1. Greenhouse Effect Intro
Greenhouse Earth
Greenhouse Effect Intro

2. Greenhouse Effect
The earth’s atmosphere traps sunlight like glass on a greenhouse
The Earth absorbs the heat and releases it to warm the air
The rest of the heat gets trapped by the gases in the troposphere
Some gases radiate heat instead of trapping them – these are the greenhouse gases

3. Major greenhouse gases:
Water Vapor H2O
Carbon Dioxide CO2
Chlorofluorocarbons CFC’s
Methane (natural gas) CH4
Nitrous oxide NO2
Ozone (in the troposphere) O3
Water vapor and CO2 are the most abundant

4. How can we tell how much CO2 is in the atmosphere?
Carbon dioxide naturally fluctuates
Photosynthesis, pollutants
1958 – Charles Keeling measured the CO2 in the air at Mauna Loa in Hawaii
Reasoning – the air comes from the Pacific, far from forests and cities
Most accurate representation of the atmosphere
March 1958 – 314ppm
(.0314%)
An increase was seen in only a few years
1968 – 320ppm
1978 – 332ppm
1988 – 348ppm
1994 – 358ppm

6. Greenhouses gases trap heat near the surface
More greenhouse gases = warmer Earth
We are releasing more CO2 into the atmosphere than ever before
Prediction – Earth’s temperature will increase by 4º by 2050
This predicted increase in temperature is known as global warming

7. The Earth has had drastic changes in its climate in the past
Ice ages
These took thousands of years
No one is sure what the effects of global warming will be or how severe
Computer simulations tell us:

8. Weather
If the Earth heats up significantly, oceans will warm which will make hurricanes and typhoons more common
If the weather patterns are affected, it could change the ocean patterns
Disruptions in weather would affect agriculture – farming weather may shift Northward; out of the Midwest

9. Oceans Polar ice caps melt and raise sea levels
Glaciers – mass of ice and snow on land
Iceberg – chunk of glaciers that breaks off and falls into the water
Higher sea levels would cause parts of land to be covered
California, Louisiana, parts of Florida
US is shrinking

10. STOP IT! Reduce burning fossil fuels Plant more trees Review
100 million new trees would reduce 18 million tons of carbon in the atmosphere
Review
Global Warming Interactive