They essentially say that (better) international cooperation is required, and must be functional at the required (global) scale... and the other paragraph essentially cautions that "some might find it easier to take from neighbours", leading to war, which is a proven and terrible waste of nearly all resources.

I would note that while we don't have a global society, we do have a global information space (enabling different actors to understand the same data and to see a mutual failure as the end of certain actions, even if their viewpoint differs) - and we do have global trade. Arrangements where an economy making a transiton off fossil fuels, for example, enacts carbon use limits locally and simultaneously taxes carbon-intensive imports across its borders, would remove the biggest dis-incentive to transitioning - that of getting things cheaper by polluting somewhere else.