Fear and panic are not the same thing. If your car is rolling towards the rim of the grand canyon and isn't slowing down, you would be afraid but ideally would quickly but calmly consider and try your options (emergency brake, steer away from edge, bail before it reaches edge, etc) rather than panicking.

What if you are the passenger and the driver has their foot down on the accelerator while refusing to believe that the cliff lies ahead? What is the appropriate emotion?

Still composure, and the appropriate course of action is still to evaluate your options and choose the best one, even if that's the best option out of a list of bad options.

Unless you think that panic will induce the driver to stop accelerating, I suppose. Though I think the closer analogy would be "you're a passenger in a car with a brick on the accelerator and no driver", because I don't think there's any person or coherent group of people who actually control the global economy (in the sense of "control" where they can make sweeping changes that go against local incentive gradients, and have those changes stick).

If doom is certain, then what does your composure or anything else matter?

If nothing matters, in what sense is panic the "correct" response?

Also, it's useful to check whether you're absolutely doomed to lose everything you value, or only probably doomed to lose most of the things that you value, in situations where you appear to be doomed.

I don't think a panic response is generally helpful towards the goal of "make the best you can of a bad situation".

your chances of survival increase if you're not panicking.

This is well understood by everyone and only needs to be said because you feel the need to ask 20 questions in an attempt to imply there's a fault to the thinking (because you can't outright say it or the jig would be up).

This is a wrong take for various reasons. Panic is a response we developed for survival against predators and clear-and-present dangers. But look around, the only predator in sight is us. Can we panic against ouselves? Climate change and more general sustainability is above all a collective social/economic and political organization problem.

How we internalize and communicate about the predicament we brought ouselves into is important. You don't cry fire in the crowded room you find ways to calmly evacuate.

Which brings to the second reason panic is hopeless: It is also objectively not possible for us to "flee" in a hurry (Except for Elon and his Mars escapists - good ridance). The crowded room is our planet and there is nowhere to go. We are doomed to "work it out", put down the fire. We have no option but accept the damage that will be inflicted in the mean time. The smarter and faster we "work it out", the less damage. Thats the equation and tradeof.

But nobody ever solved a tough problem in a state of panic.