The Population Bomb by Paul Elrich back in 1968 predicted worldwide famine in the 70s and 80s because of overpopulation. There's been quite a few over the last few decades relating to overpopulation, environmental destruction and running out of vital resources to keep civilization going. So far, these dire predictions have not come true. Which doesn't men they can't, but they should give us some pause about predicting the collapse of civilization or the environment, particularly in the short run.
There has always been a market for mass-market doomsday prediction material; whether religious or secular.
A population bomb leading to famine has never been the result of prolonged scientific discussion, just one guy's theories (published in book form, which is subject to editorial review but not peer review), and saying "this is a prediction that someone made that was false" is true but unhelpful. Anyone can make a prediction, and a lot of dumb stuff gets published. Never made it meaningful or true.
My father, before he succumbed to dementia, had this belief that if it's been published, it must be true. He'd read the weirdest stuff and ultimately decided that nothing is true; when really, it's because he was overly credulous at first, and in rejecting truth as a concept, he went too far the other way.
I feel like that's a lot more common than we realize; the error is not in believing in a consensus reality, it's in believing in something that wasn't very good to begin with (a book about worldwide famine, the handful of "global cooling" articles in the 70s -- not even a book! just a handful of magazine articles!! why would ANYONE put stock in that??), and deciding that, because that was wrong, nothing is knowable.
It's not that nothing is knowable, it's that predicting the future is hard and easy to get wrong, particularly with something as complex as civilization, since humans adapt and civilization changes. The same applies to the biosphere as well. Saying for example that polar bears will go extinct or coral will all die off is ignoring the possibility that some bears and coral will adapt to the warmer world. We can't be sure about such predictions. We need to see how life and civilization responds.
Usually the life responds by getting extinct, as seen in so many species lately. What makes you think humans are special? Do you expect speciation for a change that will take less than 100 years?
Technological evolution on an unprecedented scale?
Because this is what it is going to take. Not even going underground en masse will work and that is essentially the most extreme social change I can see. (Even more extreme than space travel, cars, internet.)
> Usually the life responds by getting extinct, as seen in so many species lately.
Do you have a count of how many have gone extinct in the past decade?
> What makes you think humans are special?
Our brains. And yes, technology and science. Humans are extremely adaptable. Our ancestors survived an ice age with stone aged tech and spread around the world to live in all sorts of environments.
> Not even going underground en masse will work
LOL, what? Who is saying that the Earth will become so hot that we won't be able to survive on the surface? You think 3-4°C is going to have that effect?