Malthus revisited, again

Melvyn Bragg’s In Our Time on BBC Radio 4 is unfailingly interesting. Even sub-par episodes are head and shoulders above most other discussion programmes. This week’s episode, on Malthusianism, was no exception, being full of insights into the background and context of Malthus’ famous Essay on the Principle of Population. I learned much, not least that I could probably call myself a Physiocrat and get away with it. ¹

The programme title -- Malthusianism, rather than Malthus -- should have alerted me to the likelihood that there would not be too much discussion about the fundamental premise, that population growth, unchecked, will always outstrip growth in the food supply. This, to me, is axiomatic. One of the participants said that Malthus’ numerical analyses were “not correct,” but I frankly do not see how anyone can dispute the conclusion that geometric growth, compound interest, if you will, must necessarily outstrip arithmetic growth, the simple interest represented by bringing more land into cultivation.

Of course it was Malthus’ misfortune to be making this crucial point just as the scientific approach started to increase the productivity of land per hectare, and we have seen something approaching geometric increases in the food supply as a result. But the amount of sunshine falling on the Earth represents a fundamental limit to agricultural productivity, and hence the food supply, unless we’re somehow all going to be fed on sulphur-reducing tube worms and the like.

The modern-day optimists who cry “Malthus was wrong” do not understand that Nature does truly set limits. And I believe we are bumping up against them.

Of course, Melvyn doesn’t usually do argument on In Our Time, and his guests are invariably pretty clubable, but this is a case where I think it might have been a good idea to have an ecologist, or even an economist on hand to explore this other aspect of Malthusianism. Most of the comments about the programme (self-selected, I know) seem to say the same thing. So maybe we can look forward to a more substantive discussion of food security, agricultural productivity, and international aid and the culture of dependency. And Physiocracy.