Well, if they're old enough then they probably either experienced first-hand (or heard first-hand accounts from even older folks) the relative cold of the 1970s

Well, if they're old enough then they probably either experienced first-hand (or heard first-hand accounts from even older folks) the relative cold of the 1970s, which was preceded by the relative heat of the 1930s, which was of course itself preceded by a relatively cool period. So there is a definite down/up/down/up cyclical nature there. And current flooding issues are generally nothing like what occurred before effective flood-control measures were put into place. And current forest fires are generally nothing like what occurred before effective fire-control methods were put into place. Being young, you've grown up in a fairly "controlled" world, so (much like anti-vax folks who don't understand what the world was like before vaccines came along), you have no life experience dealing with the world as it existed before those other controls were put into place.