Since COP 21 in Paris, I keep thinking and thinking about what the critical first steps are towards achieving a carbon neutral economy. First, we need to immediately end all oil and gas subsidies. Second, we need to develop a transition strategy for leaving oil in the ground, the 'stranded assets'. And third, we need to begin to measure what counts, and in this video Mathis Wackernagel explains how to measure sustainable development. At the end, he asks some very provocative questions that we should all begin to ask of ourselves and our decision makers.