It's a typical human short-sightedness/availability heuristic. People can act if you shove the consequences directly into their faces. All it took is two planes crashing into skyscrapers to start two wars and reinvent both transportation and information security (for better or worse). But the climate change goes too slow, you can't really see the consequences, you need to trust the specialists, and that's where things fall down. Doubly so if you have democracy, since you can't really do anything important if you keep asking everyone for opinion.