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“Most demographers say we will hit 9 billion before we peak...” I believe this thinking is very out of date at this point. The 2017 UN Population Prospect rep

by xefer 9y ago

“Most demographers say we will hit 9 billion before we peak...” I believe this thinking is very out of date at this point. The 2017 UN Population Prospect report has the World population at 11.2 billion and still climbing by 2100. The population of Sub-Saharan Africa alone is projection to be over 4.1 billion which I have to imagine will be nothing short of a cataclysm if it actually gets to that. The data here is stunning: https://esa.un.org/unpd/wpp/Graphs/ https://esa.un.org/unpd/wpp/Graphs/

mac01021 9y ago
> 11.2 billion and still climbing by 2100. They really don't think any physical constraints are going to get in the way of that? There are only so many fish in the ocean.
- xefer 9y ago
  The biggest natural constraint was nitrogen fixation which places a natural limit of around 4 billion people. But artificial fertilizers basically took the lid of that and the population has been exploding since been the process was first industrialized. https://pdfs.semanticscholar.org/9ef1/254c1b7626ae1c70f0718c0f811d11d990da.pdf https://pdfs.semanticscholar.org/9ef1/254c1b7626ae1c70f0718c...
- WalterBright 9y ago
  By then people will probably be mostly eating food created by an industrial process.
- nl 9y ago
  The short answer is that there are no real physical constraints. BUT there are some fairly important practical issues around unequal access to resources: some places have too much water and some don't have enough. Those kind of problems may lead to war, but probably won't stop population growth (short of it going large-scale nuclear or biological).
  - oblio 9y ago
    Population growth in many regions has already plateaued. At least the natural change. Europe, North America, Russia, China, Japan. The main outliers right now are India and Africa. But even those are expected to cool off after their initial burst. The true constraint is administrative capacity: will these countries be able to grow their infrastructure and improve their resource management before they turn their countries into deserts? India will probably manage to, but some African countries probably won't. It's going to be quite bad for some unfortunate people living in these countries...
    - pbhjpbhj 9y ago
      When countries packed with people grow resource scarce then the richer nations either share their resources, commit genocide by starvation, or go to war to keep the resources they have. We can pack in more people but not if we hope to raise the living conditions of all those people. IMO those billions more are mainly going to be living hand-to-mouth in shanty towns. Whole countries living like that have little to lose by going to war to gain resources ...
- jwfxpr 9y ago
  To be fair, it makes no predictions that the global population of fish will be >0 in 2100.
- ars 9y ago
  > They really don't think any physical constraints are going to get in the way of that? With enough energy you are not constrained by resource limitations. For example irrigate the desert with desalinated water. It's a really big planet, you could fit a lot of people on it - and animals as well. It's all about energy.
  - pbhjpbhj 9y ago
    Hmm, heard about the plummeting insect populations? Artificial pollination is possible but costly, the more we grow and adopt land solely for human populations; use pesticides to increase immediate crop yield; the more we remove natural ecosystems that currently act with our food production cycles.
    - mythrwy 9y ago
      Grains aren't pollinated by insects though. And domestic bees are brought in hives to many crops that are.
ChuckMcM 9y ago
http://pages.stern.nyu.edu/~dbackus/BCH/demography/Keilman_JDR_98.pdf http://pages.stern.nyu.edu/~dbackus/BCH/demography/Keilman_J... is a paper on how the UN computes these numbers and their relative accuracy. The challenge with extrapolating is that you can't know what you don't know (for example in 1975 they didn't know about AIDs) and you can't know how a society will respond (like Japan going negative in population growth).
Aron 9y ago
disaggregation is the key in everything. If 90% of the world decelerates at -1% a year but 10% accelerates at 10%, then for a few years it looks pretty close to flatline but the extrapolation of that is garbage. You have to have exact factor analysis.
thaumasiotes 9y ago
Peaking above 11 billion necessarily entails also peaking above 9 billion...
- xelxebar 9y ago
  Ahhh... The delicious taste of technically correct. I actually find 11 gigahumans surprisingly low. Unbounded exponential growth would suggest something more like 30 or 40 billion. Clearly that can't go on forever, but exactly what effects are expected to dampen the current post-Industrial trend and why in the 21st century?
  - riffraff 9y ago
    Wealthy people don't have many kids, as the average income goes up the number of kids per family goes down. Population has stopped growing in rich countries years ago, it is expected to happen in currently low income places too.
  - leipert 9y ago
    I highly recommend by the late Hans Rosling: Why the world population won’t exceed 11 billion. It explains quite well what the sister comment by riffraff refers to. [1]: https://www.youtube.com/watch?v=2LyzBoHo5EI https://www.youtube.com/watch?v=2LyzBoHo5EI
  - brango 9y ago
    Access to better healthcare lowers the infant mortality rate. That than leads to couples having fewer children since they don't need to hedge their bets as much (ie having a more offspring expecting several to die). Combine that with easier access to contraceptives and you have some major reasons why birth rates decrease in developing countries which have the money to spend on healthcare. In developed countries you may also have factors like people focussing on careers, valuing independence, more choice in relationships (i.e. divorce/separation being more acceptable) etc.

by xefer 9y ago

mac01021 9y ago

> 11.2 billion and still climbing by 2100. They really don't think any physical constraints are going to get in the way of that? There are only so many fish in the ocean.

xefer 9y ago
The biggest natural constraint was nitrogen fixation which places a natural limit of around 4 billion people. But artificial fertilizers basically took the lid of that and the population has been exploding since been the process was first industrialized. https://pdfs.semanticscholar.org/9ef1/254c1b7626ae1c70f0718c0f811d11d990da.pdf https://pdfs.semanticscholar.org/9ef1/254c1b7626ae1c70f0718c...
WalterBright 9y ago
By then people will probably be mostly eating food created by an industrial process.
nl 9y ago
The short answer is that there are no real physical constraints. BUT there are some fairly important practical issues around unequal access to resources: some places have too much water and some don't have enough. Those kind of problems may lead to war, but probably won't stop population growth (short of it going large-scale nuclear or biological).
- oblio 9y ago
  Population growth in many regions has already plateaued. At least the natural change. Europe, North America, Russia, China, Japan. The main outliers right now are India and Africa. But even those are expected to cool off after their initial burst. The true constraint is administrative capacity: will these countries be able to grow their infrastructure and improve their resource management before they turn their countries into deserts? India will probably manage to, but some African countries probably won't. It's going to be quite bad for some unfortunate people living in these countries...
  - pbhjpbhj 9y ago
    When countries packed with people grow resource scarce then the richer nations either share their resources, commit genocide by starvation, or go to war to keep the resources they have. We can pack in more people but not if we hope to raise the living conditions of all those people. IMO those billions more are mainly going to be living hand-to-mouth in shanty towns. Whole countries living like that have little to lose by going to war to gain resources ...
jwfxpr 9y ago
To be fair, it makes no predictions that the global population of fish will be >0 in 2100.
ars 9y ago
> They really don't think any physical constraints are going to get in the way of that? With enough energy you are not constrained by resource limitations. For example irrigate the desert with desalinated water. It's a really big planet, you could fit a lot of people on it - and animals as well. It's all about energy.
- pbhjpbhj 9y ago
  Hmm, heard about the plummeting insect populations? Artificial pollination is possible but costly, the more we grow and adopt land solely for human populations; use pesticides to increase immediate crop yield; the more we remove natural ecosystems that currently act with our food production cycles.
  - mythrwy 9y ago
    Grains aren't pollinated by insects though. And domestic bees are brought in hives to many crops that are.

ChuckMcM 9y ago

http://pages.stern.nyu.edu/~dbackus/BCH/demography/Keilman_JDR_98.pdf http://pages.stern.nyu.edu/~dbackus/BCH/demography/Keilman_J... is a paper on how the UN computes these numbers and their relative accuracy. The challenge with extrapolating is that you can't know what you don't know (for example in 1975 they didn't know about AIDs) and you can't know how a society will respond (like Japan going negative in population growth).

Aron 9y ago

disaggregation is the key in everything. If 90% of the world decelerates at -1% a year but 10% accelerates at 10%, then for a few years it looks pretty close to flatline but the extrapolation of that is garbage. You have to have exact factor analysis.

thaumasiotes 9y ago

Peaking above 11 billion necessarily entails also peaking above 9 billion...

xelxebar 9y ago
Ahhh... The delicious taste of technically correct. I actually find 11 gigahumans surprisingly low. Unbounded exponential growth would suggest something more like 30 or 40 billion. Clearly that can't go on forever, but exactly what effects are expected to dampen the current post-Industrial trend and why in the 21st century?
- riffraff 9y ago
  Wealthy people don't have many kids, as the average income goes up the number of kids per family goes down. Population has stopped growing in rich countries years ago, it is expected to happen in currently low income places too.
- leipert 9y ago
  I highly recommend by the late Hans Rosling: Why the world population won’t exceed 11 billion. It explains quite well what the sister comment by riffraff refers to. [1]: https://www.youtube.com/watch?v=2LyzBoHo5EI https://www.youtube.com/watch?v=2LyzBoHo5EI
- brango 9y ago
  Access to better healthcare lowers the infant mortality rate. That than leads to couples having fewer children since they don't need to hedge their bets as much (ie having a more offspring expecting several to die). Combine that with easier access to contraceptives and you have some major reasons why birth rates decrease in developing countries which have the money to spend on healthcare. In developed countries you may also have factors like people focussing on careers, valuing independence, more choice in relationships (i.e. divorce/separation being more acceptable) etc.