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 levelswhere rising.

Fossil Fuels and Climate Change

Some scientists believe the increase in CO2 may be linked to increasedaverage 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

Consequences of a Warmer Earth

Melting Ice and Rising Sea LevelsCoastal areas would be floodedCoastal aquifers could become too salty

Change in Global Weather PatternsSevere storms could occur more frequentlyand be much strongerFloods could occur in one region while drought devastates other regions

Consequences of a Warmer Earth

Risks to HumansHeat could put the very young and very oldat risk to excessive heat.

May increase ground level ozone

Warmer temperature could allow insectbourne diseases to spread

Consequences of a Warmer Earth

AgricultureDroughts and floods would decrease foodproduction

Higher temperatures would put pressure on water resources

What May Help?

Kyoto Protocol- In 1997160 countries met in Kyoto, Japan to try and reduce CO2 emissions.55% if attending nationssigned the treaty to loweremissions by 2012. U.S. did not sign the treaty