There is overwhelming consensus in the scientific community that AGW is real and is a cause for grave concern.But there is as yet, no one world government, and no consensus on AGW claims, you are speculating about the future and imho, you are on the wrong side of history, the baddies days are numbered.
You do not need a world govt. Corporates and Govts. who do not pay reparations for damage will be stopped from trade and doing business. Of course all of this will happen only if we do not do anything voluntarily now. The climate damages will rise exponentially to the point where unregulated emitters will be treated like North Korea's Nuclear weapons program. Pariah states and pariah companies.
You are on the wrong side of history, not me.