The Law About Moore’s Law:
Everything is exponential. Until it isn’t.
What are you blaming him for exactly? AFAIK he’s famous for pointing out that (in the then-prevailing and assumedly normal situation where TFR is >2) population increases exponentially, but the food supply does not, leading inevitably to overpopulation, famine and death. His prediction was that population could not keep doubling indefinitely.
I wasn’t blaming him for what he said in his book in 1798. I just mentioned Ehrlich’s predictions in 1968, where he said that within a couple of decades the population would increase so fast that there would vast amounts of starvation. This was wrong, but again it just shows that making good predictions beyond about five years ahead is very difficult. It now appears that Malthus was not very good at making a prediction more than two centuries ahead. This is not a matter of blame. It’s just a note that the farther ahead the time your forecast is for, the more difficult it is to make a forecast. Forecasting is very difficult. Then LSLGuy seemed to say that it would have been difficult for Malthus to make the calculation that “the population would be at least 512 times 800 million now, which is more than 400 billion”. No, it wouldn’t. He could do that multiplication with a pen and paper.
My point was that a simple straight line “doubles every X years” calculation is inherently wrong. Understanding how it is wrong and how to make a better calculation that appropriately accounts for the headwinds that will stop or at least temper unlimited exponential grown is not trivial. The math might have been available then; the statistics were not. The crystal ball to predict things like the Green Revolution definitely were not.
Also, people look at the fact that Malthus’ projections of future trends were wrong, and insist that makes his underlying point wrong: that if the population grows enough it will eventually outgrow food production, at which point mass starvation will happen.
Yes, but Malthus was famously the guy saying population would be limited by the food supply, not the one saying it could keep increasing exponentially indefinitely.
I don’t know if he ever tried to predict future population numbers, but I assume he would have underpredicted, since he couldn’t have known about the green revolution. I don’t understand why people are implying the opposite here.
Nonsense.
You can equally say that if food production grows enough it will eventually outgrow the populations’ ability to eat it all, at which point there will be mass crushing deaths from collapsing mountains of stored quadrotriticale.
Mass bad outcomes happen when there are massive overshoots. And not before.
Oddly enough, something else almost always gives first, leading to much more gradual adaptations.
When the if part of the soliloquy is functionally impossible, the whole thing is meaningless.
So, what? The population can grow past the available food and they won’t starve to death For Reasons? The world doesn’t operate on magic.
I think the point is the population cannot grow past the available food. People stop having babies before they starve to death.
History shows otherwise.
The global population has never outgrown the global food supply.
Because up until fairly recently there never was a “global food supply” to outgrow. That didn’t stop famines from happening.
I have A Modest Proposal for you…
Various famines through history, including in the last century, show otherwise. Food availability can decrease quickly and the increase in population is already there. Until they die from starvation of course.
I’m not convinced there currently is a global food supply that matters. There are local ones. When drought or floods cut production in certain areas I don’t think we can depend on those areas producing amply sharing food.
For those of you who haven’t heard of or read this famous essay, here’s the Wikipedia entry and the whole essay itself:
And in contrary news …
Granted. The fact that there is sometimes a mismatch between the local population and the local food supply is a distribution problem (of both the population and the food). It is not a problem with the birth rate, which is the topic of this thread. The global birth rate and the global food production have been well correlated since forever.
Even with the most granular level regions there are and likely always will be. distribution problems. Some go hungry while some have foie gras. Thinking in terms of global supply vs global demand is a simplification like many thought experiments are.
The thought experiment is basic. To the best knowledge of time population would continue to increase exponentially unless it hit a constraint, and food supply would increase linearly. Given that best knowledge of the time the constraint on population would be food supply insufficiency.
Now as it turned out food supply was able to increase more than linearly, at least for a bit, and population increase has not continued as an exponential function with the advent of birth control and prolonged education delaying the start of family growth. Food supply as the constraint has been true at fairly large populations levels though - famines in the Soviet Union and China for example. Parts of Africa.
None of these famines occur because the places experiencing famine have surpassed the population that the area can support. They occurred due to mismanagement and even intentional neglect (in the cases of the Soviet Union and China) or due to outside factors, like war.
Modern agricultural techniques are more than capable of feeding everyone on the planet many times over; and if we adopt advanced agricultural techniques on a more massive scale, like greenhouses or aquaponics, we could increase that capacity by another order of magnitude.
There was a reality of what food supply was available, inadequate for the population that needed to be fed. Hypothetical what could be if governments were less horrible and reality isn’t what it has been, is, and very likely will be, of what it possibly could be if technologies are perfected, is a nice intellectual exercise. Dreams are fun.
So sure it is theoretically possible for humanity to produce more food, especially if there are productivity advances. Maybe even humans will distribute it to where it is needed. And it is theoretically possible that climate change will cause significant productivity decreases specifically in the parts of the world that are currently having kids at more than replacement rates and that mass famines in those regions will result. It is theoretically possible that there will be no wars of governmental incompetence getting in the way of optimizing future food production. But probably past performance of humanity is a good predictor and there will be.