Japan could lose 90% of its population and still have more people just in Japan than existed worldwide ~10,000 years ago. I don't know what the "ideal" number of humans is, but I know we could survive just fine with quite a bit fewer than 8 billion.
We would also have to revert to that level of technology because there wouldn’t be enough people to operate at each level in the supply chain to turn raw earth into wiz-bang computers etc.
I was just using that as an example, though I'm not sure 14 million would actually be too few to have that kind of separation of responsibilities. Assuming no genocide or catastrophe, by the time human population gradually dwindled back down to that level, we'd have hopefully settled on a fairly sustainable and automated existence.
This is still a very shaky ticket to bet on. Yes, the new crop of AI tools promises a lot of productivity gains, but for now they also need well-educated folks to operate them and integrate their output, and we don't quite know what the reliance of AI will do to peoples' educational interest/drive, etc. There might well be an overall downward spiral and loss of operating knowledge lurking there.
It would mean we reached peak capability as a civilization, and then we would be forced to rely on an artifact that can pull from that subset of knowledge to help patch together machines that broke down until we lost all the hardware to run the AI itself.
We went to the moon in 1969. The last moon landing was 1973.
The world population in 1969 was 3,625,680,627 [0]
The world population in 2020 was 2020 7,794,798,739 [0]
Today's world population is 8,029,731,569 [1]
We've more than doubled the world population in the 50 years since the last moon landing and no country has ever yet made it back.
Using your argument, I can unequivocally say that more people is bad.
In 1969, there were 324.23 ppm carbon in the atmosphere. Today, there are 416.43 ppm carbon in the atmosphere. [1] This does not even count species mass extinction, other pollution, etc. Even in 1969, there were sufficiently massive real environmental damage concerns to create the EPA within the same presidential administration.
This also does not even mention the massive resource constraints and conflicts that inevitably arise with overpopulation. this includes oil, water, lithium, rare-earth minerals, and possibly most important, phosphorus, which is rapidly running out, and when it does, the entire agriculture industry that feeds the current overpopulation will crash, along with the human population.
Humans would thrive with something like 1/8 of the population, especially with the level of technology, and will continue to advance.
Just consider that a miniscule 6.7% of people have a college degree [2]. That provides something resembling an upper limit on the set of people actively contributing to technological advancement. Interestingly enough, double that is about 1/8 of the population.
The view that "some is good, more is better" is just... to be kind, massively simplistic and wrong.
> Just consider that a miniscule 6.7% of people have a college degree [2]. That provides something resembling an upper limit on the set of people actively contributing to technological advancement.
Isn't that a bit like wanting to only take in high skilled immigrants without wondering where they're going to get their favourite food from home (which as a high skilled immigrant, I can tell you, food is immensely important to us).
We don't do this stuff alone, we need haircuts, streets cleaned, trains to run, people to make and deliver food etc. We all contribute.
Yes, I understand all types of people create valuable things, and I absolutely do not mean to imply that just because someone is not highly educated,they cannot provide something amazingly worthwhile. I also very much enjoy food from other cultures, and would not want it to disappear.
So, let's take a look at food - and some data.
Only 150 years ago, it required over 70% of the population to produce enough food for 100% of the population. Today, it is under 5% in rich countries, and about 65% in poor countries [0].
Obviously, given the uneven distribution of technology and knowledge, those people are today contributing to society.
But it is also true that fully distributing modern agricultural technology will make entirely redundant (to the maintenance of a technologically advanced society) something like half of the world's population.
And that is just an example from one industry.
The point is that declining replacement population does NOT automatically mean that the technological level of society will decline.
Correlation is not causation.
If anything, population increased as a result of technological advance — ability to generate more food, better shelter, better medicine — technology was not the result of greater population. Once we have the technology, evenly distributing it will require far fewer people to build and maintain it.
Let's take it a step further, and say we want to avoid using massive amounts of fertilizer and pesticides common in modern agriculture. That will STILL not require the same amount of people slaving in the fields. The technology that will enable scaled-up organic farming is also massively labor-saving — agricultural robotics, not only planting and picking, but most critically monitoring for and eliminating weeds and pests [1,2].
Yes, there will be a greater need for people fabricating and maintaining agricultural robots, but that will be dwarfed by the number today's slaving-in-the-fields-jobs that will disappear in a near future decade. If they do not reproduce at full replacement rates, we will still have a society that has both technological workers, and others who contribute much more to the culture, including authentic cuisine.
Everything exists within the boundary conditions of its environment. Humans, just like any other organism, can strip their environment of resources faster than they can figure out how to escape the environment or build a new one or whatever.
It's also worth pointing out that, so far, this is not the case. It may be prudent to be, well, prudent, but we're at an all time high in population and an all time low in absolute poverty. It's possible that more people is a factor in this, not less, and that those boundary conditions are never met.
Humanity goes extinct if sustainability and climate change don't matter. And so does a lot else. We've already ensured through our actions to date that what remains of our time on this earth will be miserable, but we might still stand some chance of not completely ruining the place.
A 33% reduction in the population of one country is a tiny step in the right direction, but still far short of making a significant difference.
That is not at all necessarily true. We have another 5 billion years or so before the sun exhausts it's hydrogen and starts substantially changing.
Applying even current levels of intelligence and knowledge (nevermind projecting even hints of the growth rates over the last ~10K years since agriculture, writing, etc. started), that is more than sufficient to develop resources for interplanetary and interstellar travel.
> Does sustainability or climate change matter if humanity goes extinct?
These can be linked, though. I have a lot of young people around me who are hesitant to have kids because of climate change and the period of instability their offspring would be born into. If we manage to address climate change, people may well enjoy the prospect more again.
> How will you know when you have addressed climate change? Will there be different climate models from today's, showing everything is now OK?
According to what I read in the IPCC reports, we already have those; it's how goals like ones under the Paris Agreement get derived. I'd imagine it's a mix of footprint monitoring to see if we are hitting targets, and updating models based on new knowledge.
The bottom line is that a lot of people have a sense of "we're doomed" these days that's at odds with having the energy to make plans for a long-term future, or to look forward to it. If we improve I'd hope the collective zeitgeist would shift accordingly, and give those people a better outlook.
My own point of view is ... tricky. I'm relatively wealthy and well-educated. Privileged, really. My kids would be among the most likely to be in a position to contribute to a better world, so maybe having kids is the best ticket to keep the world going. I feel like I should invest the resources I have been lucky to get into family and children. I'm nervous if they'd grow up to agree, however, because this is easy to think while living in relative peace and comfort.
IMO humanity going completely extinct has always been an unlikely outcome, at least from direct climate change causes like food shortages, rising seas, etc. Those are too solvable by just having less people around and/or in different places. Even secondary causes like war are unlikely because eventually one or both sides will lose the ability to fight across the Pacific and Atlantic, kill enough people the resource crisis is alleviated, or humanity and rationality kicks in eventually and agreements are reached to stop fighting.
The much more likely is life just gets really bad for a while or at the outside possibility things fall apart enough we slide back a few centuries in some industries. If we go too far back power becomes an interesting issue because we've exploited most of the cheap easily accessible power sources so successor civilizations won't have the easy coal deposits to power a second industrial revolution.
Far too many people in this thread are extrapolating a downwards line forwards for fifty years in the assumption that nothing will change and that nobody will decide to do things differently. Some of the Japanese people being born today - and there are people being born today, the number is not zero - will be alive in 2070.
What unites both questions of sustainability of the environment and of population is the question "what, other than money and its getting and spending, are we for?"
Nothing will change. It will only get worse. There's also people leaving the country. Short of a miracle nothing can fix Japan's issues. It's deep in its culture.
It's not a merit based society. Even if someone wants to do things differently it's almost impossible to push for it.
I think they’re implying the opposite. The world would be destroyed if the total population continues to grow. As of right now, we would need 5 Earths to sustain everyone’s current lifestyle, keeping in mind that more than half the world lives in poverty.
People voluntarily choosing to have fewer children is not going to cause the extinction of humanity. Consider that there are tons of people still having children, and that whatever genes they may have that predispose them to reproduce will, over time, tend to be passed on. Natural selection is a relentless machine of reproductive incentivization.
