Humans were around for the ice age, but not any of the humans I know. That was about 4 degrees Celsius, right? Over thousands of years. Meanwhile, my mom has lived through about 1.5 already and will probably see 2 in her life. Hell, depending on the breaks, I might live to see 3. Compressing a geological age into a human lifetime is bound to have some wacky effects. I can’t imagine being a kid today and thinking how much they’ll live to see.