Because we have a hard time sustaining. It's easy to laugh off the deniers instead of educate. Or just not care since it doesn't immediately impact me.
The more time that passes, the less real it is, the less people that can talk about being there, the easier it is to deny.
Maybe it's different if it's a disaster from something like a meteor. Slightly harder to deny that it happened, but certainly not hard to question and doubt the long term impacts.
'Sure, it had x and y immediate impact, but even though there's general consensus among experts that we should do z, let's go slow/let's not be too hasty/no one could be sure/what do they actually know/but there's these small group of opposing experts that I like better.'
The more time that passes, the less real it is, the less people that can talk about being there, the easier it is to deny.
Maybe it's different if it's a disaster from something like a meteor. Slightly harder to deny that it happened, but certainly not hard to question and doubt the long term impacts.
'Sure, it had x and y immediate impact, but even though there's general consensus among experts that we should do z, let's go slow/let's not be too hasty/no one could be sure/what do they actually know/but there's these small group of opposing experts that I like better.'