Whether we accept it or not, this will likely be the century that determines what the optimal human population is for our planet. It will come about in one of two ways: Either we decide to manage our own numbers, to avoid a collision of every line on civilization's graph - or nature will do it for us, in the form of famines, thirst, climate chaos, crashing ecosystems, opportunistic disease, and wars over dwindling resources that finally cut us down to size.
The lesson of every extinction, says the Smithsonian’s Doug Erwin, is that we can’t predict what the world will be 5 million years later by looking at the survivors."There will be plenty of surprises. Let’s face it: who would’ve predicted the existence of turtles? Who would ever have imagined that an organism would essentially turn itself inside out, pulling its shoulder girdle inside its ribs to form a carapace? If turtles didn’t exist, no vertebrate biologist would’ve suggested that anything would do that: he’d have been laughed out of town. The only real prediction you can make is that life will go on. And that it will be interesting.