Experiments in setting individuals a carbon allowance have been trialled from Finland to Australia, and some have proved popular. But can carbon rationing ever be fair?

The goal of these experiments was to empower people to reduce their carbon footprint by giving them a better understanding of it. Even people who are trying to actively reduce their carbon footprint have very little idea of what their footprint is and where it comes from: is it electricity, is it petrol? Am I better off not driving, or making sure all my lights are off at home?