You've made a great point - if we've really reached a tipping point at some of the more extreme global warming alarmists, you wouldn't spend any money at all. So they've inadvertently caused logical people to decide we shouldn't do anything.
The other end of the spectrum would try to convince you that global warming isn't real (global warming and cooling has happened for eons - without man's help) and that it's therefore not worth doing anything.
As an ecologist, I drive my wife and kids nuts with my need to recycle ... and take it a step beyond. I've repaired all sorts of "throw-away" household gadgets (most recently my wife's straightening iron) and try to give away working items we no longer need (freecycle). So I still believe we should each do what we can to minimize our impact on the planet, whether or not global warming is real.
Maybe you'd have to spend twice as much to have the desired effect.