acid is created in warmer waters.
   Impact on People Right Now
 Droughts have reduced crop yields in many
  areas.
 The forestry industry has been impacted by
  an increase of forest fires as climates are
  warmer and drier.
 Huge storms, such as Hurricane Katrina,
  cause enormous damage with economic
  consequences.
 Extreme heat causes illnesses from heat
  stroke to cardiac arrest.
      Future Impact on People
 The IPCC report indicates that carbon dioxide in
  the atmosphere will continue to rise, and so will
  the temperatures of the atmosphere and ocean.
 The ranges of animals that transmit diseases
  may expand as parts of the world become
  warmer.
 Coastal areas are at risk of serious flooding as
  sea levels continue to rise.
 Fresh water supplies are threatened by
  encroaching sea water and the melting of
  glaciers.
16.4 Responding to Climate Change
 Use and Production of Electricity

 Transportation

 Other Approaches to Reducing
  Greenhouse Gases

 Cooperation Among Nations
 Responding to Climate Change
 We can respond to climate change in two
  basic ways – adaptation and mitigation.
 Adaptation involves protecting people from
  the effects of global warming.
 Mitigation consists of reducing greenhouse
  gas emissions.
 In the long term, mitigation is more
  important because it addresses the causes
  of global warming.
Use and Production of Electricity
 Each person on Earth should be trying to
  reduce their carbon footprint.
 A carbon footprint is the amount of carbon
  dioxide emissions for which an individual or
  group is responsible.
 Electricity generation is the largest source of
  U.S. greenhouse gas emissions.
 Fossil fuel combustion generates about 70%
  of the electricity in the United States.
                Efficiency
 Efficiency consists of using energy
  effectively – that is, accomplishing a job
  using as little energy as possible.
 High-efficiency light bulbs and appliances
  provide a more effective way to use
  electricity.
 Many appliances now earn the Energy Star
  rating which is endorsed by the
  Environmental Protection Agency.
              Conservation
 Conservation consists of reducing energy
  use.
 Individual people can make choices that
  reduce the use of electrical appliances and
  other devices.
  – Turn things off when not in use.
  – Wash only full loads of clothes and dishes.
  – Unplug appliances and chargers when not in
    use.
 Alternate Sources of Electricity
 There are many sources of energy that do
  not burn fossil fuels.
  – Nuclear energy comes from reactions that take
    place within atoms.
  – Solar energy comes from the sun.
  – Wind power depends on wind to create energy.
  – Hydroelectric power uses the movement of
    water.
  – Geothermal energy comes from the heat
    trapped inside the Earth.
             Transportation
 Transportation is the second largest source of
  U.S. greenhouse gas emissions.
 Technology to improve fuel efficiency is
  advancing, but without laws to control
  efficiency, many car makers are not motivated
  to change
  their designs.
 Hybrid, electric,
  or biodiesel
  cars are good
  alternatives.
     Other Approaches to Reducing
          Greenhouse Gases
 Careful farming practices, such as the prevention of
  erosion, help preserve soil’s ability to hold carbon.
 Scientists have developed techniques to reduce the
  greenhouse gases that come from sources such as
  rice cultivation, livestock and manure.
 In a cap-and-trade program, a government puts a
  limit on the amount of greenhouse gases that can be
  released by specific industries and power plants.
  – Industries that release less greenhouse gas than they are
    allowed can sell their leftover allowances to less efficient
    companies.
    Other Approaches to Reducing
          Greenhouse Gas
 A carbon tax is a fee that a government charges
  polluters for each unit of greenhouse gas the emit
  providing a financial incentive to reduce
  emissions.
 A carbon offset is a voluntary payment made
  when one industry or person, instead of reducing
  its own greenhouse gas emissions, pays another
  group or person to do so.
 Carbon sequestration, or storage, consists of
  ways of storing carbon that has been captured or
  removed from power plant emissions.
   Cooperation Among Nations
 The Kyoto Protocol is an international
  agreement that seeks to limit greenhouse
  gas emissions.
  – The protocol is binding, not voluntary.
  – 127 nations have ratified it.
  – Nations committed to reducing emissions to
    below the 1990 levels.
 THE UNITED STATES DID NOT SIGN THE
  KYOTO PROTOCOL!

				
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posted:8/19/2011
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