The entire species is designed to deal with 'far off' threats and ignore them. Think of any animal, let's take a squirrel. It has to be afraid of cats, canines, bird of prey, and at the same time leave the burrow every day, and all day long look for food.
If the predator is not breathing down your neck? You are watchful but ignore it.
Similarly, our ancestors and ourselves? We are social animals. We live in a pack. We share defense with our tribe. You and your neighbour will stand back to back, to fight off barbarians. Meanwhile, in parallel, we need to defend ourselves from members of our tribe. The very person who fights back to back with you, to save your community, may be your tribal competitor. Whether for dominance or breeding, we fight amongst ourselves. We know there is risk of our neighbour, our fellow community member attacking and killing us, meanwhile? We lay our head down and sleep.
We're designed to take low probability threats, and cast them off, and nothing is more low-probability than 'it will happen in the mysterious future'.
Global warming is as 'far off' thing. You may say "But this and this is happening!", and I agree! But I still live in my house, I still have grass and trees, I still have food, and so for most people "far off in the mysterious future" is a valid response.
If you can't see the enemy before you, it is easy to shrug away. If you cannot see the threat as impending, it is easy to ignore.
It's in our very nature. It's a requirement to sleep soundly at night.
At least, this is my take on 'far off' threats.