[throwaway5752]

My dire warning is in fact secondary to the climate changes, which are much worse and are already causing regional famines and human migration in the Levant and East African.

People do not appreciate how fragile modern life that we've become accustomed to can be. A few famines, a few supply chain breakdowns, the wrong conflict escalations - together at the wrong time could effectively end homo sapiens as an advanced intelligent species. Our big break was easily accessibly surface hydrocarbons, which we have mostly burned through. That enabled advanced materials science, electrical engineering, metallurgy that all build upon each other. As the species has gotten larger, it allowed greater specialization. If we have a massive drawdown in population as the result of a self-inflicted climate crisis, there is a nontrivial possibility we we never recover to current levels of advancement.