In the evaluation of climate change mitigation interventions a lot of questions revolve around the greenhouse gas (GHG) mitigation impact. Did the intervention actually reduce GHG emissions? And if yes: Who can claim that his actions were the cause for that? What a difficult question. For one, it is always hard to measure something that did not take place like the GHG emissions that were supposedly avoided. But beyond this conundrum, additional attribution issues are introduced through the indirect nature of many climate mitigation interventions.