I think timescale is the important factor for spontaneous organization. As you noted with climate change, despite us feeling the effects of it every day, it's still "abstract" to many of us. That's a problem for later, we don't need to deal with it now. And even then, if you asked the average Joe if we should act immediately around climate change I think you'd find there's enough of us out there who are willing to do something. We just aren't sure what or how. We've been prevented from acting with self determination for most of our lives and the practice isn't familiar to us.

A quick aside, because I don't want to forget about your mention of cooperation in conflict. That impulse is still present and practiced in times of political strife and war. You see it all the time without realizing. People react in much the same way after a series of bombings that they do in natural disasters. I don't have any examples off the top of my head but it should be easy enough to dig up a few stories on the subject.

I was writing earlier about the importance of prefigurarion organization to build a successful stateless society. These practices not only put egalitarian power structures in place (neighborhood councils, unions/syndicates, co-ops) and forms the basis for direct distribution in a moneyless economy, it also allows individuals an opportunity to practice self determination, direct action, and exercising real political power. And that's part of my reasoning as to why I think time is a more important factor.

All of these things will be important as climate change progresses. As Peter Gelderloos highlights in his book "The Solutions are Already Here" (couldn't find a free copy, otherwise I'd link it) the state is incapable solving climate change. Many of their grand projects have been either unnecessary, inappropriate, or abject failures. Grassroots efforts have been far more successful and long lasting. The best thing the state can do for climate change is to get out of the way and allow people who know what they're doing to work.

People are able to act and react, but we're not permitted to meaningfully act in our day to day lives as a consequence of various forms of heirarchy. Have you ever had to stand by and watch something awful/dumb/misguided happen because the reaction from those with power over you may have been more severe than just letting the thing happen? Stuff like that is happening on a mass scale every day because those above us hold a monopoly on the legitimate use of force and are happy to use it if the "threat" you present is great enough.

I'd keep rambling but I have to get ready for work haha. Feel free to reply or DM me, I'm happy to talk!