Why should should per-capita be most important? If country A keeps their population stable and emissions under control, but country B of the same starting population, keeps doubling their population and doubling their emissions, why should country A have an increasingly declined allowance of emissions when they were more responsible in keeping their total emissions down (by not having as many people)?

Because per capita is the only thing that makes sense.

If China were to split into 10 countries each emitting 10% of what they do now it'd be the exact same emissions, but according to you it would be much better.

Similarly if the EU would become one country, that country would be high up on the list, much higher than member countries now! Oh no!

Looking at per capita emissions is much more fair.

Anyway, China's emissions are falling since last year ( https://www.carbonbrief.org/analysis-chinas-co2-emissions-ha... ). What's the US doing?

If country B splits into countries C, D, E and F, all of which emit less than country A, has it found an effective way to reduce emissions? Should all countries adopt the Monaco lifestyle to defeat global warming? I guess if you want to find a fair way to measure administration of land you could emmisions per hectare or rainfall.

China has a declining population, and had a one-child policy for many years.

Also, you don’t want all the low-population countries to each start contributing as much to global warming as the US.

Because some countries pay others to pollute in their stead?

Because country A just outsourced their emission production to country B.