Unanimous on the part of almost 200 nations, this weekend's "Paris agreement" is being hailed as "historic" — even though there's no way to enforce promised reductions of greenhouse emissions. Public disclosure is required every five years, with the prospect of "naming and shaming" countries that don't meet their commitments. It's also being called a "signal to investors" that the "age of fossil fuels" is ending. That's aimed at Republican US Senators and other climate deniers. Will the international marketplace supply the enforcement mechanism that diplomacy failed to provide?