From ads in yesterday’s Guardian, I found myself at the carbon footprint estimator. This is obviously part of BP’s promotional campaign designed to make us think that a giant oil company couldn’t possibly be a big polluter.

That aside, it’s quite a useful toy. Apparently my household’s carbon footprint is around 7 tonnes of CO2, which is below the national average of 10 tonnes. Much of this is because of my air travel, which I try to offset via this sort of site.