Global Warming _ Climate Change

							Atmospheric Processes Involved
     in Global Warming
         Top issues in science
Alternative energy

                          Global warming




   Stem cells & cloning
           Top issues in science
Genetically modified plants

                              Nanoscience and
                              nanotechnology


Using animals in research
  The public ignores many science issues

Pluto is NOT a planet
                           First face transplant




  Element 118 discovered
But not global warming...
A balanced presentation?
The “truth” in An Inconvenient Truth
Temperature trends
Temperature trends
                           Global Cooling fears
“There are ominous signs that the earth’s weather patterns have
begun to change dramatically and that these changes may
portend a drastic decline in food production ...”




Newsweek, April 28, 1975
Ten hottest years
Ten hottest years
Deadly heat waves
       Extreme high temperatures




        U.S. National Oceanic and Atmospheric Administration



Not one of the world’s highest temperatures has occurred
in the past 30 years!
Hurricane warnings
Hurricane warnings
                     The Deadliest Hurricanes

Galveston hurricane, 1900:      Bangladesh cyclone, 1970:
8,000 killed                    300,000 killed




 Rosenberg Library, Galveston
Deadly weather disasters
               Deadly weather disasters


•   Yangtze River flood, 1931: 3.7 million killed
•   Vietnam flood, 1971:100,000 killed
•   Great Iran Flood, 1954: 10,000 casualties
•   China typhoon 1912: 50,000 killed
•   China typhoon 1922: 60,000 killed
•   India drought 1914: 250,000 died
•   Chinese famine 1907: 24 million died
•   Soviet Union drought 1921-1922: 3 million died
•   Great Drought in western Sahara Desert 1968-1973:
    100,000 died from starvation and disease
    Source: World Meteorological Organization
                 Big Questions

•Why do scientists disagree about the
causes and effects of global warming?

•Why is the issue so complicated?

Kerry Emanuel:
  Phaeton’s Reins: The human hand in climate change

  Boston Review, 2006
  http://bostonreview.net/BR32.1/emanuel.html
                   Climate Change

• The earth is 4.5 billion years old.

• During the past 3,000,000 years, the earth has had both
mild climates and ice ages.
                                  Ice ages




                                        Obliquity (tilt angle) of the earth’s
                                        axis: 100,000 year cycle




Precession (wobbling) of the
earth’s axis: 23,000 year cycle
                                         Eccentricity (shape) of the earth’s
                                         orbit: 100,000 year cycle
The Greenhouse Effect


         Earth with no   l ~ 0.55 mm
          atmosphere
                                       l ~ 10.0 mm




       Earth and
   atmosphere together
               Greenhouse gases
H2O:   • The most important greenhouse substances (liquid and
       vapor).
       • H2O vapor absorbs infrared radiation      warming
       • H2O liquid reflects sunlight into space    cooling
       • H2O is constantly recycled between the atmosphere
       and the oceans
       • The concentration of water vapor is limited by
       temperature


CO2:   • 2nd-most important greenhouse gas
       • absorbs infrared radiation   warming
       • lifetime up to 200 years
Do clouds cool or warm the atmosphere?
              Feedback processes

Positive feedback:      Negative feedback:
an amplifying process   a reducing process
                          Negative feedback: a process
                          that reduces itself
                         body heat
                                       REDUCED




                                       evaporation,
                                       cooling
                       Ice-Albedo Feedback
                      Albedo: % of sunlight reflected.

White surfaces: large albedo.                 Dark surfaces: small albedo.
Ice-Albedo Feedback
Lots of ice in the Arctic
   Ice-Albedo Feedback

Atmospheric temperatures increase



          Sea ice melts


       Albedo decreases


   Earth absorbs more energy
Cloud feedbacks
   Clouds reflect sunlight      cooling
   Clouds absorb IR radiation       warming


   Polluted clouds reflect more sunlight

                                      cooling
               Sulfate (SO4) aerosols




sulfate aerosols reflect sunlight       cooling
sulfate aerosols cause more clouds to form         cooling
sulfate aerosols reduce the size of cloud droplets        cooling
Chaotic system:   • limited predictability
                  • small differences increase quickly
Parameterization
Current status
        So what should we do?
• Elect politicians who understand science
• Conserve the earth’s resources as much as you can
• Pollute as little as you can
• Remember that popular movies and books like
   The Day After Tomorrow and State of Fear are entertainment,
   not science.
                 What else?
• Read what the scientists write (like the IPCC report:
   www.usgcrp.gov/usgcrp/links/ipcc.htm)
• Be skeptical
• Trust your own opinion more than Hollywood’s,
   Michael Crichton’s, or even Al Gore’s
• Enjoy all the beautiful things in life
• Have a nice day!