This has been studied long time ago by scientists such as Alfred Sauvy [1], who concluded that overpopulation is not the cause of sustainability crisis, and that greenhouse gas is the major cause. In particular, limiting the growth of population has few impact on the production of greenhouse gas, whereas changing the means of energy production and consumption is much more impactful.
Moreover the world population is expected to be less than 12 billions in 2100 [2], which is plainly sustainable. This is mostly due to the demographic transition, a pattern observed in most countries, where the fertility rates decrease over time. More specifically I recommend the excellent book of Emmanuel Todd and Youssef Courbage on this subject [3]. The authors argue that in most countries throughout history, when both the majority of men and the majority of women know how to read and write, then the fertility rate decreases, and a revolution becomes imminent.
[1]: https://en.wikipedia.org/wiki/Alfred_Sauvy
[2]: https://www.un.org/en/desa/world-population-projected-reach-...
[3]: https://cup.columbia.edu/book/a-convergence-of-civilizations...
In a simulator, could you have 12 billion people with their needs met, living fulfilled lives and continuing into the far future? Yes.
Is there a political and practical way to reach that state? No. "One study estimates it would take just over 5 Earths to support the human population if everyone’s consumption patterns were similar to the average American." Any US government that tried to bring America's environmental footprint down to a sustainable or fair level would be voted out. It doesn't matter whether it would be gas taxes, meat taxes, per mile taxes, flight taxes, carbon tax and dividend, building renewable energy in less developed countries, or any other scheme. It doesn't matter if it was targeted at the ultra rich or the middle class. The sheer scale of it would cause Americans to vote out the government. And the same is true for any democracy and plenty of the non-democracies too.
There's programs to give efficient LEDs from comed to people for changing it slowly.
We're not even vertically farming at scale yet.
There's a lot of room left for densifying human civilization. Seems like 10x should be achievable.
Why?
Why isn't 8 billion enough? Is there a plastic ring prize if we hit 80 billion?
Or are you talking about squeezing the 8 billion we have now closer together?
Perhaps consider that those 80 billion souls will contain Einsteins and Mozarts.
People are having fewer children, as living conditions, education, and acces to TV increases the reproduction rate falls.
Ideally we'll level out at 6 billion or so.
You haven't given any good reason why the earth should squeeze as many upright aquatic apes on it as possible yet.
Oh good, we don't ever need any more then. /s
> Ideally we'll level out at 6 billion or so.
I doubt there's any single ideal population size, because the impact of each individual varies so widely. In the future, when we're all living 100% solar powered regenerative net-carbon-negative lives, the problem will be that there aren't enough people to offset warming caused by volcanic eruptions, meteor impacts, and overpopulated wildlife.
Always handy, the point (lean back, look up) is we don't need 80 billion as a prerequisite to have more - that's a weak (to be generous) argument.
> I doubt there's any single ideal population size, ..
It's bounded by an upper limit of humans living like turkeys in a turkey farm and tossing the weak in the chipper to blend back in with the feed . . . is that your ideal mode of life?
The Earth is nice example of a complex system with many interconnect parts maintaining a relatively stable for millenia feedback regulated environment.
What is the argument for pushing human population to 80 billion, and at what cost does that come in terms of human living standards and the other non human life we share the planet with?
Your claim, unproven. My point is that 80 billions souls will produce 80 billions souls worth of art, science, literature, and culture. Which sounds divine. Why would you be opposed to such a thing if it can be accomplished sustainably?
> It's bounded by an upper limit of humans living like turkeys in a turkey farm and tossing the weak in the chipper to blend back in with the feed
Seems that you have a dark turn of mind, which explains the pessimism.
> What is the argument for pushing human population to 80 billion, and at what cost does that come in terms of human living standards and the other non human life we share the planet with?
Humans have lived regeneratively and sustainably in the past. We seem to be in the process of figuring out how to do it in a less labor intensive manner presently. I do my part to live sustainably, and I believe in humanity's ability to innovate and adapt and to address complex problems. Seems like you feel differently.
Plainly sustainable without fossil fuels? From what I can gather, the majority of farming, construction and transportation (including of farmed goods) relies heavily on fossil fuels.
This sounds like magical thinking. Even making the huge leap to say that cultural output would somehow scale commensurate with population infinitely, what does that actually look like in a reality with finite time and attention? I think we've already passed the point where anyone can keep up with all the cultural output (music, literature, graphical media) that is released each day. This idea of a cultural smorgasbord where we all get to sit back and enjoy a buffet of art is a dream that can only exist in the most idealistic of vaccuums.
> I think we've already passed the point where anyone can keep up with all the cultural output (music, literature, graphical media) that is released each day.
Good thing that's not necessary for one to benefit from it. I, for one, am happy to benefit from all the medical innovation I can't keep up with.