Paul Ehrlich - The Population Bomb
By a spooky coincidence, Paul Ehrlich published The Population Bomb in 1968 in the same year that population growth rate peaked at 2.09%/yr. The global population that year was 3.55b. If that growth rate had been maintained ever since then we would have passed through 10b this year. So we're really lucky that 1968 was also pretty much when we transitioned from exponential growth to linear growth and hitting 10b is still 38 years away. It's easy to see now in retrospect that the demographic transition happened and come up with all kinds of reasons why it happened. It's harder to come up with reasons as to why Ehrlich should have seen it then. He was writing in a time when we'd had a 100 years or so of exponential growth over 1.5%/yr and in the previous 20 years it had been accelerating. So I think he deserves a break for being overly pessimistic back then.
10b, right now, and having got there so fast, would not be pretty. I don't think its going to be pretty in 2056 either, but we have a little more time to adjust.
https://en.wikipedia.org/wiki/The_Population_Bomb
http://www.worldometers.info/world-population/#growthrate
Data collected is currently following the medium fertility model closely. And with 2050 only ~30 years away, the model should be fairly predictable out to there barring black swan events or some full on collapse. They kept pulling back the date for 10b but it's been stable for the last couple of revisions. So 10b in 2050-2060 seems very likely.
Unless something else happens along the way of course, like women starting to have more children again, climate change conflicts and famine take it’s toll, pandemics or whatnot. It’s difficult to make accurate predictions so far into the future.
"We are now experiencing an unprecedented sustainability crisis caused by climate change, biodiversity loss, deforestation, habitat destruction, alien species, soil problems (erosion, salinization and soil fertility losses), pollution, water crises, overhunting and overfishing, overpopulation and increased impact per-capita. All these causes may lead to the collapse of human society. Therefore, it is not exaggerating to say that we need a new kind of science that may take us to a more sustainable future."
The problem is real, the problem is serious.