What the EPA says...

For the past couple hundreds of years, humans have been burning fossil fuels which have significantly increased the level of greenhouse gases in the atmosphere. Greenhouse gases are necessary to a certain extent, because if we didn't have them the earth would be too cold to live on, but too many of them is a bad thing because the temperature can rise so much that everything and everyone dies, so the earth needs a happy medium. It's kind of like calories, if you eat too many you get fat, but if you don't have enough then you have to energy to fuel your body, so you need just the right amount. The United States has a policy in order to help global warming and decrease the amount of greenhouse gases. The three components of it are to slow the growth of emissions, strengthen science, technology, and institutions, and to enhance international cooperation. In the United States, the energy-related activities we partake in account for 3/4 of human generated greenhouse gas emissions. The health effects of global warming are very important because the rising temperatures can increase the number of people with asthma or make it worse, there could be more incidents of heat stroke and death, and climate related diseases can be spread easier.

Basically they say the same thing everyone elso does - global warming is bad.

U.S. Environmental Protection Agency. Basic Information - Climate Change. Retrieved February 22, 2008, fromhttp://www.epa.gov/climatechange/basicinfo.html