Which car in the 2005 model year produces the smallest amount of greenhouse gases?

Greenhouse gases are the cause of global warming and the vehicles we drive create a lot of those gases. Estimates are that the 2005 Honda Insight, with a combined highway/city fuel economy of 63 miles per gallon, produces only 3.1 tons of greenhouse gas in a year. On average, a light-duty vehicle produces about 9 tons of greenhouse gas in a year.

You may be surprised to learn that most vehicles produce several times their weight in greenhouse gases each year. Not only does most of the fuel you put in your tank become greenhouse gas emissions, but the carbon in the fuel combines with oxygen in the air, almost tripling the weight of the fuel itself.

Estimates of greenhouse gas emissions for specific makes and models are available in our Find and Compare Cars Section

Source:
We've assumed the average vehicle gets 20.8 miles per gallon and travels 15,000 miles per year. Our greenhouse gas estimates are "full fuel-cycle estimates" and include the three major greenhouse gases emitted by motor vehicles: carbon dioxide, nitrous oxide, and methane. Full fuel-cycle estimates consider all steps in the use of a fuel, from production and refining to distribution and final use. This gives a more complete picture of how using a particular fuel contributes to global warming.

These estimates are taken from the U.S. Department of Energy's GREET model, version 1.5 developed by Argonne National Laboratory. Additional information is available at:
http://www.transportation.anl.gov/software/GREET/index.html