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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.

by Fred Pearce

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 utilizing their growing population to dig terraces, capture rainwater, plant trees, raise animals that provide manure, and introduce more labor-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 percent 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 biofuels and for meat and dairy products. Of the two billion tons of grain grown around the world, less than half is eaten directly by people.

Paradoxically, this is good news, says U.S. demographer Joel Cohen. “We know we can feed 10 billion people, because we are already growing enough — if they have a vegetarian diet.” The real threat is consumption patterns, not “overpopulation.” But at least we know the world can be fed.

A second cause for optimism is that farm yields in most of the world are a small fraction of the potential using existing seeds. Africans typically grow one ton of grain on a hectare, Asians grow three tons and Europeans and North Americans upwards of five tons. Futurologist Jesse Ausubel of Rockefeller University in New York says that “if during the next 50 years or so, the world’s farmers reached the average yield of today’s U.S. corn grower, ten billion could be fed with only half of today’s cropland, while they eat today’s U.S. calories.”

That may be far-fetched. But the flipside of our reckless management of water and soils is that we could do things so much better. Conservation farming has vast potential to protect soils. And simple drip irrigation systems could halve global water use by farmers. It’s not rocket science. It’s just tubes with holes in.

Of course, it is one thing to ensure there is enough food on the global dinner table, but quite another to make sure everyone has a seat at the table. Subsistence farming communities make up the majority of the world’s hungry. It matters little to them whether the global grain warehouses are full if their village granaries are empty.

The next agricultural revolution needs to get local. It needs to help these poor farming communities find ways to manage their own soils better by using livestock to fertilize soils, conserving rainwater in case of drought, breeding and exchanging local crop varieties, and finding natural predators for troublesome pests.

In particular we are talking about Africa. Malthusian thinking holds sway here. Many would agree with British demographic doomster Maurice King of Leeds University, who argues in an editorial he co-authored that “large parts of sub-Saharan Africa are demographically trapped... committed to a future of starvation and slaughter.”

But such pessimism is dangerous. It echoes the Malthusian fatalism that the British used to excuse their inaction during the Irish potato famine a century and a half ago: “nothing to be done... too many people... brought it on themselves... better let the carnage play out.”

More importantly, the idea of overpopulated Africa simply is not true. The continent contains 11 of the world’s 20 least-densely populated nations and only one of the 20 most densely populated. Africa’s problem is bad agriculture, not too many people.

Robert Watson, chair of the UN’s International Assessment of Agricultural Knowledge, Science and Technology for Development, which reported in 2008, says of Africa: “Today’s hunger can be addressed with today’s technology. It’s not a technical challenge, it’s a rural development challenge. Farm yields across the continent can be raised from a typical one ton per hectare to four or five tons.”

It can be done. Good news is not hard to find in Africa. And often — as in Machakos — it is more people, not fewer, that can be the key.

Machakos is certainly not unique. In the highlands of western Kenya, the Luo people showed me how they were replacing their fields of maize with a landscape richer both commercially and ecologically. They had planted woodlands that produced timber, honey, and medicinal trees. I saw napier grass, once regarded as a roadside weed, sold as feed for cattle kept to provide milk and manure.

In West Africa, Dutch geographer Chris Reij has charted a similar revival since the famines of the 1970s. Again, he says, it is labor-intensive management of the land that often holds the key. “The idea that population pressure inevitably leads to increased land degradation is a much repeated myth,” he says. “It does not. Innovation is common in regions where there is high population pressure. This is not surprising. Farmers have to adapt to survive.”

There will be exceptions — distressing situations where farmers are unable to rescue their declining environments, and places where fast-rising populations trigger a dangerous tailspin of decline, and where land disputes, war, and bad government leaves communities incapable of harnessing their human resources. But to suggest that Africa is doomed is a dangerous lie. Demography may help drive communities to crisis, but it does not define how they respond.

And as with Africa, so perhaps with the planet. I bring good news: human ingenuity. Rising populations may bring more mouths to feed, but they also bring more hands to work and brains to think. We are not done yet.

Image of sweet potato planting courtesy of Flickr photographer murkas under the Creative Commons License.

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You should know about Danielle Nierenberg's work, she's co-director of Worldwatch's 'Nourishing the Planet: State of the World 2011' project. Blog.

Posted by: Alice Yaxley on 10 Apr 10

a great article, thank you. It chimes with my experience a couple of years ago doing some research in kenya on agriculture. the challenge is daunting - climate change is already hitting hard - but there is some amazing cutting-edge stuff going on like the use of natural predators in place of pesticides and wetlands water purification systems, as well as the usual rainwater harvesting etc. humans are definitely not done yet

Posted by: joy green on 12 Apr 10

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