People cooperate fantastically when there is economic gain to be had. We're fucking atrocious at cooperating if one (or both) sides are set to lose out (as is the case wrt reduced consumption).
Cooperating when all/most parties are better off isn't impressive.
Real cooperation would be something like the Saudis announcing over night that "you know what, climate change sucks so we're going to stop pulling oil out of the desert regardless of how much it hurts us".
How likely is that?
At the root of the issue is the fact that since humans aren’t able to measure the damage and see all the knock on effects of their actions, many large scale environmental and societal costs are externalized. And if you don’t take advantage of that, then someone else will and win in the market with lower prices.
In theory. But in reality the bigger challenge is to actually work together as humanity for a common goal. And given our history the current amount of cooperation is allready impressive - so it might be a good challenge to unite humanity in general. I am quite optimistic in the long run.
I mean, the internet is barely 20 years old for the common people ... it just takes time to grow together, when we have a history (and probably genetic heritage) of caring only about the immediate things around us. And the more drastic the droughts etc. get ... the more people see it as a problem and act. And yes, the great barrier riff and the polar bears might die out, but there are worse things, that can and probably will also happen. But we as humanity will survive, maybe on a slightly different planet, though.
So I don't think it makes sense to fall into depression, when the expectations were simply unrealistic.
I mean, sure, I would like to stop coal and fracking rather tomorrow and get power from solar plants in the desert ... but we simply are not there yet, as the challenge is big and not only technically.