Greenhouse Effect Intro Greenhouse Earth Greenhouse Effect Intro

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

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

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

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

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:

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

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

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