An Uncertain Future
Climate change is fundamentally a future-regarding phenomenon. The actions that we take today will have impacts some 20, 30, 50 or 100 years in the future. In some cases, those impacts will occur much, much further in the future. Naturally, then, one might want to argue that because of this, we ought to be concerned about how that future will look. One complication? We simply can't say with any certainty.
The Epistemic Landscape
The first problem we face when we're talking about the future is that we simply don't know how the future will turn out.
What this all boils down to, then, is the problem of uncertainty -- or, at least, what many people think is the problem of uncertainty. In the policy arena, there is a vast body of literature on decision-making under uncertainty. In fact, a whole
Here's a really nice discussion of decision-making under uncertainty as it relates to climate change: