Carbon Dioxide and the Farmer's Market

It says here on Al Gore’s website that:

Number of gallons of gasoline is multiplied by the emissions factor of 19.6 to convert to pounds CO2, or 22.4 for diesel vehicles. These emissions factors come from the Energy Information Administration, Fuel and Energy Source Codes and Emissions Coefficients.

According to Terrapass, the fuel efficiency of my 2000 Jetta with a manual transmission and standard gasoline is 24 miles per gallon in the city (which is where I usually drive it).

This means that for every one mile I drive I use 0.0416 gallons of gasoline and emit 0.81536 pounds of C02. Assuming my car is out of tune, and has aged somewhat after 40,000 km of driving, and so has poorer gas mileage than that, a figure of 1 pound per mile driven is probably a reasonable ballpark.

The round-trip from our house to the Charlottetown Farmer’s Market is 3.2 miles, so if we drive we emit roughly 3.2 pounds of C02. Over the course of the year, assuming we drive every week, that adds up to 166 pounds of C02 (or 0.08 tons).

The carbon calculator tells me that my personal carbon emissions are 8.1 tons per year (the big contributors to that are flights to Europe and New England and oil heat in our house).

While we’re heavily abstracted from real numbers by this point, it seems like that driving to the Farmer’s Market every week would contribute about 1% of my annual C02 emissions.

It’s interesting to note that when we moved from rural Kingston to urban Charlottetown seven years ago, I cut out a 6 day a week commute of 20 miles return, resulting in a reduction of roughly 6,240 pounds (or 3 tons) of C02 emissions per year.

Please point out the errors in my math and logic if you find any.