> It is quite likely that we can feed 7bn people.

We could probably feed a lot more, if we crammed everyone into small cages and fed them like factory farmed animals.

The question is why you would want so many people living like that? You are already indirectly pointing out that meat will be off the menu for future generations and I am sure there will many other things that will need to be sacrificed as the population increases (for example, fish populations don't sound like they are keeping up with demand). And at some point there are going to be some hard limits on how many people can be fed.

Do you mean feed them all soy mixed with wheat? Remove all meat production and most of the water expensive fruits?

It can certainly be a palatable diet, the wide variety of vegetables can be kept. It will be hard to convince Asians to eat much less rice though.

> It will be hard to convince Asians to eat much less rice though.

that's an odd thing to focus on. Moving people off meat & cheese would do a whole hell of a lot more than moving people off rice.

There's also some interesting work being done on growing rice in brackish water which could turn some unarable land to arable.

Farming is also mostly an energy problem. Assuming cheap energy, you can create hydroponics that scale vertically. Highrise farms, and they could consume electricity during off-peak times when it is extremely low cost.

Water is also not a problem, we are surprisingly good at treating water, can even turn saltwater into freshwater given sufficient energy.

We don't need to do that. Earth could support a population of a trillion humans so a few 10s of billions is of little concern.

I don't understand your optimism at all, considering the consequences of pollution and global warming will likely create violent changes and huge migration movements around the world that will lead to a lot of conflicts and wars.

Perhaps the issue is what people really want, not the number of them. Trump proved that at this time people don't really care much about pollution/climate change(at least the majority). One guy in the US may pollute the environment more than 10 in Norway so it's not about the number of people but about the choices of each individual and the community as a whole(i.e the government)

I think your maths is flawed, unless the 10 in Norway can produce negative pollution that outweighs them and the over-consuming others (in your example from USA), AND produce other environment preserving actions (reducing acidity of the oceans, preserving species diversity, inhibiting climate change, etc.) then we're still going to continue to force our own early extinction.

My point is that we need better policy not less humans.

I think we need both.

It's not about just feeding people and simply keeping them alive.

• Can you do it without taking away resources from other species and destroying their habitats?

• Will every person have enough space, physically as well as socially?

• Will all people have access to all the comforts of human technology?

• Will they all be able to contribute to human society?

• Will they be allowed to attain happiness, contentment and acceptance even if they cannot, or choose not to, contribute anything?

• Will everyone be able to find a partner?

• What is the endgame of the human species, anyway?

Of course we're biologically-rigged to believe that multiplying indefinitely is justifiable, but what's beyond that?

>> Will all people have access to all the comforts of human technology?

You worry too much. 500 years ago humans didn't have any advanced technology and they felt pretty comfortable. Now just look at all these homeless people. Do you think they have all the comforts of human technology?

People should have opportunities to advance within the society but not everyone wants that anyway. So as always there will be cool jobs and boring jobs.

Population growth will only accelerate technology. Would you prefer 1 developer working on 1 project or 1000 working on 1000 projects?

> 500 years ago humans felt pretty comfortable.

How do you know that

We have writings about how they lived and what they loved to do. We also know that humans adapt quite easily to the environment.

I don't doubt that people can be content with agrarianism, but worth remembering the inherent bias in recorded history towards the rich -- before the 19th century it seems very few people could read and write. Textual records are views of people who were relatively wealthy. I think that's true across cultures?

If you look at historical records of slavery, for example, you'll find "most people prospered", the people dying in cages weren't writing journals.

You have the writings of people 500 years ago who could write. That was not that common.

Humans can adapt to sleeping soundly next to a literal pile of garbage and feces (homeless drug addicts that I’ve seen in some third-world cities) but that doesn’t mean they “feel comfortable.”

The development (demographically and otherwise) in many first-world countries basically means many people will have to go back to a standard of living comparable to the one our parents/grandparents had in the 70's, and we won't accept it because other parts of the world are seeing improved conditions.

> Poverty is falling dramatically right now, and is falling faster than the UN ever predicted

True. But it might be temporary. See https://en.wikipedia.org/wiki/Earth_Overshoot_Day

I agree, the negativity is unreasonable. Yes, there are very big issues facing our species. But I think we're showing a good track record in fixing those issues. Not a great record, but a good-nuf one.

The late Dr. Hans Roslings' book Factfullness is a fantastic antidote to the negativity facing us. Before you go on, please take this quick quiz to see if you are smarter than a chimp: http://forms.gapminder.org/s3/test-2018

The first time I took the quiz, I got 2 right out of 13 questions. I did much worse than a chimp would have.

Factfullness is an easy read and well worth the time. In fact, you can read it for free here: https://archive.org/stream/FactfulnessByHansRosling/Factfuln...

Bill Gates gave the book out for free too; that's how important he thought the book was.

Factfullness goes into much greater detail (with MANY sources) on why and how the world we live in is actually getting much better.

> please take this quick quiz

Question 11 says none of the species have become more endangered since 1996 - except that whilst the general classification for black rhino hasn't changed from "Critically Endangered", three subspecies were declared extinct in 2011. Which is definitely more endangered, surely.

The situation for the environment is that bad; far worse, in fact, than most media is willing to honestly report. The Earth is undergoing a mass extinction event, as nonhuman species are pushed out to make more room for humans and our emissions.

Maybe instead of struggling to feed another 4bn people, we should be trying to educate girls and women and give them the tools they need to control their own reproductive choices.

I think we probably have to handle population growth at a societal level and not leave it down to personal choice and hope things will improve.

I'm not sure humanity has the maturity to do that.

If we can't sustain the current population without destroying the environment now, how are we going to do it with more people at an ever increasing average quality of life? This kind of attitude is how we got into this climate change mess in the first place.

You're looking at it from a zero-sum perspective when in actuality the ever steady march of science and technology means our situation is anything but zero-sum.

It never hurts to be cautious, but total pessimism isn't warranted either.

It doesn't matter what advances science makes. We have the technology right now to stop global warming, feed everyone, etc. But we aren't doing it, and this hand wavey attitude is part of that problem. I'm not pessimistic about the situation, I'm just treating it seriously like it deserves.

>We have the technology right now to stop global warming,

Not sure what you're referring too.

It is zero-sum if you are talking about the proportions of overall wealth that go to different demographics at any given time.

People like to trot this 'not a zero-sum game' line out all the time as if it is somehow meant to make us feel better about the grave imbalance of wealth we have currently on this planet.

We already have the resources to feed and cloth everybody to a good standard, but it would require some sacrifices on the part of many wasteful developed nations, which they simply will never do.

Plus, if you want everybody to have a modern quality of life even within the confines of a developed nation, some greedy people are going to have to start paying more in wages and taxes and accept that the social contract and safety nets are the only thing between themselves and an angry mob.

By expanding into the universe.