• Carbon Dioxide from Power Plants
  In 2002 about 40% of U.S. carbon dioxide emissions stem from the burning of fossil fuels for the purpose of electricity generation. Coal accounts for 93 percent of the emissions from the electric utility industry.
   
• Carbon Dioxide Emitted from Cars
  About 20% of U.S carbon dioxide emissions comes from the burning of gasoline in internal-combustion engines of cars and light trucks (minivans, sport utility vehicles, pick-up trucks, and jeeps). Vehicles with poor gas mileage contribute the most to global warming. The United States is the largest consumer of oil, using 20.4+ million barrels per day.

• Carbon Dioxide from Trucks
  About another 13% of U.S carbon dioxide emissions comes from trucks used mostly for commercial purposes.
   

• Carbon Dioxide from Airplanes
  The UN's Intergovernmental Panel on Climate Change estimates that aviation causes 3.5 percent of global warming, and that the figure could rise to 15 percent by 2050.
   

• Carbon Dioxide from Buildings
  Buildings structure account for about 12% of carbon dioxide emissions.
   

• Methane
  While carbon dioxide is the principal greenhouse gas, methane is second most important. Methane is derived from sources such as rice paddies, bovine flatulence, bacteria in bogs and fossil fuel production.
   
• Nitrous oxide
  Another greenhouse gas is Nitrous oxide (N2O), a colourless, non-flammable gas with a sweetish odour, commonly known as "laughing gas", and sometimes used as an anaesthetic. Nitrous oxide is naturally produced by oceans and rainforests.
   
• Deforestation
  After carbon emissions caused by humans, deforestation is the second principle cause of atmospheric carbon dioxide. (NASA Web Site) Deforestation is responsible for 25% of all carbon emissions entering the atmosphere, by the burning and cutting of about 34 million acres of trees each year. We are losing millions of acres of rainforests each year, the equivalent in area to the size of Italy.
   
• City Gridlock
  Cities are tolerating gridlock. Cars and trucks idling, sitting in traffic burn carbon monoxide needlessly.
   
• Carbon in Atmosphere and Ocean
  The atmosphere contains about 750 billion tons of carbon, while 800 billion tons are dissolved in the surface layers of the world's oceans.