I don’t know the optimum number, but have been told by sevral teachers when I was in school it could support 11billion.

I don’t know how there could be an “optimum” population. Optimum for whom? One could argue that the earth would be better off with no humans at all. Certainly more resources for fewer people is better than fewer resources for more.

That said, I think we can support more, but not too much more.

It took 200,000 years of human history to get to 1 billion; it took only 200 years to get from 1 billion to 7 billion.

Yeah, there’s empty space, but what about all the space needed for agriculture to feed those additional people and provide lumber to build housing for them? What about the fact that we can’t even feed all the people we have now for various reasons?

I don’t think we’ve exceeded it; I’m no “overpopulation” alarmist, but if the population continues to soar as it has for the past century, then we will exceed it soon.

Zero.

The question needs more explanation and context.

If we’re talking about the amount of space available, then population could be in the 50 billion or more.

If we’re talking today’s technology, probably 10 billion. If we are talking near-term future technologies like advanced agriculture, probably 15–20 billion.

To answer this, you need to really define some time and technology parameters.

Optimum? About 4 Billion. That was a good sustainable population without pressure on any systems or structures.

Agree with @elbanditoroso, although according to recent statistics (posted in another thread), the birth rate is at a 30 year low currently.

https://www.npr.org/sections/thetwo-way/2018/05/17/611898421/u-s-births-falls-to-30-year-low-sending-fertility-rate-to-a-record-low

Around one million would be fine. We’re close to eight billion which is too many especially with the life style we all aspire to.

What a coincidence. Just the other day I asked my friend what if a secret group of scientists from all over the world….or a goverment discovered an “intelligent virus” that can be secretly deployed globally in days, infecting several billion humans they pre-selected for extermination actually uses it?

Would that solve humanity’s future population problems?

Could there already be a horror sci-fi novel written with the same plot?

I don’t know the number, but I think we can fit many many more people if we change our ways.

We need to become more of a United Earth, share technology and resources, build up, so green spaces are preserved. Rape the land less.

Pie in the sky probably.

Never going to happen @JLeslie human greed will always get in the way of a united earth with everyone getting along.
Certain people will always want it all, and exploit everyone in their way to get it.
The earth will be a raped lifeless planet before people will actually work together for the greater good of all.
Look at how much climate change is scoffed, and disbelieved by the wealthy now,no matter who tells them it is a very real thing.
I have no faith in people working for the greater good of all the people and the planet.

Believe it or not, I agree with you @SQUEEKY2. My husband and I were discussing it and the effects on the planet, and he was passionate and informed. So I said, well honey, why do you keep throwing your recyclables in the trash and won’t comply with the recycling bins and compost then? He stuttered and just said it was too much trouble.

To me, that is the biggest problem. Apathy and laziness, good intentions don’t fix the problem.

There are a group of experts, supposedly and quite certainly, who have erected a stone monument outside Atlanta, Georgia, who claim the maximum amount of humans should not exceed 500 million.
Air, water and soil pollution will get us all eventually, as will antibiotic resistant infections and illnesses.
The planet is dying beneath our feet, too, and lower life forms are disappearing already, and in great numbers. Bees, frogs, corral reefs, insects and small animals of all kinds in places like Puerto Rico.

@KNOWITALL Growing up I, more than once, was told by my mother that: “The road to Hell is paved with good intentions”. Another one of her wizened Scouser idioms.

Comfort wise, probably less than 2 billion creates the most comfort. Life support wise – who knows. Maybe triple where we are now?

Guess it all remains to be seen at this point.

Agree with @zenvelo – about half of what we have now (ref. Thanos). Humans are using resources like there’s no tomorrow. I see shortages of food, water, energy, etc. in many places already.

Perhaps, 10 billion.