try to figure out how much carbon offset you have in one month (and what causes it). And then make a nice infographic out of it. An idea from Bart

I like! I bet it would be surprising...

things like: how many energy does lighting and cooling in the supermarket use, how many people are visiting every day and what share of the energy is yours... i bet Albert Heijn is not with Greenchoice :)

true. and you can hardly avoid streetlights ;-)

that would be a massive research though...

well, maarten has a full month for it!
i wonder how many days leave he has available :)