3 Calculating your carbon footprint

3.1 Getting prepared

You have already seen that there is no single way to define a carbon footprint, nor any consensus about what is best. In this section you will look at several freely available carbon footprint calculators. You may also want to consider how you would put one together yourself using (say) an Excel spreadsheet.

Not all of the sites in section 3.2 offer a disinterested estimate of your footprint. Some use the footprint calculator to offer to offset your emissions at the end of the process. Keep a note for each calculator you try (and there are far too many to try them all) of what data you were asked for, and how often they made assumptions about your lifestyle based on UK averages. You will note that most calculators work on driving distance, not actual fuel consumption, and not all adjust for differing sizes of engine or driving styles; some don't even include rail or bus travel as an option. Try comparing the results, especially for a common flight (such as London to New York) and then see if any assumptions are given that might explain differences, such as the effects of contrails or radiative forcing.

After you have worked through some of the calculators below, do you think that you could create a spreadsheet to do the calculation for you? Where would you need to go to get data on air travel distances?