So it makes me think the alarmism is simply political performance.

I very much agree with you that the discussion in the west is largely performative. We can see it with stuff like tariffs on Chinese EVs, solar panels, and so on as well. Clearly western governments see economic warfare as being more important than addressing the climate crisis. We also see resistance towards practical solutions like nuclear power. Germany is a perfect example where they dismantled nuclear industry and now use coal instead. The fact that China is pushing the transition without the panic is a strong indicator that they believe that it's possible to navigate the crisis without our civilization collapsing.

It is worth noting though that even though life has navigated many challenges, extinctions do happen. And life forms absolutely can bring about their own demise as seen with the Great Oxidation Event. If our activity is changing the climate at a rate that complex organisms aren't able to adapt to, then we could trigger an extinction event as well. It's going to be little consolation to us that life will continue on in a different form afterwards.

That said, you are absolutely correct that the west is using the climate crisis as a political vehicle to justify why the rest of the world can't develop the way the west did. This very much needs to be called out. What we really should be saying is that the west carries the most responsibility for the crisis historically, and people living in the west are consuming disproportionate amount of energy today. So, the west needs to own majority of the responsibility.

Regarding the paper, I think there is some evidence that AMOC collapse could happen, and it will be bad news for Europe. That, of course, doesn't mean the paper isn't politically motivated.