Not really following your point. Mine (and maybe yours) is that if people don't believe in the cause of the warming they won't fight it accordingly. Especially if that fight means their standard of living has to be sacrificed to some degree.
We disagree about human nature. I think most people are more motivated to make sacrifices, in opposition to a common enemy. Compared to admitting they're part of the problem and should cut back.
By analogy, consider the gap between rich and poor. This is absolutely terrible for the poor, even if they're only relatively poor. It makes them feel like shit when they work 50 hours a week or more, and still can't put good food on their family's table. "Good" of course being relative, but can you blame them for comparing themselves to the rich? Their work is undervalued, and that makes them feel undervalued.
Now this problem could be easily solved, by the rich. But do the rich give away their money to solve the problem? Do they in your words "sacrifice their standard of living"? No of course not. There is no external enemy causing them to take the side of the poor. Their attitude to the poor is at best, one of benign neglect. "Your problem buddy."
Globally, there is a strong correlation between poverty and being victims of climate change. The global rich can move to currently cold areas, or even to polar areas if shit gets real bad. The poor are stuck in the tropics, where monsoons may collapse, rain fall on deserts where it will achieve nothing without artificial fertilizers, new deserts made of formerly forested or agrarian land. Tropical diseases will increase.
If the rich won't take responsibility for poverty
in their own countries, what makes you think the global rich will take responsibility for starvation and disease in parts of the world they already regard as "shitholes"? They will blame anyone, and everyone, before they blame themselves.