> It's not wealth and population, it's the use of fossil fuels It's all three. Our formula was emissions = (GDP/capita)(emissions/GDP)(pop). Reduce any of the

> It's not wealth and population, it's the use of fossil fuels It's all three. Our formula was emissions = (GDP/capita)(emissions/GDP)(pop). Reduce any of the three factors and emissions drop. Your phrasing is off. You can't say "it's not factors 1 and 3, it's factor 2" as that implies factors 1 and 3 don't affect emissions. We could choose to focus our efforts on (emissions/GDP). That doesn't mean the other two factors don't affect it. Reducing human population 10x would have the same effect on emissions as improving our (emissions/GDP) 10x. Spending $10k/year instead of $100k/year will almost certainly reduce your carbon footprint. France and China are a good example of why the other two factors might be important. Looking at their wealth (GDP/capita (PPP)) and emissions, we find that France is about 4x more efficient in emissions/GDP. But France is one of the top countries in emissions/GDP and China is one of the worst. If we assume the whole world becomes as efficient as France in emissions/GDP and the population increases to 10 billion and the world average GDP/capita increases to match the US (~3.6x increase), we end up with about 1.2x our current emissions. So you could focus all your efforts on trying to make the whole world much more efficient than France in emissions/GDP, or you could look at the trade offs between all 3 factors and try to reason about how we'd like to balance those factors.