With the CO2 calculator from the Nature Conservancy anyone can calculate how many tonnes of CO2 their lifestyle creates. For that, users need to enter some data, such as how many long-distance flights they take per year, whether they use energy-saving lamps, and what they eat every day. Based on this information, a user's personal CO2 value is calculated.
The interesting thing is that, with the aid of an average, a user's CO2 footprint is put in context and they can better assess how damaging to the environment their lifestyle really is. Naturally, we tried it out: the footprint of this case's author is 9.5 tonnes. This is almost twice the global average, but definitely lower than the per-capita emissions in the USA.
Whoever wants to ease their guilty conscience soon receives the opportunity to donate to the Nature Conservancy. The donation amount is dependent upon the person's CO2 output. Clever!