Boris Johnson thinks the world has too many people.
“Too many” is of course a value judgment—in part, in fact, an esthetic judgment, as Johnson’s article makes clear. On the one hand, there is plainly some limit to the number of people the earth can bear. A trillion is a certain upper bound; a hundred billion a very probable one; ten billion arguable. On the other hand, it is impossible to prove that the current 6.7bn is, or is not, past the limit. Appeals to the historical record are unconvincing, as the historical record includes no instances of a world population at 6.7bn and increasing.
Inside the overall problem are lesser, but more immediate ones—the ones Mark Steyn has been drawing our attention to—mainly problems of differential increase. Populations in Europe and North Asia have turned the demographic corner, and are actually decreasing, or soon will be. Elsewhere, in the Muslim world for example, the same process is under way, but a generation or so behind. In some other populations, the process hasn’t even visibly started.
Probably Ma Nature will decide the issue for us. It’s still worth discussing, though.