We have been engineering our environments to more productively serve human needs for tens of millennia. We cleared forests for grasslands and agriculture. We selected and bred plants and animals that were more nutritious, fertile and abundant. It took six times as much farmland to feed a single person 9,000 years ago, at the dawn of the Neolithic revolution, than it does today, even as almost all of us eat much richer diets. What the palaeoarcheological record strongly suggests is that carrying capacity is not fixed. It is many orders of magnitude greater than it was when we began our journey on this planet.