In the general rush to downplay "Towards Reforming the International Financial and Monetary Systems in the Context of Global Public Authority," I haven't seen mention yet of the document's final paragraphs:
Through the account of the Tower of Babel (Genesis 11:1-9), the Bible warns us how the "diversity" of peoples can turn into a vehicle for selfishness and an instrument of division. In humanity there is a real risk that peoples will end up not understanding each other and that cultural diversities will lead to irremediable oppositions. The image of the Tower of Babel also warns us that we must avoid a "unity" that is only apparent, where selfishness and divisions endure because the foundations of the society are not stable. In both cases, Babel is the image of what peoples and individuals can become when they do not recognize their intrinsic transcendent dignity and brotherhood.
The spirit of Babel is the antithesis of the Spirit of Pentecost (Acts 2:1-12), of God's design for the whole of humanity: that is, unity in truth. Only a spirit of concord that rises above divisions and conflicts will allow humanity to be authentically one family and to conceive of a new world with the creation of a world public Authority at the service of the common good.
I found the first paragraph a bit odd, since of course God directly caused the diversity of languages at Babel, in order to keep mankind from never "leav[ing] off from their designs, till they accomplish them in deed" (Gen 11:6). To me, this is less a warning of the risks of diversity than a natural consequence which the LORD took advantage of to keep mankind from getting too big for its britches. Surely the failure of the plan to build a tower the top whereof may reach to heaven was not a bad thing.
Which is not to deny that the story of Babel is instructive when considering the context of global public authority. In the second paragraph quoted above, the true foundation of global unity is rightly said to be found in the events of Pentecost, a Divinely-caused inversion of the events at Babel. And what is that true foundation of global unity, that "unity in truth"?
"And it shall come to pass, that whosoever shall call upon the name of the Lord, shall be saved." (Acts 2:21)
The Spirit of Pentecost, thought, was not a spirit of mere concord. "There can be concord in evil between wicked men," as St. Thomas observes -- and, if I'm not mistaken, as the account of the Tower of Babel illustrates. (Whether the account of the ongoing economic troubles illustrates the same principle I leave to others.)
So I would say that the story of Babel not only warns us that we are bound to lack concord if we don't speak the same language, but -- reading it in parallel with the story of Pentecost -- that the concord upon which any global authority must be founded to thrive in virtue is nothing less than the peace of Jesus Christ.
As a practical matter, the world is some way away from establishing that foundation. Whether Christians possess the peace of Jesus Christ in sufficient fullness to serve as the cement which, when mixed with the world's crushed stone, can form a concrete of sufficient strength to bear the weight of the Pontifical Council for Justice and Peace's proposals is, I suppose, open to question.