> How do you convince someone who utilizes NH's cold weather recreational activities (ice fishing, snowmobiling, skiing, etc.) to become more concerned about the shifting climate?

I think your entire premise is wrong. Unless I misunderstand, you're suggesting that you can appeal to them based on their selfishness, however none of the proposed actions are predicted to lower temperatures, only slow the rise in temperature. Certainly this is true of any effects of the proposals within the lifetime of the person you'd be speaking with today.

So why would it matter to them? You're appealing to their selfishness and then asking them to accept changes that won't benefit them which I don't think would work very well.

Analogy: imagine trying to get the patient recently diagnosed with untreatable, un-operable stage IV lung cancer to stop smoking. Why would they? The damage is done, their fate is sealed, and quitting smoking would only take away from what little pleasure they have left.