What are Greenhouse Gases?
The most important is carbon dioxide, also known as CO2. All humans and animals produce CO2 every time we exhale, the but there's nothing we can do about that. The main source of CO2 is the burning of fossil fuels--coal, oil, and gasoline--and wood.
Another greenhouse gas is nitrogen oxide, which is given off by cars as we drive them and by coal-burning power plants as they generate electricity.
Still another is methane, which is created by rotting plants and by household garbage as it deteriorates in landfills. (Humans and other animals also create methane--everytime we pass gas.)
What is the Effect?
We've been creating all of these gases for a long time. But now we're producing too much of them and they are making the Earth a little hotter. Here's what could happen if average temperatures on Earth increases just a few degrees:
Some of the ice around the North Pole and the South Pole would melt.
That melted ice would cause the sea levels to rise.
People living near sea level could be flooded.
Some places would become too hot to live in.
Many farmers' crops would no longer grow.Some scientists now think that the average temperatures on Earth could rise by between 3 and 10 degrees Fahrenheit by the middle of the next century. If that happened, water levels could flood much of New York City. In Washington, D.C., water would flood the Lincoln Memorial and nearly reach the Capitol steps!
That's just the beginning. As things got even warmer, hundreds of different living creatures could die and become extinct, while many kinds of pests (such as rats and mosquitoes) could multiply in the warmer climate.