Global Warming (Climate Change) The Greenhouse Effect Sunlight streams through the atmosphere and heats the Earth. Some of the heat radiates back out into space. The rest of the heat is absorbed by gases in the troposphere and warms the air. The process of heat absorption is called the greenhouse effect

Not every gas in our atmosphere absorbs heat this way. The gases that do not absorb and radiate heat are called greenhouse gases. The major greenhouse gases are water vapor, carbon dioxide, CFC’s, methane and nitrous oxide.

Major Sources of GHG

Rising Carbon Dioxide Levels In 1958 scientists started measuring CO2 levels. It quickly became apparent that the levels where rising.

Fossil Fuels and Climate Change Some scientists believe the increase in CO2 may be linked to increased average atmospheric temperatures. Looking at ice cores have provided some clues to Earth’s past.

Average Global Temperatures on the Rise

Long Term Average Temperatures

Consequences of a Warmer Earth

Melting Ice and Rising Sea Levels Coastal areas would be flooded Coastal aquifers could become too salty Change in Global Weather Patterns Severe storms could occur more frequently and be much stronger Floods could occur in one region while drought devastates other regions

Consequences of a Warmer Earth Risks to Humans Heat could put the very young and very old at risk to excessive heat. May increase ground level ozone Warmer temperature could allow insectbourne diseases to spread

Consequences of a Warmer Earth Agriculture Droughts and floods would decrease food production Higher temperatures would put pressure on water resources

What May Help? Kyoto Protocol- In countries met in Kyoto, Japan to try and reduce CO2 emissions. 55% if attending nations signed the treaty to lower emissions by U.S. did not sign the treaty