Why is population growth rarely discussed as a factor in climate change?

Among all the articles written about climate change and the various proposed ways to address it, very few mention population growth as a factor. With projections of 2 billion additional people in the next 30 years, the additional per capita energy use would largely offset technological gains in energy production efficiency, fuel economy and so on.

Why isn’t there any discussion of decreasing the population growth rate part of climate change mitigation strategy?

Probably because population growth in and of itself is only tangentially related to climate change. You could grow the population quite a bit but if you kept the current CO2 footprint of the average poor 3rd world country it wouldn’t impact climate change as much as the increasing demands when they go from poor to not so poor. For example, China has over a billion people in it. But it wasn’t going from 600 million to a billion that increased their CO2 footprint, it was going from being desperately poor and essentially agrarian to heavily industrialized and richer. Have a billion or even 2 billion dirt poor Chinese without access to electricity or cars for the most part would be a pretty small CO2 difference in the greater scheme of things. Having China go from agrarian to industrial giant with a large percentage of their population having access to electricity, cars and high tech has catapulted the country from being a country with a low CO2 footprint to being the number one producer of CO2 on the planet. And the Chinese have exported that, since they are basically doing the same thing…they are exporting their coal fired industrial tech to many poor 3rd world nations, doing huge infrastructure projects and further adding to the worlds CO2.

There is certainly a relationship between population growth and climate change, but it’s a tangential one. It would be better to say that both issues stem from the same factor, that being our technology and tech growth. You get the sort of population growth we’ve seen world wide in the gap between more effective medicine and agriculture and when prosperity cuts back on a population and it’s growth. When you go from, say, a per couple child rate of 7 or 8, with half dying before they are 20 to the rate of most prosperous countries of 2 or less. Even China is going through this, and it wasn’t their idiotic 1 child policy that got them there…it was already happening as they became more prosperous. But it’s the prosperity and increase in CO2 footprint that is changing the climate, not simply the population growth…especially since it’s generally the poorest countries with the least CO2 footprint that are growing the most, while those producing the bulk of the CO2 are not growing while their CO2 footprint rises due to that prosperity.

Perhaps because it runs into sensitive issues concerning religion and ethnicity.

Some religions take the “be fruitful and multiply” thing pretty seriously. Religions aren’t known for changing their positions based on rational arguments.

Overpopulation is more of a concern in poorer, non-white countries so this could be viewed as rich white people telling poor non-whites that they should have less children. Even if it’s preferable, it can still be awkward.

In countries where the balance of power between ethnic group matters, there may also be a game theoritic reason why all ethnic groups in a country may recognize that overpopulation is a problem but don’t want their own ethnic group to diminish in numbers and they’d sure like it if other ethnic groups reduced their numbers. Christians in places like Nigeria or Ethiopia are likely unenthusiastic at the prospect of Muslims outnumbering them 2-to-1 and that’s sensible if they look at Lebanon.
There’s also an economic element: The counter-intuitive thing is that without economic development and what it enables, there won’t be a stop to overpopulation. People in poor countries have a lot of children because 1) many are expected to die early or were expected to 1-2 generations ago and habits take some time to adapt 2) those that make it past the early years can supplement family income 3) as adults, they will serve as safety net in the absence of a welfare state. Once people have grown up in a place where the vast majority of children reach adulthood, families have enough money not to need child labor and the state offers a safety net, we can expect over population to be on its way to being curbed. But economic development will likely involve increasing pollution and climate change for at least a while or perhaps permanently.

You do hear about it, just not a lot. The reason why is that the climate change conversation is largely taking place in countries that don’t have positive birth rates, so it’s not a focus. The US birth rate is well below replacement and almost all of Europe is substantially worse. World growth is going to come from the global south, predominantly Africa and south Asia. The people pushing for climate change legislation are typically on the left side of the spectrum and there’s a certain justified queasiness about attacking what might be called ‘immigrant feeder’ countries for fear that the far right would co-opt that message for their own less than idealistic purposes.

One big reason is that there is not a direct correlation between population and consumption. One theory holds that people with fewer children will actually consume MORE resources, because they have to spend less money on child-rearing. So for example, a child-less couple has more disposable income, so they spend it on things like vacations and airplane flights that produce more waste emissions. If they had more children they would stay home and travel less, which would produce fewer waste gases. Likewise, a country with a big population and low GDP might produce less waste than a country with a smaller population but higher GDP. The GDP is more closely correlated with waste and consumption than the size of the population itself.

The other problem is that the biggest increases in waste come from manufacturing and energy sources. These are also only tangentially related to population. If a country uses lots of solar and nuclear power, they will produce far less waste than one that burns coal and gas. Once you’ve built the renewable and low-emission energy infrastructure, it doesn’t really matter whether your country has 50 million or 150 milion. Changing the economy and the technology has a greater impact than changing the size of the population.

This article probably does a better job of explaining it, although its a depressing read. https://www.vox.com/the-big-idea/2017/12/12/16766872/overpopulation-exaggerated-concern-climate-change-world-population

Because I got exhausted preaching ZPG/NPG in the 1990s.

Yeah. I suggest we need to be more efficient and produce less waste, and people roll their eyes. I suggest we need fewer humans, and holy shit… People react with an absolute rage that I struggle to comprehend.

Well, I usually roll my eyes at folks who suggest we need fewer humans because, generally, they don’t understand population dynamics and often suggest things that are either silly, stupid or impossible (or evil), to a problem that is already fixing itself and can’t really be ‘fixed’ in any case. The only way to speed things up will, ironically, have a bigger impact on climate change in the short term. But whether we force through a speed up in prosperity or not, it’s going to happen, and our population will peak and then start downward (unless we, again, come up with new technology that will extend life more radically, which will slow down the decline).

Like JB99 pointed out in post #5.

I have to add that a lot of what I experienced in past discussions here and elsewhere is that there is a bit of a Red Herring argument when the ones against dealing with the emissions problem want to concentrate only with the population issue.

It is like that because many who do raise the point insist that we should deal with it and not the emissions issue. IOW, just another argument in favor of “we can’t deal with it, so we shouldn’t do anything about it”. Thing is that if reducing population was the only way to deal with pollution, then humanity (specially in developed nations) should had never had been able to control water born diseases (with sewage and water works), able to control acid rain, control phosphates in rivers or lakes, limiting the damage to the ozone layer, etc.

Me too.

Back in the 1960’s there was a big concern about the perils of rising population. The population has more than doubled since then and, although many bad symptoms of that growth are readily apparent, there’s been no obvious catastrophe. Yet.

Many, even at this otherwise-intelligent Board, adopt the attitude “Population growth bad? Been there, got the T-shirt. Yawn!” I wonder if these are the same people who told their 11th-grade algebra teachers “Nope. You can’t take the square root of a negative number. Learned that in 7th grade. Yawn.”

Attempts to expand debate to discuss the unhealthy human population level are met with non sequiturs:

  • “Population may level off at ten billion.” (OK, but ten billion is still far too many.)
  • “Why do you want babies to starve to death?” (:eek: You’re the ones directing us toward a future catastrophe. I just want to identify problems.)

XT has it in one, with a caveat. The biggest cause of increase in population is improvements in public health. Babies don’t die at the rates they did and the elderly live longer. Generally speaking the reduction in birthrate tends to lag a generation from the start of the improvements.

Otherwise, yeah. The increase in CO2 emissions and population are due to rising prosperity and standards of living.
So, which of you Westerners is going to go explain to the non-whites that they must remain poor for the good of the planet?

Population levels don’t really have much to do with global warming.

Global Warming is simultaneously a manufactured, political problem and an existential threat. If we collectively got our heads out of our asses about “scary” technology like genetically modified crops, nuclear power, or large scale geoengineering, then we could feed the whole world, and a few extra billion people to boot, and house them all at a Western standard of living.

More likely, global warming will destroy us all because when is the last time we took our heads out of our collective asses?

High population eats wild land, for living space and for ag. Wild land is a better carbon sink than developed land, so this should be accounted for in the climate picture – the deforestation of the Amazon basin has actually affected weather patterns in a way that may accelerate the desertification of the jungle, which will remove a major carbon sink from the balance.

The US is neither the top GHG emitter nor even the highest per capita, but I would guess that its worldwide resource draw could account for a large fraction of non-domestic GHG output. It seems evident that raising the rest of the world to a comparable standard of living (thus thereby in theory throttling population growth) would be infeasible.

Overall, it is a complicated picture, in which population pressures are a consequential element.

Ah, there is the false dilemma that usually pops up in discussions like this one, as it was mentioned before even the ones looking at the issue are not saying that to the “non-whites” (a bit on the prejudging side uh?)

I agree with supporters of the climate agreements that this attitude coming from your post is like a very fat guy at the table (The USA) complaining that the new skinny and growing guys at the table are eating good now. Forgetting that the agreements made do not say that (remain poor you!) at all, the developing nations will not do the same forever and that there are changes already going, even in the developing nations.

To put it in admittedly simple terms, there are 2 main factors: High vs low population, high vs low wealth. In a 2x2 matrix, that gives us 4 options for individual regions and the world as a whole over the coming couple of centuries:

  1. Low pop + low wealth: The world for humans ever since we came down from trees up until the industrial revolutions. We’re not going back there, even if Roussean hippies would have you believe it’s be great. Not only would it be worse than climate change but it’s just not going to happen no matter how much it may be desired. Short of something quite unusual in zoology (see options 3 and 4), an animal population will increase its numbers to the carrying capacity of its environment and nature’s corrections when that is exceeded aren’t gentle.

  2. High pop + low wealth: The world Malthus predicted. I don’t think many people want that either. While other animals can bump against their carrying capacity through excessive reproduction, humans also use up that carrying capacity with the technology they use to make goods and services which we call high wealth.

  3. High pop + high wealth: The most polluting option and the one we’re headed for. Also the option which will reduce birthrates within 1-2 generations and after several generations of sub-replacement levels will eventually lead to option 4

  4. Low pop + high wealth: Where we’ll end up 1-2 centuries from now, after much damage may have been done by pollution. Discussions should be about how to get there in a way that minimizes suffering.

I agree with the people above that population growth is (somewhat) talked about, doesn’t necessarily have as much prospect for improving climate change as reducing emissions, and in any case touches more hot button emotional issues that might derail the conversation.

But in any case, taking action to reduce population is not something that most people are in a position to do something about. The normal age of childbearing in Western countries is about 20 to 35 or so (give or take some for outliers). Anyone who’s outside that window isn’t currently in a position to take active action about their conviction that population should be lower, apart from haranguing other people, which never goes down well. The median age in Western countries is generally around 37 or so - so at least half of the population (more than half the adult population) are in the position where their decision is already made, for good or ill. But you can make a decision about reducing your carbon footprint today, and work on it as much or as little as you like, whoever you are.

Maybe you should take a more nuanced look at it and try and understand how population dynamics actually works. Then you’d see that even cutting birthrates well below replacement level at this point would STILL result in that 10 billion function because people are living longer. The only way to really prevent that is to kill off a few billion right now, today…and best make sure it’s a few billion of the younger ones to do it right.

And it’s a problem that’s already solving itself. Only a few very poor nations, generally in Africa are well above the global average of 2-3 children per couple, and even in those countries the shift is downward, just not as fast since conditions in those countries are still bad. For a view on this that isn’t about someone ignoring you with a yawn, I suggest this video by Hans Rosling : https://www.youtube.com/watch?v=FACK2knC08E

Nah. The older ones. We’ll establish a cutoff, say 30 years old.

I have no idea how you get your conclusions out of what was posted there. ISTM that AK84 is just pointing out the reality (my one quibble with his post is that I did address public health as a big reason for the population growth, I just tied it to prosperity which I think is a better measure). Unless your issue is with my post? In which case, I’m still not seeing it. Your analogy of a fat man at the table seems to be a pre-recorded come back to an argument not being made here.

The reality is that prosperity has a lot more to do with climate change than simple population growth. Population growth and climate change are only related in that they both stem from the same root cause…human prosperity. Population growth shot up because in the 18th century we started developing medicine that started to cut into child mortality, and in the 19th century we further cut into that as well as increased agriculture. It took time for people to stop having large numbers of children in the anticipation of losing half or more. In addition, you had improvements in health that had more people living longer as well. So, there is a relationship there, but it’s not the one the OP was asking about, and the root cause of climate change is prosperity.

The reality, though, is that as emerging nations become more prosperous they WILL expand their CO2 footprint. At the same time, long established countries are either expanding their own or dropping over time, but it’s a small drop. There is no way for the fat man to prevent the skinny nations from going through this trajectory, and, frankly, from a population perspective we don’t want to. Prosperity is what is going to rein in population growth after all. But since we are at peak child already, there is not much we can do to prevent our population from rising to 10 or even 11 billion before it starts downward. It’s going to happen. And those people ARE going to become more prosperous and increase their CO2 footprint, even if all they do is build a bunch of solar panels and windfarms and not what they are actually doing which is trading their feet for bicycles for motorcycles for cars and trucks and so on.

What options are there for discussion? Wait for a famine? Start another world war? Promote a lot of little wars? Pestilence? Pandemic? Encourage suicide? Voluntary sterilization? These are all time-tested ways of decreasing population growth. I imagine the conversation might get a little testy from time to time.