> Telling the 3rd world they must stay poor because 'we already used up all the Co2 emissions' is not going to work.

Why not? To sell oil you need massive and fragile infrastructure in place: pipelines, storage tanks, terminals, etc. This infra can be easily controlled. As soon as world powers decide that the damage done to the planet outweighs economic effects of cheap energy, they can easily impose global limit on oil trade. Which can be enforced by both economic and military means.