Food crisis was predicted 200 years ago

Why is Malthus back in vogue?
The famously pessimistic 18th century English parson was the first to give scientific weight to the theory that unchecked population growth, combined with dwindling food supplies, would lead to "gigantic inevitable famine" and the extinction of mankind. His doomsday theory has invariably been invoked at times of real or imagined food shortages: from the 1840s Irish potato famine, to the food hyperinflation of the Seventies, to the current global alarm. Amid soaring food prices, riots in Haiti and Cairo and UN warnings that grain production must rise at least 50 per cent by 2030 if global hunger is to be averted, the consensus view that Malthus was wrong is once more being challenged.

When was Malthus’s theory debunked?
Almost as soon as he published An Essay on the Principle of Population in 1798. Malthus argued that while population tends to increase in a geometrical ratio (2,4,8,16), food supplies increase only arithmetically (1,2,3,4). His mistake was to underestimate the Industrial Revolution's impact on agricultural productivity. That, combined with the opening up of the prairies in the New World and the rise of global trade, ensured an overall declining trend in world food prices that has lasted, with the odd blip, for two centuries, despite a sixfold increase in world population. Recent "neo-Malthusians" have been equally wrong-footed. The Club of Rome's 1972 treatise Limits to Growth, predicting mass famine by 2000, failed to anticipate a further "green revolution" in improved seed varieties and fertilisers in the Seventies and Eighties.

So why is food production failing so badly today?
It isn't – yet. Indeed, last year's bumper harvest saw global grain yields rise 5 per cent on the previous year, while rice production grew faster than total consumption. It is record prices, not food shortfalls per se, that have been causing havoc in countries reliant on imports. Wheat is up 150 per cent on the year; rice prices have trebled; maize, soya bean and meat prices are at all-time highs. In Britain, that has meant a nasty shock at the checkout. In poor countries, where a far bigger share of household income goes on food, it means real hardship and the threat of political instability.

What caused prices to soar?
Biofuels are often cited as the culprit – not least because they're a textbook example of the distorting impact of state intervention on food production. Thanks to an annual $7bn in federal subsidies, 25 per cent of the US maize crop will be diverted to ethanol by 2020. In Brazil, the second-largest biofuel producer, vast tracts of land have been given over to sugar-ethanol. Yet the impact of biofuels on food prices is hotly disputed (some experts say they explain 30 per cent of the rise; others no more than three per cent) and other factors are clearly involved. There's the soaring cost of oil (fertiliser prices are up 70 per cent); and there's also the impact of intense speculation. In 2003, institutional funds had just $13bn in invested agricultural commodity indexes; by March 2008, that had mushroomed to $260bn. A lot of analysts argue that food prices are now in bubble territory.

Why are investors piling in?
Many buy the Malthusian argument that an overstretched planet will struggle to cope with a projected population leap from 6.7 billion today to 9.1 billion by 2050. Even if prices correct dramatically – sparked, say, by a drop in the oil price or widespread take-up of "second-generation" biofuels capable of growing on non-arable land – the long-term trend, so the argument goes, points to shortages. And it's not just a question of supply, but of big changes in demand.

What big change in particular?
One thing not even Malthus bargained for was the elasticity of the human stomach, which ensured that even as population levels in developed countries fell, appetites rose. The 850 million people existing in a permanent state of malnourishment have now been overtaken in number by the obese, a trend set to increase as newly prosperous nations embrace Western diets. It takes four times more grain to sustain a meat- and dairy-based diet than one based on cereals, and 15 times more water to produce 1kg of meat than 1kg of grain. Hence the fear that we may hit "peak grain" – even if global population does plateau at 10 billion, as some predict.

So are we running out of land to feed such appetites?
Ecological campaigners claim that climate change, urban sprawl, and the toxic effects of industrial farming have had that effect, and the bald stats seem to support them: the global area under cereal production fell from a peak of 740 million hectares in 1981 to 680 million in 2005. Yet this could equally be taken as a sign of technological triumph, crop yields rising so fast that high-cost farms were driven out of business. The great steppes of Russia, Ukraine and Kazakhstan, for example, hold 13 per cent of the world's arable land, yet their ineffi cient farms produce just six per cent of its grain. Yields could possibly be trebled if high-tech farming techniques were applied, enabling the world to be fed for years to come.

What, then, is the key shortage?
Water. Farming takes up 70 per cent of global water demand, but most water for irrigation is lost through leaks or evaporates: little returns to underground basins. So acute are shortages predicted to be, that Goldman Sachs dubs water "the petroleum for the next century". Some 36 nations now face a "negative water" balance, with China and India (thanks to their intensive production drive) particularly badly hit. In China, two-thirds of water wells are dysfunctional as they no longer reach groundwater levels. Water depletion is also a big problem in the US, as underground aquifers in California and the Midwest continue to be drained by agriculture. That's why many now argue that drought-resistant GM crops are all that stand between us and a Malthusian day of reckoning.

Could "Frankenstein foods" save us?
Green campaigners like Friends of the Earth say that the old model of industrial, energy-intensive farming is dead. But tempting though a future dominated by smallholders using traditional seeds might be, the only realistic way of feeding the planet is to boost production - which is why Monsanto, Bayer and other firms specialising in genetically modified (GM) crops say their time has come. They promise seeds that will double yields, need fewer inputs and tolerate drought or salty water. Even Europe, long a doughty bastion against "Frankenstein foods", seems prepared to convert. EC president Jose Manuel Barroso has urged ministers to "bite the bullet"; Gordon Brown wants to relax rules on importing GM animal feed.

There are big caveats, though. None of these "magic" seeds is available yet; and existing GM crops aren't all they're cracked up to be. In 2006 the US Department of Agriculture declared the yield potential of currently available GM crops to be no better than that of hybrid varieties. But on the plus side, there is no convincing evidence that GM foods harm human health and, if even half the touted benefits of new-generation crops are true, they do have the potential to transform food production. Indeed, if the alternative is hunger, you might argue the move into GM is a moral imperative. ·