If per capita means nothing, the logical solution for China is to split itself into 100 countries. Somehow that would make the contribution from each new country less important in your view.

Measuring by per capita pollution and getting that measure down is the only sane way to count emissions. The end product is the same, total emissions go down, but we can focus on a metric that makes sense no matter how large the country you’re measuring is.

We don't generate emissions for the fun of it, we do it to support the lifestyles of humans.

Sure, total emissions is what matters, but the formula for total emissions is:

    Total Emissions = Emissions per capita * People

Unless you're proposing a reduction in people (don't) then per capita means quite a lot.