One World Governance and institutions such as the U.N. and the Paris Accord are relatively new ideas: Thank you Immanuel Kant.

FYI: One of the earliest philosophers to believe the idea that world peace was possible via universal democracy and international cooperation was Immanuel Kant, back in the late 1700's. Surprisingly, these  ideas are not that old.

 Kant did most of his writing at the end of the 1700's, just 200 years ago. "Universal democracy" is "one world governance," and "international cooperation" is the basis for the U.N., the Paris Accord, and other complicated forms of liberal silliness. All the pointee-heads out of our "best" universities are taught this nonsense, if they studied any form of "political theory." 

I studied Kant in college as it related to logic, morality and the foundational issues related to the concept of morality . This is when I first came in contact with what I believe is the most useless word in our language, "metaphysics." Course title was "Course study on the metaphysic of morality,"   as written by Kant in 1797.   They could have said "Foundational issues of morality," and it would have made more sense. Problem: "Foundational" allows for a divine notion of morality: "metaphysics" allows for the sequester of the God thingy.

Anyway, my point is this: Talk of the value of "one world governance" came into being around 1800, and the political landscape has rapidly changed because of this evolving theory.
Now you know.