Everyone and even their dogs are offering carbon footprint calculators these days. This is generally a good thing, whomever wants to be a Green Hero needs to know their footprint or at least a ball-park number. However, we did a simple experiment to calculate two simple footprints across several calculators and we were quite surprised by the result. Why? You would expect to have quite similar footprint if you flew a standard commercial return flight from London to New York, economy class. Or if you drove 10 000 km in an average diesel car right? Not.
Here are the comparison numbers we got – you be the judge.
Surely, some of the differences are explained by use of different inputs and sources, but seriously – deviations of 2-3x do not look credible for a common person who simply wants to offset her footprint.