First, global population:
So, as of this writing, it looks like we’re going to get to around 11 billion humans by the end of the century. But the global number obscures important regional differences:
It looks like natural population growth, excluding immigration, is already leveling off or declining in most regions of the world, with the huge exception of Sub-Saharan Africa. So, what are the biodiversity trends in these regions? Do they track population trends? Take a look:
Granted, the Living Planet Index doesn’t cover most species but it’s a pretty good proxy for the health of the land-based biosphere. And from this chart, it’s clear that the relation between regional population growth and biodiversity is complicated. True, Africa’s burgeoning population most likely drives habitat loss through overfishing, overhunting, overharvesting, and the expansion of agriculture - but what about Latin America, with it's relatively low fertility rates? Of course, habitat loss is the primary villain there as well, but driven more by global markets than local demand.