The civil war in Syria started with a famine, which is certainly evidence for the claim. Culture preserves adaptation strategies long after those ideas become maladaptive.

But nature is bad enough. As a climatologist, what keeps me up at night is Bangladesh. A couple meters of sea level rise, and a direct hit from a super typhoon, and we could easily see millions of refugees. And as India continues its tilt towards a Hindu state, conflict could also happen there.

History is not a field where it's easy to make falsifiable claims (until we invent time machines). But I don't think that completely prevents us from learning something from the past.

It'll be as falsifiable as many other questions that historians grapple with (e.g. did famine X lead to conflict/instability Y?), but only once the warming has happened and we're looking retrospectively. The best we can do now is an educated guess that large amounts warming will lead to migration away from hotter countries which will lead to some instability.

The concept is equivalent to "Bring a coat, it might rain" not "It's going to rain"

We apply a different standard here, "Extraordinary claims require extraordinary evidence".

Isn’t that true of almost every field that deals with humans?

Health - coffee/alcohol is good for you this week and bad for you next week

Sociology and Psychology - is anything in these fields truly falsifiable?

History - same

Question: Is evolution falsifiable?