The obvious answer is fossil fuels, right? Few people want to cook the climate, they just can’t quite fathom something that abstract and slow-moving, so they do it anyway.
Less obviously, feeding all our most sensitive data to random websites and apps. Again, the threat just doesn’t look enough like a sabre-tooth tiger.
No, it’s not that people are unaware, or even don’t believe it, it’s that they can’t reason about it strategically
It’s spending now to save later. If that’s about military spending or emergency services everyone gets paying taxes for it, but words are as far as most will go to stop nonspecific far future weather. Even when people talk about the situation with climate change, you hear them frame it in moral terms instead of practical terms.
Case in point: Canada has a carbon tax, and a majority want to get rid of it. Denialism is not a prominent part of the campaign, just the fact that it costs something. And not even much, and it’s all given back in refunds - doesn’t matter, the extra gas cost people will bear is zero.