The world isn’t just the USA and Europe, and their proclamations aren’t the law of the world nor are they the world police. Nor do the majority of the Earth’s emissions come from developed countries.
Go ask some people in developing countries if they think they should sacrifice economic growth for climate change. The answer is going to be overwhelmingly no. The developing world also has the majority of the world’s population, so the global consensus actually belongs to them, not us.
I think what you'll find is if all the developed nations believe their very existence is at stake due to actions of the un-developed, it will result in war/the end of the threat very quickly.
Case in point: the fabricated idea that Iraq had chemical weapons that could hit western Europe. There wasn't a lot of debate on whether or not the western world was willing to eliminate the threat if it existed.
(note, I'm not trying to turn this into a discussion of the fabricated information, simply using it as an example that war is always on the table if a country feels its existence is in danger).
Go ask some people in developing countries if they think they should sacrifice economic growth for climate change. The answer is going to be overwhelmingly no. The developing world also has the majority of the world’s population, so the global consensus actually belongs to them, not us.