So let's say that there's a *descriptive* account of climate change (here's how things are changing) and there's a *prescriptive* account of what we should do about it (fight it like it's an emergency, plus use this situation to fix society). The descriptive part has real predictive power. So far so good.
And furthermore this changes the value proposition for joining the coalition. Now if you're a person who *merely* wants to fight climate change, you face a two-sided front against people who want the status quo as well as people who want social transformation welded to climate change. This is not an attractive proposition in part because it is not likely to succeed. The people who make bigger demands have a lot of prescriptive force, especially among bleeding-hearts, and...
The "mere climate" fraction of the coalition -- that is, those who are treating climate change as an emergency sufficient that they must forestall the social transformation -- are probably not going to persuasively prevail within their coalition because they do not have as many prescriptive references to deploy ("look at the suffering of X! don't you care?") and furthermore they are incredibly unlikely to succeed at the object level (actually fighting climate change) as a hyper-minority.
Now I want to admit that I could be wrong about the internal coalitional politics of people fighting climate change. It may be that "bleeding hearts" are less influential than I believe. And it may be that the "mere climate" faction is going to lead the charge. I hope they do. But I sincerely doubt it.
But the prescriptive part only has power if it brings together coalitions of people see the value in making it a reality. I think that more people see the value in fighting climate change than see the value in linking climate change to fixing society, and the mismatch between the two constituencies is going to divide the "fix climate change" coalition