Did you know: The United States is the largest consumer of oil

About 33% of U.S carbon dioxide emissions comes from the burning of gasoline in internal-combustion engines of cars and light trucks (minivans, sport utility vehicles, pick-up trucks, and jeeps).Vehicles with poor gas mileage contribute the most to global warming.

Source: http://www.nrdc.org/globalWarming/f101.asp

Meaning of "Global Warming"

Earth is warmed by heat-trapping gases. These Heating-trapping gases are known as greenhouse gases. They exist in the earth’s atmosphere. Greenhouse gases have kept the temperature of the planet in a series opening for life as we know it. Due to human activity, levels of greenhouse gases, such as carbon dioxide, have been increasing in the atmosphere. This increase threatens to make Earth warmer than it has been for millions of years. From the results of these crises, the greenhouse has also affected the sea level.

Source: http://www.weatherquestions.com/What_is_global_warming.htm