Some optimist wrote, “I think the earth can support 10 billion humans just fine.” The other day some greater genius insisted that twice that was totally sustainable. The highest figure I have heard so far was, ludicrously, 50 billion.
Years ago, before it became a thing to deny overpopulation, like it has become a thing to deny climate change, like it has become a thing to deny that nuclear power is safe… there was a box set of, I think, Blue Planet. It contained two bonus episodes. And if I remember correctly, while one of those episodes touched on overpopulation, the second was about what population of humans was sustainable.
Incidentally, while making the series, they had asked every expert, biologist, ecologist, engineer, every one, the same question. What, in their expert opinion, what is a sustainable human population. As you might suspect, there was some variation. A couple were as high as 4 billion, but the consensus was 2–3.
And consider, if there were 2 billion of us, instead of eight, that would be a biomass, of us alone, 2½ times that of all marine and terrestrial mammals combined. While if our livestock scaled proportionately there would still be a biomass of cattle, sheep, pigs, and etc., 3.75 times that of all the wild mammals combined. Despite the “Oh waily waily!” Pretense that two billion is too few people, that would still be a huge population of any one species.
So, even though I think your hopes for sustaining 10 billion humans is delusional, and actual qualified experts agree, I fear that we are going to find out the hard way. Because this population and our population 10, 20, 30 years ago was already burning up the natural world, on which our lives depend. And it is yet to be seen if we could ever hope to remediate the damage overpopulation has already done.
