Tough argument to make. Nation states are a somewhat arbitrary construct. What if China or India were each four countries instead of one? Should we take geographical area into account? This is why the per capita measure is important. The UAE is land mass less than 2% the size of India and China and relies on desalination plants for habitibillity. Why would either India or China have populations that small, while not having such limitations? It's easy to say less humans is the solution (and don't worry, the world is clearly headed that direction looking at global fertility rates) but saying a specific country having less people is part of the solution, especially when it's a country with lower per capita emissions, seems difficult to justify.