catastrophist

Of, having, or being a theory that explains a situation by positing one or more catastrophic events, as opposed to gradual changes.

But there is an incredible disconnect between what tourists see, what foreigners living in France see, what French people living abroad see, what this recently naturalised français sees, and the hyperbolic, catastrophist nature of France’s own domestic discourse about itself (that is, the French people convinced their country has gone to hell).

A catastrophist person: a person who subscribes to a catastrophist theory.