Why are the ice caps melting

Why are the ice caps melting?

Planet Earth, where we live, is a remarkable place. As far as scientists are able to tell, this small planet is the only place in the vast universe filled with other planets and stars that has plants and animals. That's because Earth may be the only place where the conditions are just right for living things to exist.

All the different kinds of plants and animals on Earth need an environment that is just right for their needs. Among the things they need in their environment is just the right amount of warmth. If it's too hot or too cold, they can't survive. Many scientists have found evidence in recent years that our planet is growing warmer-too warm, in fact. They call this global warming.

The earth is surrounded by a layer of gases called the atmosphere. Some of the gas is water vapor. The other gases are carbon dioxide, methane, nitrous oxide, and fluorocarbons. These gases form an invisible cover that holds the heat of the sun. Scientists call this the " greenhouse effect. " That's because the gases work something like the glass of a greenhouse. They let in sunlight and keep the sun's warmth from escaping too quickly. a

Everything in nature must be in balance-not too much and not too little. The earth needs just the right amount of the greenhouse effect to be warm enough for living things. But if too much greenhouse gas surrounds the earth, the sun's heat can't escape. The earth will become too warm.

Many different things in nature make carbon dioxide. Human beings and other animals put some carbon dioxide into the atmosphere every time they exhale, or breathe out. Burning coal and oil and automobile gasoline makes much more. Power plants that give us electricity use oil and coal. We also use oil and coal to heat our stores, homes, schools, and offices. Garbage rotting in landfills makes methane gas. Nitrous oxide is released into the atmosphere when we mine coal and dig for oil or natural gas. Fluorocarbons are released when we use some aerosol sprays-these are illegal in many countries now.