Carbon Footprint Calculators

Here are a few carbon footprint calculators, with the pluses and minuses of each:

Al Gore's site:

The advantages to this site are that it is easy to enter revised figures, it's easy to use, and it's fast. You can quickly see the effect of adding or subtracting one airline flight a year, or changing the model of car that you drive. One disadvantage is that there is nothing about consumption- the site only includes transportation (car and airplane) and home energy use. I do wonder how accurate it is- the site doesn't allow you to enter exact values. I suspect I may have gotten more credit for efficiency with my Prius than I really get.

EPA:

This site is also easy to use, and it suggests actions to take and calculates the reduction to your footprint that these actions would cause. However, it doesn't automatically recalculate if you change one of your entries- you have to refresh the entire page. Air travel is not included, and there is a lot of emphasis on recycling, but not on reducing use in the first place. And it doesn't include anything about the consumption of goods.

Cool California:

This was the most difficult site to use: you have to enter information on various screens, and on dial-up this was excruciatingly slow. It also uses your annual income to preset average values-- you then have to override if your figures are different. Though I appreciated that they were trying to account for consumption, I found the screens for goods and services to be confusing and hard to estimate. I also didn't like that they don't use the same format for all graphs. They use a vertical bar graph and a pie chart for your individual results, and use a horizontal bar graph for comparison to average state, country, and world consumption.

Atmosfair:

It has a nice graph comparing the carbon footprint of airline flights to car use, refrigerator output for a year, and the average annual emissions of an Indian. On the downside, the comparisons were all in euros and kilograms. The Al Gore site has a link to a flight calculator that is in "American."

All of the sites give widely diverging results, so it's hard to know really where you stand. I come out as way below average for Americans on the Al Gore site (again, doesn't include consumption), about 45% of average at the EPA site (which, remember, doesn't include air travel); and 42% of  an average Californian's emissions on the Cool California site.