From the Wikipedia article on Human overpopulation:
> The concept of overpopulation is controversial. A 2015 article in Nature listed overpopulation as a pervasive science myth. Demographic projections suggest that population growth will stabilise in the 21st century, and many experts believe that global resources can meet this increased demand, suggesting a global overpopulation scenario is unlikely.
The first statement does not follow automatically from the second.
It is not currently run in a sustainable way. It can be, and people are trying change it so it is sustainable. This is hard, but does not appear to be impossible.
which creates something of a tautology. Ability to maintain a population in the long run implies 'sustainable'. I guess that given nutrient vats and fusion power we could have a sustainable population of one trillion.
It's worth considering what the point of having so many people is....
>Once you answer those questions, is there a number of people you'd like to propose as optimal?
That's a good question. I'll take a shot at it even though you're not really asking a question but making a point.
Let's say that the one thing that people bring to the table is intelligence and the ability to design complex systems, it's something of an end-run on evolution.
How large a population do you need to build modern semiconductors, discover exoplanets, solve physics problems, do a passable version of the arts?
I would guess something on the order of 500M-1B which is roughly the number in 1800. You get most of the good and lose most of the bad if you're even slightly careful. The edge conditions of atomic war or a truly large nuclear incident still exist but the rest of our sins cover up well over time with that population.
> It is not currently run in a sustainable way. It can be
Can it? That remains to be seen. So in the meantime I would say we are already overpopulated.
To be fair, your statement probably means that we have the resources and technology to run the world in a sustainable way, and I would agree with that. But then we also likely have the resources to end hunger, poverty and war, yet those have never been the world’s priorities.
When will it be a priority for humans to run the world sustainably? Who knows. But right now it’s definitely not sustainable.
> But then we also likely have the resources to end hunger, poverty and war, yet those have never been the world’s priorities.
And yet, all of those things declined; in the case of poverty the decline is in both absolute and relative terms.
Certainly more needs to be done in all of these things: we only succeed when we reach the destination, not just when we walk the path. Conversely, every step on that path brings us closer to success and is a reason for optimism.
To suggest that overpopulation is controversial is itself absurd, as it is fundamental to the science of biology[1]. That a species can reach numbers where their environment and habitat is depleted or otherwise unlivable is fact, not controversy.
"Population Control" is certainly controversial, though, as it should be. And, though controversial, it should be considered seriously. Many environmentalists lose their credibility by speaking of "sustainability" on the one hand, but then disputing overpopulation on the other. We need to impact the earth much less, and keeping our numbers down is a very effective way of doing so. That, plus using energy and resources more cleanly and efficiently.
The question about human overpopulation is not whether there can be overpopulation, but whether the often popular claim that the earth can not sustain the current or the projected future human population is true. The latter absolutely is debatable - there's no clear evidence that it's impossible (i.e. there's no technically feasible way) to sustain the current or the projected future human population. It absolutely is true that if we maintain the current level of CO2 emissions, it won't be sustainable. But that's not an evidence for overpopulation. If we sustain the current level of pollution, it likely will not be sustainable. But that's once again not an evidence for overpopulation - as we know for most of our resources that there are technical alternatives that can drastically reduce / eliminate them. We know there's more than enough energy. We know how to make our economy carbon-neutral. Most pollution can be controlled. The urban land takes up much less than 1% of the earth land - and we expect the world population to peak around 10B by 2100 (vs 7.7B today). No reason to believe we'll run out of land. There's more than enough headroom to improve the crop yields in poor countries.
In the grand scheme of things, we - humanity - know mostly how to create a sustainable technological system that can support 10B population. Whether our politics will allow us to get to such a system is a entirely different problem, and THAT might be our undoing, but I'd argue that's not really an overpopulation problem.
Also, the population growth is largely a side-effect of demographic transition - https://populationeducation.org/what-demographic-transition-.... i.e. it's a transitional side-effect of reducing the human suffering. The only humane and equitable way to move forward is to accelerate the demographic transition (i.e. improve the economic, health, education, etc, systems of all countries in the world to get them to stage4 at least). And, thus, "keep our numbers down" is not only inhumane or inequitable, that's ineffective - the developed countries already mostly stopped growing - e.g. https://www.statista.com/statistics/1251591/population-growt... - and it's mostly the poor countries that are growing - i.e. https://www.statista.com/statistics/264687/countries-with-th... . There's no other humane way to stop poor countries' population growth - the most effective way is to improve their economy, improve their health and healthcare systems, and improve education.
"The question about human overpopulation is not whether there can be overpopulation, but whether the often popular claim that the earth can not sustain the current or the projected future human population is true"
So only human overpopulation is impossible, you're saying. I think you're wrong on that. We're special relative to other species -- but not that special, and not immune to it.
"In the grand scheme of things, we - humanity - know mostly how to create a sustainable technological system that can support 10B population. Whether our politics will allow us to get to such a system is a entirely different problem, and THAT might be our undoing, but I'd argue that's not really an overpopulation problem."
Is the goal to pack as many humans onto this planet as is possible?? That certainly isn't my goal, at all. With our technology, we don't need vast numbers with which to build pyramids or plant fields.
> So only human overpopulation is impossible, you're saying.
No. That is not what I said. I'm saying whether human overpopulation is theoretically possible/impossible is not the question - as the answer is very clearly yes, if the number is too large it will qualify as overpopulation.
I'm saying the relevant question is whether the current population and the projected future population would qualify as overpopulation, and I'm saying that absolutely is debatable.
> Is the goal to pack as many humans onto this planet as is possible?
No. The goal is to find the humane and equitable way to reach sustainability. I'm claiming sustainability (with current or projected peak human population of ~10B) is entirely technologically possible, and "overpopulation" talk is mostly ungrounded, not backed by any real evidence. At the same time, it's also clear the current state of things is NOT sustainable, and that we'd need to change our technological systems in order to reach sustainability, and I do admit that it's entirely possible and somewhat plausible that our politics will keep us from reaching the sustainability.
Improved quality of life and reduced infant mortality are shown to reduce population growth by creating incentives for people to have fewer children. If you want fewer people, then you want to improve the material well-being if as many people as possible. As it stands, the global population is projected to peak at around 10 billion people some time this century, per current trends.
I think this is incomplete. In every case so far a reduction of infant mortality and improved quality of life are coupled with power structures that increase the amount of productive output that is captured by a family, increasing the relative cost of producing children.
I don't doubt that wealth can be a factor, but those systems are a whole lot more complicated than that. Money+Low Gini = Low birthrate is a meme as much as it is a primary driver.
As you’re asking in good faith I don’t see why you’re being downvoted.
Population carrying capacity is difficult. We know that given a particular level of technology we can support a particular number of people with global resources in the short term. Intuitively it seems like we’re wrecking the environment and we’re in for a nasty fall when we exhaust those resources. However, Malthusian predictions like that - so far - have a bad track record, because with more people comes more innovation, and so far that innovation has been increasing carrying capacity faster than population growth.
Ultimately it looks like the world population is going to stabilize as most people seem to prefer smaller family units once they achieve “western level” of child survival expectations and material wealth. Strangely enough it may be harder to maintain a stable population with our consumption habits if it means that technological advance slows down.
That said, for most people all the above is unimportant compared to caring for the living. Preserving and extending life and quality of life is fundamentally good, and shortening human lives to “save the planet” is not. So while you can have the macro level discussion along the lines of “do we really want the population to increase,” for most people if you venture into “should we just let the people who are already alive die sooner than they must” is pretty offensive.
I just assume that any population level that can't be maintained on pre-20C. technology is probably dangerous. You'll either see a crack-up in terms of society and/or resource depletion at some point.
To be fair to the GP, this isn't the point they're making. Your argument would be valid if they were positing "it's not like it's me who's going to die."
They're asking, in good faith, if the effects of pollution-related deaths would have a net benefit to the world due to overpopulation concerns.
Most people die due to various diseases / accident / suicides, thus extending human lives collectively means reducing those human suffering. Implying extending collective human lives as "bad" is basically declaring you don't care about people's suffering and that you'd rather choose more suffering.
There's still a pretty reasonable argument to be made that 11 billion is not a sustainable number.
I'm not suggesting we start killing people, but we will seriously need to think about how we manage the finite resources of the planet with >1.5x the number of people.
