[Kon5ole]

>The Montreal Protocol to reduce CFCs in response to the hole in the ozone layer is a perfect example of us doing this.

I can't agree with this, the efforts are several orders of magnitude different. Sure humans worldwide can cooperate on small things and do so regularly. The olympic games spring to mind. Or the ISS.

The Montreal protocol was great, don't get me wrong, but it basically boils down to "Hey you couple of hundred thousand people in a small part of industry, please use chemical Y instead of chemical X. Otherwise carry on."

The effort required to stop global warming is entirely different. It will affect billions of people, entire industries will be terminated permanently, millions will be unemployed, rich countries will suddenly be poor, global trade will grind to a halt.

And we can't even be sure that effort will actually work.