Global warming refers to a rise in average global temperature due to human activities: namely, the emissions of greenhouse gases produced by the burning of fossil fuels, and land-use changes like deforestation.

 Energy from the sun drives the earth's weather and climate, and heats the earth's surface; in turn, the earth radiates energy back into space. Atmospheric greenhouse gases (water vapor, carbon dioxide, and other gases) trap some of the outgoing energy, retaining heat somewhat like the glass panels of a greenhouse.
 Without this natural "greenhouse effect," temperatures would be much lower than they are now, and life as known today would not be possible. Instead, thanks to greenhouse gases, the earth's average temperature is a more hospitable 60°F. However, problems may arise when the atmospheric concentration of greenhouse gases increases.

Human activities have altered the chemical composition of the atmosphere through the buildup of greenhouse gases – primarily carbon dioxide, methane, and nitrous oxide. 

What can we do about global warming:
Reduce, reuse, recycle
Consider a fuel-smart car
Think about giving your car a day off
Tune up your home to save dollars
Go solar
Plant trees
Educate others

Additional Resources:
 To learn more about the problem of global warming, click here to go to the Environmental Defense Funds web site.

Environmental Protection Agency has an extensive website dealing with global warming.

Help make the environment safe by  making your home energy efficient, visit the Energy Star website.