Don’t count out Malthus

The great demographer and economist Thomas Malthus was 23 years old the last time a British summer was this rain-soaked, which was in 1789. The consequences of excessive rainfall in the late 18th century were predictable. Crops would fail, the harvest would be dismal, food prices would rise and some people would starve. It was no coincidence that the French Revolution broke out the same year.

Nine years after that summer, Malthus published his “Essay on the Principle of Population.” We would do well to reread it today. Malthus’ key insight was simple but devastating. “Population, when unchecked, increases in a geometrical ratio,” he observed. But “subsistence increases only in an arithmetical ratio.” In other words, humanity can increase like the number sequence 1, 2, 4, 8, 16

, whereas our food supply can increase no faster than the number sequence 1, 2, 3, 4, 5

We are, quite simply, much better at reproducing than feeding ourselves.

Malthus concluded that there must be “a strong and constantly operating check on population.” This would take two forms: “misery” and “vice,” by which he meant not only alcohol abuse but also contraception and abortion (he was, after all, an Anglican minister).

I wish I could have a free lunch for every time I’ve heard someone declare “Malthus was wrong.” Superficially, it is true, mankind seems to have broken free of the Malthusian trap. The world’s population has increased by a factor of more than six since Malthus’ time. Yet the global average daily supply of calories consumed has also gone up on a per capita basis, exceeding 2,700 in the 1990s. In France on the eve of the revolution it was just 1,848.

The conventional explanation for this is the succession of revolutions in global agriculture, culminating in the postwar “green revolution” and the current wave of genetically modified crops. Since the 1950s, the area of the world under cultivation has increased by roughly 11%, while yields per hectare (about 2 1/2 acres) have increased by 120%. Yet these statistics don’t disprove Malthus. As he said, food production could increase only at an arithmetical rate, and a chart of world cereal yields since 1960 shows just such a linear progression, from below 1 1/2 metric tons to around 3.

Meanwhile, vice and misery have been operating just as Malthus foresaw. Contraception and abortion have been employed to reduce family sizes. And wars, epidemics, disasters and famines have significantly increased mortality. Together, vice and misery have managed to reduce the rate of population growth from 2.2% annually in the early 1960s to about 1.1% today.

The real question is whether we could now be approaching a new era of misery. The United Nations expects the world’s population to pass the 9 billion mark by 2050. But can world food production keep pace? Plant physiologist Lloyd T. Evans has estimated that “we must reach an average yield of 4 tons per hectare

to support a population of 8 billion.” Yields now are just 3 tons per hectare, and a world of 8 billion people may be less than 20 years away.

Meanwhile, man-made forces are conspiring to put a ceiling on food production. Global warming and the resulting climate change may well be increasing the incidence of extreme weather events, as well as inflicting permanent damage on some farming regions. At the same time, our effort to slow global warming by switching from fossil fuels to biofuels is taking large tracts of land out of food production.

Some people worry about peak oil -- when we reach the peak of petroleum production. I worry about peak grain. World per capita cereal production has already passed its peak -- in the mid-1980s -- not least because of collapsing production in the former Soviet Union and sub-Saharan Africa. Meanwhile, rising incomes in Asia are causing a worldwide surge in food demand.

Already, the symptoms of the coming food shortage are detectable. The International Monetary Fund recorded a 23% rise in world food prices during the last 18 months. Of course, we’re not supposed to notice that prices are going up. In the U.S., the monetary authorities insist that we should focus on the “core” consumer price index, which excludes the cost of food and fuel, and has the annual U.S. inflation rate at just 2.2%. But food inflation is roughly double that.

When I wanted a Philly cheese steak last week, I had to pay through the nose. That’s because cheese inflation is 4%, steak inflation is 6% and bread inflation is 10%. Steak is now 53% dearer than it was 10 years ago.

“The great question is now at issue,” Malthus asked more than 200 years ago, “whether man shall henceforth start forwards with accelerated velocity toward illimitable, and hitherto unconceived improvement, or be condemned to a perpetual oscillation between happiness and misery?”

For a long time, we have deluded ourselves that “illimitable improvement” was attainable. As the world approaches a new era of dearth, misery and its old companion, vice, are set to make a mighty Malthusian comeback.

nferguson@latimescolumnists.com