It just boggles my mind that anyone could be so naive as to think emissions can be curbed significantly, in a relevant time frame, by multilateral international agreement.
No one believes that emissions can actually be curbed, but no one cares because no one (or hardly anyone) is actually interested in solving the problem. They are far more interested in using the problem as a justification for controlling other people, in exactly the same way that anti-abortion crusaders don't care about reducing unwanted pregnancy and anti-drug crusaders don't care about reducing drug addiction (not use, addiction and abuse... you know, the things that actually cause the vast majority of drug-related problems.)
We know that prohibitionists of all kinds don't care about the problems they claim to be solving, because prohibition is always a lousy solution. We've known that about drugs for decades. We've known abstinence-only sex education and restricting access to contraceptives increases teen pregnancy. But the people who advocate those things don't care about teen pregnancy: they care about controlling people. Same with drug warriors.
And it's the same with abstinence-only GHG opponents. If they cared about the problem they would be massively pro-nuclear (some are) and more than willing to explore geo-engineering possibilities, however unlikely.
Think about it: there is a class of person who claims that anthoropogenic climate change is likely to produce a civilization-ending event, but are adamantly opposed to even researching any potential solution that doesn't fit into their bizarrely Puritan moral universe.