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

Change in Carbon Dioxide

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1950 1960 1970 1980 1990 2000

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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

100 million new trees would reduce 18 million tons of carbon in the atmosphere

ReviewGlobal Warming Interactive