The contrarian throwaway said: "A significant, geologically fast rise in global temperatures would kill millions/billions of people, inundate coastal areas, result in major migrations and resource wars, etc."
-- this sounds close enough to what I said, simply "We all die." I didn't say the oceans would evaporate. But with that amount of damage, global civilization and culture would probably not survive. Going carbon-neutral is not a "meh, let's do it later, or not" type of thing.