Huge regions have burned, flooded, fallen into the ocean, or been destroyed by hurricanes in "once in 100 years" events.

The predictions were never that the whole world would be affected at once. They said that "impossible" and "rare" disasters would become commonplace and resources would become scarce. Those things have happened.

Climate change compounds with ecosystem destruction compounds with species mass extinction compounds with ocean acidification:

And something in the "web" of species interdependence breaks and we get a total collapse of the biosphere in some functional way. Something like "no more crops will grow".

Or more ominously: oxygen-generating microorganisms in the sea go extinct.

This stuff is on the table.

Because all climate variation in previous generations occurred within a timeframe that evolution could adapt to, and without barriers to species migrating to new zones as they moved. Humans are destroying species and changing ecosystems faster than evolutionary adaptation can adapt to, probably by several orders of magnitude.

Fundamentally, modern human civilization is playing russian roulette with itself.

But I fully agree that scaremongering doesn't help. Evidently: with COVID gone roads are more crowded than ever, air traffic on pre pandemic levels, no less meat consumption.

It's not that no one is scared, is just that most people don't know how to change.