Toby Ord's book The Precipice does a good job evaluating them. Top contenders are AI, bioengineered viruses, nuclear war, and climate change, with natural disas

Toby Ord's book The Precipice does a good job evaluating them. Top contenders are AI, bioengineered viruses, nuclear war, and climate change, with natural disasters that we fail to avert/mitigate, like asteroid impact or supervolcano eruption as a distant aslo-ran.