Who carries the burden

Al Gore lays it out:

A new treaty will still have differentiated commitments, of course; countries will be asked to meet different requirements based upon their historical share or contribution to the problem and their relative ability to carry the burden of change. This precedent is well established in international law, and there is no other way to do it.

I don't know enough about international legal precedent to comment on that aspect of what he's saying. In a broad sense it seems to me that because of their outsize power, big contributors to international crises are often subject to milder, not stronger, dicta (nuclear weapons, territorial expansion, etc) whether those dicta are codified by law or not. But even if Gore happened to be wrong about the legal question--which I highly doubt--he's completely correct on both a moral and a practical level. Still, I find it hard to imagine that the United States and China and India are all going to voluntarily assent to this sort of corrective regime, and as powerful as they are, it's not clear to me how the rest of the world can convince them otherwise.