While peace and global unity are laudable pursuits (on the surface), such goals ought to be seen in the light of what took place at the Tower of Babel (Gen 11:1-9). This event stands as a stark warning against utopianism, against man's proud and unending use of politics, economics and false religion to attain global unity apart from God. Mankind's ability to fashion such a world was forfeited at the fall and until we return to our Creator, and embrace His appointed means to reach this goal, mankind's quest for global unity will inevitably end in chaos and utter destruction.
According to Scripture, mankind will indeed finally succeed in creating this global counterfeit kingdom (Rev 13:8, 16:9, 17:8) but God will overthrow it, bring judgment on the earth, and join the family of man together under his righteous rule and bring in the only true lasting kingdom. (Rev 21)
"And whereas thou sawest iron mixed with miry clay, they shall mingle themselves with the seed of men: but they shall not cleave one to another, even as iron is not mixed with clay.
And in the days of these kings shall the God of heaven set up a kingdom, which shall never be destroyed: and the kingdom shall not be left to other people, but it shall break in pieces and consume all these kingdoms, and it shall stand for ever." Dan 2:43- 44
Note: I believe this same truth can be applied to just about any situation where human beings are endeavoring to do good. When God and the gospel are removed from our charity, and we chose to do things our own way, we set up a counterfeit which does no ultimate good to the parties involved.