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Headmaster's Monday Morning Address
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Jun 9, 2008 - 3:09:12 AM

Thomas Malthus and the threat of population growth

Recent months have seen empty shelves in Caracas, food riots in West Bengal, warnings of hunger in Jamaica, the Philippines and sub-Saharan Africa. Soaring prices for basic foods are beginning to lead to political instability, with governments around the world being forced to step in to try to control the cost of essentials like bread and rice.

What’s going on? How can something as basic as global food shortages happen in a world as sophisticated as ours? Well, like all complex problems it has multiple causes, but it is a rather worrying sign of the times that the English economist, Thomas Malthus, is coming back into fashion. Born in 1766, he died in 1834 and his remains rest not far from here, in Bath Abbey. He is most famous for his 1798 work: "An Essay on the Principle of Population as it affects the Future Improvement of Society". Hardly a catchy title I grant you, but it contains a memorable idea which has come to be known as the ‘Malthusian argument’, which basically states that population tends to grow geometrically whilst agricultural production only grows arithmetically.

For those of you not familiar with the difference between arithmetical and geometrical series, think of it as follows. The following series is arithmetical: 1, 2, 3, 4, 5, 6, etc. The next series is geometrical: 1, 2, 4, 8, 16, 32. If, as Malthus predicted, population rises geometrically and food supplies only arithmetically, we will run out of food.

Much of the last 200 years has suggested that Malthus got it wrong. Throughout the 19^th and 20^th centuries, agricultural development has, on the whole, kept pace with population growth. Of course, there have been many serious famines in this period: one thinks of the nineteenth century famines in Ireland and India, for instance, and the man-made famines of the twentieth century, such as that caused by Mao Tse Tung’s ‘Great Leap Forward’ of the 1950s – a crazy policy of forced industrialisation in China which led instead to a famine in which up to 40 million people starved to death. Yet, despite these horrendous exceptions, by and large, growth of the human population has so far been matched by growth in agricultural productivity. Put simply, the human population has grown very fast, but so has the supply of food.

In recent months, however, food riots have shaken economists’ confidence in the future of food supplies and our ability to feed a world population which is continuing to grow. Even Western governments must have felt a Malthusian shudder of worry that they might, one day, be unable to feed their populations.

Of course, all of this is not just down to the rise in population levels. Many would argue that it has been caused by the rise in the price of oil which on Friday reached $140 a barrel. Most food stuffs depend on oil for fertiliser and distribution, for instance. So as oil prices have doubled, so food prices have also rocketed. But in a sense, this misses the point, since the rise in the price of oil is itself caused, at least in part, by the growth in demand for oil from fast-growing economies with huge populations, such as India and China.

Another factor has been the diversion of resources into the production of biofuels, grown on agricultural land, to replace oil. Governments have been optimistic that biofuels could provide a renewable answer to global warming. Put simplistically, what we have here is a competition between the world’s 800 million motorists, who want to maintain their mobility in a post-oil era, and its 2 billion poorest people, who are simply trying to secure enough food to survive. You might think it is obvious whose interests should prevail here – but global markets don’t always work like that. Last year, US farmers severely distorted the world market for cereals by devoting millions of hectares of land to the production of (highly profitable) ethanol for vehicles, land which had previously been used for food. The effect: supply of maize fell, and the world price rose sharply. By diverting resources from food to bio-fuels, such a policy has probably contributed to the threat of famine.

So, what do we do about it? Well, unless technology comes up with a way to raise global food yields dramatically (and even then, we haven’t even touched on the problem of water), there is only really one solution, and that is to slow the rate of population growth. This will be a major geopolitical issue in this century. The world’s population currently stands at around 6.8 billion and is expected to increase to over 9 billion by 2050. So unless policy-makers of the present and the future act decisively and wisely, and globally, then the famines which were forecast by Thomas Malthus may now, over 200 years since he predicted them, become a curse of the 21^st century.