I wonder if the shortness of my comment made people think it was some sort of snark rather than a legitimate question.

My understanding is that the experts are predicting irreparable harm to many ecosystems if action isn't taken soon (already? http://en.wikipedia.org/wiki/Avoiding_dangerous_climate_change). It seems to me that by the time policy-makers decide to take some of those interventions, it may be too late.

FOLLOWING YOUR EXAMPLE: Just because we've done SOME irreparable damage doesn't mean we should just heap on more. You don't junk your car after getting into a fender bender.