Per captia doesn't matter.

> Then China could fracture into 10 separate nations, and their output would sudenly be negliable?

Don't you see the argument goes both ways? If the US merge with a few Africa countries, does it count as an "improvement" in regard of carbon emission?

> If the US merge with a few Africa countries, does it count as an "improvement" in regard of carbon emission?

Yes? I fail to see what your point is?

But seems both unworkable and likely to fail/lose its positive effect in less than a decade anyway.