The question isn't whether or not this would work, or whether we would
continue to pollute afterwards. (Both good questions though).
The question is how we would make the decision to do this as a planet.

The innovation we need is not in the area of technology, but in decision
making.  Back before the endless-September, I think many of thought the
Internet, through some kind of authentication overlay to Usenet, would enable
well informed direct democracy.  Man we we were idealists.