I suppose it could be argued that the Irish Potato Famine was an example of a Malthusian apocalypse. There was a huge population on small holdings, often on land unsuitable for anything but potatoes.
That was a distribution problem, too, at least partly. Ireland was a net exporter of food to England throughout the famine.
Which illustrates why a Malthusian apocolypse can’t be the end of the world: It doesn’t happen everywhere at the same time. One region of the world becomes overpopulated, and one of two things happen: Either the population eventually settles into a new equilibrium, in which case it wasn’t a Malthusian apocolypse after all, or everyone in that region starves to death or dies fighting over the food or whatever, after which that region is now empty and folks from other regions can move there. The world’s too big a place for everywhere to become overpopulated at once, even with modern transportation technologies: The folks who can afford to travel long distances quickly aren’t the ones who would starve anyway.
Well, lets start from the start. In his 1798 treatise An Essay on the Principle of Population, Malthus said:
This appears to be mathematically unassailable. However, while he would certainly have been right about hunters and gatherers, he neglected one important point that distinguishes hunter/gatherer societies from modern societies:
Modern humans make our own food. We grow it. We raise it. We farm it. We produce it in hundreds of ways.
The error in Malthus’s calculation is that, since humans produce the food that we eat, the food production can go up much more than “in an arithmetical ratio”. This makes the underlying calculations wrong, wrong, wrong for anything but hunter/gatherers.
For example, the population of the earth has doubled in my lifetime, going from three to six billion. This is a clear example of a very rapid geometric increase, just as Malthus said.
But the food supply has more than doubled. The world, both rich and poor, eats better now than they did in 1960.
That’s what happened to the “Malthusian Apocalypse”. It died because of a false claim. Food can in fact increase faster than the population increases, we’ve proven that over the last half century. Malthus was wrong.
Now, several people have pointed out that a planet has a finite carrying capacity. However, this is a red herring. “Running out of arable land”, while an apocalypse, is not a “Malthusian apocalypse”. Malthus said nothing about resource availability, and his apocalypse was not predicated on that question.
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And in those places where it can’t, how do you think people survive? Food and resources are global these days. “Aid” from the western world causes population booms in places that are already populated beyond self-sustainability, which then require more aid, which makes the population grow again, which makes them need more aid . . .
But a linear function can go up faster than an exponential, for a while. If you have a linear equation y = x + 3, that’s going to be greater than the function y = e^x for some low values of x. That doesn’t necessarily mean it’s always going to be greater than e^x for all values of x.
What they predicted has not happened yet. They were wrong about the date, certainly.
Using trends to predict the future is pretty much the best we can do. I mean that in both the positive and negative senses. The mortgage collapse is the perfect example of how trends are not perfect and a single large event can destroy the predictions based on them.
Hey, don’t blame me, blame Malthus.
In fact, your example is not relevant to the real world situation. The food supply 1960-2008 did not go up linearly, any more than the population did. Both doubled in fifty years, in a clearly non linear manner.
The explanation for Malthus’s error is not that, as you point out, linear can sometimes be greater than geometric. This is true, but it is not the reason why Malthus was wrong.
Malthus was wrong because food supply is not limited to a linear increase, as he incorrectly claimed.
w.
Even at the time, Malthus’ theory was by no means universally accepted. However, we tend to forget the non-sexy predictions – armageddon is big, it’s flashy, and it reinforces our mental/societal tendencies toward self-importance.
Without speaking toward the relative merits of our current prediction of apocalypse, you can see the same attitudes. Regardless of the truth and severity of global warming, people tend to gravitate toward believing in the worst prediction, even without examining the totality of the evidence or looking at the underlying assumptions. Before you jump on me for being some sort of Exxon poster child, please understand that I am talking about the status of the debate scientifically vs the popular belief – and disclaiming that there is any uncertainty is just incorrect.
The same thing applies to religious themes – people always think that the end times are upon us, because it goes against our self-centrism to believe that the rapture will actually occur in, say, 249 years, when we are long dead. Sports are not immune either – research shows that a loss early in the season can dramatically lower fan self-esteem, and that these fans tend to overestimate the probability of a terrible season after an early loss. (Though preseason games have little effect!)
Look at the y2k thing for the same sort of panic response and scare tactics. The whole time, people were just as loudly proclaiming that there would be almost no effect from the y2k bug – but boring predictions of no change tend to be ignored.
Add to that the fact that we humans are really terrible at predicting the future, and what you get is a tendency toward big scary doomsday predictions that rely on false assumptions, and later on no one remembers the naysayers. Furthermore, our minds work in such a way that in our quest to be consistent, we often ignore contradictory data once we have committed to a belief – there are thousands of psychology experiments that demonstrate this tendency.
Malthus was completely wrong, which is why his prediction failed. Overpopulation might or might not be a problem at some point in the future, but it’s doubtful we will reach some sort of starvation doomsday, because we are capable of changing our behaviors if needed. Unfortunately, the power of these predictions means we will always have debates clouded by psychological tendencies to cling to farfetched predictions.
Hmmm. We seem to have gotten sidetracked into talking about Malthus, which is entirely my fault, because I used the term “Malthusian apocalypse” to refer to something that only in passing has to do with Malthus, namely the belief that many seemed to have in the 70’s that by now, the world would be insanely overpopulated, food riots, resource wars, etc.
However, I’m also learning a heck of a lot about Malthus as well, so it’s all for the good.
Yeah, and I remember reading an Asimov story (Caves of Steel?). Humanity on Earth was eating reconstituted yeast served in communal cafeterias (to save on wastage and duplication of effort), because global population had reached a staggering six billion people. :rolleyes:
The Western world has beaten Malthus because food production has been booted tremendously-by energy intensive farming, new hybrid plants, and cheap fertilizer (also irrigation from underground aquifers).
All of this is going to stall or crash, beacuse the aquifers in the Western USA are being depleted, energy is now expensive, and the West is entering a cyclical dry phase.
So look for the price of food to rise.
Don’t forget that population is not growing exponentially in most Western countries any more, either. Fertility rates are sub-replacement in a lot of the Western world.
Where is breakeven?
Edit: Nevermind, I found it. Looks to be between 2.1 and 3.3, depending. Someone told me recently that if not for immigration the US would be shrinking, and I felt kind of :dubious:, but if I’m interpreting that map correctly, he was right.
I seem to recall a group that called itself “The Club of Rome”-it was a bunch of academics and business men, who were predicting disaster (due to resource depletion). As with all such forecasts, they never get the whole picture. For example-the oil situation-the end of oil was forecast , based upon the known reserves at that time-in the meantime, large reserves were discovered.
Malthus was right about certain things-for example-why is the population of sub-saharan Africa skyrocketing? There are no big increases in the food supply there, and almost no industrial development.
LOL, yup. SIX BILLION? Why, we’ll be standing in each other’s soup!
2.0 exactly, actually, if you don’t arbitrarily throw out all of the zeros in the data set.
I don’t understand. Are you accounting for deaths before reproduction, people who have multiple generations of living descendents, etc, different countries, etc? Or is it some kind of woosh?
Yes, of course. It’s only when you disregard those that you get any number other than exactly 2. Someone who dies at age six has had zero children, so put the number “0” in that spot in the database.