How many humans can fit on Earth?
It's not a logistical question (heel-toe, or nose-to-nose?). It's a question of resources. Every other species on the planet lives with a natural limitation. Say you're a snail that lives in a scummy pond and eats algae. There's plenty of algae available, and soon there are snails everywhere. But as your population booms, and you start bumping shoulders with other snails more often, you find there's not enough algae to go around. A lot of snails die or fail to reproduce. The algae population rebounds while the snail population fades, and the cycle continues.
Humans have beaten this system--for now. We clear forests, irrigate deserts, and blow the tops off of mountains to get the resources we need. This means we've stretched our upper limit. And according to a new report from the United Nations, there's no end in sight.
Previously, the UN ...
