Water

The same amount of fresh water we had when we were less, is what we have now when we are more. Law of conservation of mass. As it is, water was not here after the Earth was formed, many meteorites later it was accumulated. Then the water cycle began, going up and down, salty and icy, on land in rivers and lakes, on and on, and on.

Something has to give. Either fusion or fission reactors, or new ways to make more fresh water. At the end of the day we have to come to those odious words of the sixties, "limits to growth". Maybe we are too smart for that, and we will find a way, but by listening to the presidential debates, I am not too hopeful. At least I live near the Great Lakes, maybe that will be more important in the long term.