Brad DeLong gives us this slide:
- Now nearly the whole world is closing in on ZPG
- Projected world peak population: 9B in 2050
- Why the demographic transition?
- Economists say wealth
- Birth control technology?
- Culture–especially female literacy
So I’ve received a fair bit of correspondence denouncing me for saying that we have to do something about climate change. Among the various insults is the claim that I’m just another Malthus — which is interesting.
Leave aside the climate science issues. What very few people realize is that Malthus was right about most of human history — indeed, he was right about roughly 58 out of 60 centuries of civilization: living standards basically did not improve from the era of the first Pharaohs to the age of Louis XIV, because any technological gains were swallowed up by population pressure. We only think Malthus got it wrong because the two centuries he was wrong about were the two centuries that followed the publication of his work.
Conor Clarke gives a different graph:
For pretty much all of human history, population growth constrained growth in real standards of living. (That’s the “Malthusian Trap” above: as standards of living improved, population increased, which put a strain on resources and drove down standards of living, which in turn drove down population growth, rinse & repeat.) The industrial revolution broke this trap, although it’s worth pointing out the fairly obvious fact that this is not true for the entire world — which is why the graph is labeled the “Great Divergence” and not the “Unmitigated Triumph.”
An interesting question about the history of economics is whether (and why) we should continue to assume the kind of rapid growth that has characterized western economies since 1800. It hasn’t been around forever.
Krugman comments on Clarke’s graph:
The two figures actually illustrate slightly different points. What the figure above shows is that over a roughly 3000 year period, during which there was obviously quite a lot of technological progress — iron plows, horse collars, mastering the cultivation of rice, the importation of potatoes into Europe, etc. — living standards basically went nowhere. Why? Because population growth always ate up the gains, pushing living standards back to roughly subsistence.
The figure I used in the previous post helps suggest why: technological change was slow — so slow that by 1600 or so, when England had finally reclaimed its population losses from the Black Death, it found real wages back to more or less 1300 levels again.
And here’s the sense in which Malthus was right: he had a fundamentally valid model of the pre-Industrial Revolution economy, which was one in which technological progress translated into more people, not higher living standards. This homeostasis only broke down when very rapid technological change finally outstripped population pressure for an extended period.
Of course, Malthus’s predictive failure wasn’t accidental. Technological takeoff was the product of a newly inquisitive, empirically-minded, scientific culture — the kind of culture that could produce people like Malthus.
Gabriel Beltrone in Slate
Ezra Klein brings it all back to climate change:
We have, in ways that are pretty wonderful, a post-Malthusian attitude about technology. On some level, we trust that it will rescue us when necessary. We may not be able to predict the form of that rescue in advance. But in recent years, trusting that our knowledge will outpace our problems has been a pretty good bet. This has, I think, bred a certain background level of comfort with climate change. There are plenty who believe it a bad thing, but on some fundamental level, don’t believe that really bad things still happen. We’ll find a way out. We always do. If this were a television program, we’re barely at the first commercial break.
And maybe that will prove true. Maybe the hydrogen breakthrough is just around the bend. There’s no obvious reason to think otherwise. But it’s worth remembering that for most of human history, our problems were at least as big as our brains, and technology rarely intervened to avert calamity. There’s no iron law that human civilization can’t be torn apart by catastrophe. It has happened before, as you can see on the part of the graph coinciding with the Black Death. It will likely happen again. Malthus could still be vindicated. So it’s good to put policies in place that make a breakthrough on energy technology more likely. But it’s probably not a safe idea to put such insufficient policies on carbon emissions in place that our real policy is to hope for an technological breakthrough.
Another Malthus debate has been brewing a bit around the sphere.
I think that Thomas Malthus would have been very much at home in the blogosphere. He weighed in on the issues of the day, bringing careful logical analysis of economic theory to bear on the policy issues that were up for debate. And he was very interested in making the connection between economic principles and real empirical evidence. This is particularly true in his contributions to the debate on the Corn Laws in 1814 and 1815. Malthus authored pamphlets on these issues in 1814 (“Observations on the effects of the corn laws”; link) and 1815 (“Grounds of an opinion on the policy of restricting the importation of foreign corn”; link), and they repay scrutiny today; they are powerful instances of a very smart economist probing the theory and the facts surrounding a complex policy issue. (Here is a nice survey of Malthus’s theories; link.)
The Corn Laws might be thought of as a form of “stimulus package” for the British economy in the early nineteenth century. By setting a high tariff on the import of wheat and other grains, Parliament aimed to protect the agricultural sector and to encourage the expansion of grain production to make Britain more independent from external grain providers. One might also compare the debate to the NAFTA debate or to policy deliberations in the 1960s concerning “import substitution” strategies. Opponents argued that removal of the tariffs would bring down the price of grain, a central component of the wage basket; this would help the poor and would also permit a significant reduction of the wage as well. So the issue divides the interests of land owners, industrialists, and the poor.
Malthus’s position in the two essays is somewhat different. In the first article he promises to lay out the issue dispassionately, dispelling false opinions about what the effects of the proposed policy might be and diving into the advantages and disadvantages of the policy. He writes that “some important considerations have been neglected on both sides of the question, and the effects of the corn laws, and of a rise or fall in the price of corn, on the agriculture and general wealth of the state, have not yet been fully laid before the public.”
So what was the effect of the corn laws on the price of corn, on wages, on the welfare of the poor, and so on? Finding an answer to this question, as well as the answer to what impact poor laws have, and what causes gluts (recessions) drove both Malthus and Ricardo to develop theoretical models that could guide them to the answer and hence to the correct policy prescription. Thus, their analytical contributions to economics were driven primarily by the important social questions of the time.