Do we have good estimates of each country’s contribution to global warming?
How much could one country subvert the efforts of the rest of a unified world? Could, say, one industrialized nation, whether by its apathy or through deliberate overproduction and malfeasance, significantly reduce or even offset the combined effect of the others?
Depending on the answer, it would raise the question of whether military intervention against one or more global warming ‘offenders’, might one day be justifiable.
First of all, I’m going to rule that this part of the OP is more suitable to Great Debates rather than GQ. Let’s stick to the factual aspects of the OP.
Yes, there aregood estimates of the contribution of different countries to carbon and other emissions. China, by virtue of its population, and the US, by virtue of its large per-capita energy consumption, contribute almost as much carbon as the rest of the world combined. So energy policy in those two countries has a major impact.
You may want to ask about countries that subvert their own efforts. Example: China is currently trying to reduce carbon dioxide production at home by, for example, encouraging the use of electric vehicles, among other things. Yet its Belt and Road Initiative foreign policy encourages other countries to build coal-burning power plants.
