Out of the Demographic Trap: Hope for Feeding the World

In Africa and elsewhere, burgeoning population growth threatens to overwhelm already over-stretched food supply systems. But the next agricultural revolution needs to get local — and must start to see rising populations as potentially part of the solution.

I bring good news from Machakos, a rural district of Kenya, a couple of hours drive from Nairobi. Seventy years ago, British colonial scientists dismissed the treeless eroding hillsides of Machakos as “an appalling example” of environmental degradation that they blamed on the “multiplication” of the “natives.” The Akamba had exceeded the carrying capacity of their land and were “rapidly drifting to a state of hopeless and miserable poverty and their land to a parched desert of rocks, stones and sand.”

Since independence in 1963, the Akamba’s population has more than doubled. Meanwhile, farm output has risen tenfold. Yet there are also more trees, and soil erosion is much reduced. The Akamba still use simple farming techniques on their small family plots. But today they are producing so much food that when I visited, they were selling vegetables and milk in Nairobi, mangoes and oranges to the Middle East, avocados to France, and green beans to Britain.

What made the difference? People. They made this transformation by utilising their growing population to dig terraces, capture rainwater, plant trees, raise animals that provide manure, and introduce more labour-intensive but higher-value crops like vegetables. For them, “multiplication” of their numbers has been the solution rather than the problem. They have sprung the demographic trap.

The story of Machakos convinces me that humanity is not done yet — our ingenuity may still save us from succumbing to planetary limits, and we can feed a growing world population.

For most of human existence, the land appeared limitless. Whenever populations grew too large for comfort, societies occupied new land. But by the 1960s, most of the best land was taken and the frontiers were being
pushed up inhospitable mountainsides onto poorer soils, and into the last tropical rainforests.

“The battle to feed all of humanity is over,” Paul Ehrlich famously declared in his 1968 book, The Population Bomb, in which he predicted widespread famine because of overpopulation.

But human ingenuity stepped in. In the past half century, thanks to the “green revolution,” the world has added just 10 per cent to farmland but more than doubled food production.

What next? The world was brought up short in 2008 by soaring food prices on international markets. Politicians were unnerved as food riots broke out in more than a dozen countries. Prospect magazine headlined “The Return of Malthus.” We may now be able to feed nearly 7 billion people. But world population is expected to reach 9 or 10 billion later this century. Can we feed them all?

Pessimists have a point. We are undermining agriculture by damaging water and soils. We use more than half of the world’s river flows each year, mostly to irrigate crops. We are recklessly mining irreplaceable underground water reserves. By some estimates, a third of the world’s fields are losing soil faster than natural processes can create it. And now comes the threat of climate change.

But bleak though the figures are, they are no worse than those in the 1960s. Just as then, they reveal not natural limits but the current limits of our competence, both political and technical. Feeding the world in the 21st century requires doing things dramatically better.

The “green revolution” is still keeping pace with population. The trouble is that consumption of grain is growing faster, driven by the world’s growing appetite for bio-fuels and for meat and dairy products. Of the two billion tonnes of grain grown around the world, less than half is eaten directly by people.