It's pretty much the number one global issue right now, or at least should be. Unfortunately people focus on the here and now, so issues such as terrorism (which many in the West and other major countries will be completely untouched by) take priority instead since 'beating' ISIS is a better soundbite.
Part of me wonders whether the number of older politicians has some impact upon this. Irrespective of what they believe, I'd imagine any politician who's around 50-60+ doesn't need to worry too much about this because when the really disastrous effects kick in they'll be gone, leaving us to deal with the consequences.
At this point any country reneging on things like the Paris Agreement, or worsening the problem in a blatantly active way, should be treated in the same manner as any terrorist organisation would. This won't happen, of course, but Trump reneging on climate deals and undoing much of the global work done through trade wars etc would be far, far worse than anything done by...well, just about any group out there.