*cough* Having just graduated from the biggest demography faculty in the UK... *cough*
That link raised some good points that have been addressed ad nauseam by respected demographers, but in a very biased way. Heck, one of the authors is a founder of SEVERAL Christian family 'foundations' and the other is a disgraced academic (kicked out of Stanford for breaching ethical rules which resulted in other academics being denied access to China) hated both in the West AND China (served in the US Navy in the Far East and adopted Mao as a surname...) with NINE children.
It's pretty obvious that they should not be a go-to source regarding whether the World is over-populated or not. Even the references they choose to support their assertions are questionable, with not a single demographer quoted (I don't count Malthus as one, even though he is regarded as one of the fathers of the field).
An overwhelming number of experts, from biology, social sciences, demography, even NASA, all agree that the world IS overpopulated due to a variety of reasons.
1) Whilst it's true that food production has kept pace with population growth, and sure, human ingenuity may save us again like it did in the 1960s, the odds are stacking against that outcome more so than ever thanks to climate change and environmental degradation combined with the changing lifestyles of those in developing countries and the persistently wasteful lifestyles of those in developed countries. Sure, we MAY
invent some wondrous new technology that creates enough food for everyone and saves the environment... but I doubt it. The point about human capital increasing the prospect of technological advances isn't really true either, because quite simply, the vast majority of the current human population are not educated enough and do not have the opportunities required to make a difference. Continuing to grow the population at the same rate of the last 50 years will not help.
2) I don't understand their point about freshwater withdrawals keeping up with population growth being a good thing? Like, sure, but it's a finite resource and more and more places are becoming reliant on imported fresh water. It's an established fact that we are withdrawing more fresh water than is being renewed naturally through the water cycle.
3) We have
grown exponentially and some populations still are depending on the time scale and measure you use. We've reached peak child, for sure, but population momentum will take decades to slow down now that the bases of so many populations have been increased. That's one reason why the estimate for world population in 2050/2100 etc keeps changing. We just cannot forecast how all of these children entering fertile ages are going to behave in each contextual setting with any kind of accuracy.
Their assertions about Europe's fertility aren't entirely accurate either, claiming France and Britain will cease to exist... yet both have TFRs above 2.1, and Britain's is increasing. Some of that is due to immigrant fertility sure, but a lot is natively driven, and those generations of children born to immigrants will be assimilated as British people, as has happened for centuries. It's not just European countries who are struggling with declining fertility, although many of the countries that experienced lowest low fertility (TFR below 1.3) have reversed the trend since the 1990s.
It is interesting that they don't mention anything about China's low fertility being a massive problem for the future considering one of their authors affiliations (married a Chinese lady). Heck, there may not be a World in which the EU could fall to 59 million by 2300 if China goes to hell.
4) The rest of their "fun thoughts" are banal trivia. Not sure what purpose they serve. I'm sure we could all fit on the moon... so what?