Yes, the non-efforts of some (typically second-world) countries do (or would) undercut the true efforts of those who care to try. But it makes me crazy to hear the argument that we in the first world should do nothing unless we can get everybody to help.

This crazy argument is like a crowd watching someone drown. Unless everybody helps, nobody should.

We can't do anything about an asteroid strike. We can do something about climate change.

Back to our drowning victim. People get hit by buses. He might get hit by a bus next week, so perhaps we should just let him drown.

I don't know if OG is a scientist of any type, but the overwhelming scientific consenus is that we are plenty far enough into it to know that it is real, and that human activites are contributing to some degree. We can still argue over the degree.