I don't have a better suggestion, but emissions per Capita isn't necessarily fair. For instance adding another horrifically oppressed person can't mean that the

I don't have a better suggestion, but emissions per Capita isn't necessarily fair. For instance adding another horrifically oppressed person can't mean that the elite of that country "deserve" to be able to emit more CO2. It's somewhat less clear how that should extend to economic inequality, of how it should apply in individual real world cases, but it does seem a flaw of the model.