I think it's the confluence of three major trends that are all going to hit concurrently, within the 2020s. Global warming, as you mentioned, which is going to

I think it's the confluence of three major trends that are all going to hit concurrently, within the 2020s. Global warming, as you mentioned, which is going to cause widespread droughts and crop failures, a redistribution of habitable land, mass migrations, and increased frequency of natural disasters. A demographic bulge that is all hitting prime young adult & family formation age right now. Historically, societies get more violent when there is an excess of young unmarried men with poor prospects for finding a mate or raising a family. And this is exacerbated by... Systems and institutions that have become rigid, complex, and too inflexible to change. The rational response to a large number of young adults reaching family-formation age is to build more housing. Zoning laws prevent that. The next best response is for all these young people to move to new cities and settle new land, building their own housing. You can't do this when all the land is already owned, and you need a job to have any hope of getting enough money to buy it. That forces all the people to cluster where the good jobs are, but the good jobs don't want to leave areas where skilled workers already are, and those are the same areas with a shortage of housing. Perhaps the reason people are acting like the party is going to stop soon is because they're right. People aren't stupid; even if they haven't studied enough history to rationally analyze it, they emotionally know that something's wrong. When you switch from an abundance to a scarcity mentality, the rational response is to grab whatever you can personally, because by definition, there isn't enough to go around. And unfortunately this results in chaotic behavior that is very difficult to plan around. It'll be a great time to build long-term things after the crisis reaches a climax and everybody who's going to die and every institution that's going to fail already has. Until then, the priority is surviving to that point.