Good question, and I'm not sure there's a simple answer. My guess is that initially we just have to be supportive of government putting their "thumb on the scale" (recognizing that there are many, many thumbs already all over the scale) to attempt to internalize these long range external costs. With climate change, some kind of forward looking pricing for carbon and other GHGs priced into actions today would be a start.
I certainly would try to avoid a simplistic binary argument such as that. Issues like these are on a continuum. There is no "side." That kind of thinking leans heavily on heuristic, which is often the path to being wrong. I am merely pointing out that in order to exercise the extent of the free will we have, we need to understand the consequences in a more immediate fashion. And that the market is not equipped to handle this, just as human nature is not. I'm not breaking new ground here, just repeating what has been discovered in behavioral economics over the last 50 years.