5 reasons why the world can’t feed 10 billion

Every year, we add 78 million people to the world’s population – equivalent to a new USA every 4 years. Demographers, mathematicians and environmentalists have been warning for years that the world’s population will eventually hit a natural limit. In part one of this series, I looked at five reasons to be optimistic about our chances of feeding a population of 10 billion. In part two, I look at five major challenges.

1)      The climate changes everything
For a select and privileged few countries, a warming climate will do wonders for their agriculture. Greenland’s farmers are already enjoying a growing season that is two weeks longer and 1.3C warmer than it was 50 years ago. They are the exception however. For warmer countries, more heat isn’t such a good thing. Southern Africa as a whole is 1C warmer than 50 years ago, and summer rainfall has declined by 20% (pdf). That’s an observable trend, and the consequences are already being felt.

Climatic change isn’t uniform, and some parts of Africa have warmed faster. The tea-growing highlands of Kericho, Kenya, are now 3.5C warmer. That kind of change is disruptive to agriculture. Rains come later, or not at all, or all at once. Seasons change, and farmers don’t know when to plant any more. Weather is more extreme, meaning more crops are lost to drought, floods, or storms.

And it’s not just Africa, as Russia’s drought last year proved. The Chinese Academy of Agricultural Sciences anticipated a 5-10% fall in grain production by 2030. Britain has followed the driest March for 50 years with what is likely to be the hottest April on record, and it’s too early to tell what this will do for our wheat crop. Will it ripen early for a bumper harvest, or dry out in the fields? An unpredictable climate throws food production up in the air.

2)      Water shortages
Linked to climate change is the issue of water. A changing climate moves rainfall patterns, and produces more extreme weather. But even without climate change to contend with, the world’s agricultural systems have a water problem. The planet has a fixed amount of water circulating its hydrological cycles, so it’s not that we’re running out of water per se. The issue is not the amount of water, but where it is and whether or not it is accessible to us.

For example, huge reserves of fresh water are locked up in glaciers. The glaciers melt into rivers, which are diverted for irrigation. As the earth warms, glaciers are melting faster in summer than they can be topped up by snow in winter. The result is a depleting resource. China’s Urumqi river irrigates thousands of acres across Xianjiang, but the glacier that feeds the river is 1C warmer than in 1962, and has declined by 20%.

More water is locked up in groundwater aquifers. Some of these are replenished by rainfall, but can be pumped for irrigation faster than they are topped up. In drier areas, they are often a vestige of a wetter past, meaning it is a one-time only store. Saudi Arabia is a case in point. Their agriculture has been entirely dependent on an aquifer which is now gone, and the wheat harvest has fallen by two thirds since 2007. The World Bank estimates that 175 million Indians and 130 Chinese are fed from unsustainable aquifer use.

3)      The ground beneath our feet
The plough was one of history’s greatest inventions, paving the way for human settlement and a diversification of employment that allowed art and culture to blossom. We owe a lot to the plough, but it may also play a part in our undoing. Ploughing rips into the soil and tears away the vegetation that keeps it together. Year after year, it reduces the soil’s fertility and leaves it dry and dusty, at which point it can simply blow away.

The US ‘dust bowl’ is the most famous example of widespread erosion, when drought and unsustainable farming devastated the Great Plains States. A similar scenario is brewing in China, where grasslands in the Northwest and Inner Mongolia have been turned over to intensive farming, but it’s a worldwide problem. The first global soil survey in 1991 found that 7.5 million square miles of land had already been degraded, a third of all arable land.

4)      Oil dependency
It is an often-repeated fact that ten units of fossil fuel energy go into our food for every unit of calorific energy we get back. Whether it breaks down quite that neatly I couldn’t say, but our agricultural system is certainly dependent on oil to an extraordinary degree. Tractors plough and combines harvest. Machines spray and irrigate. Grain is dried and processed industrially, and shipped thousands of miles by boat and truck for consumption in a genuinely global marketplace. Oil is needed at every stage, and it is a finite resource.

The amount of oil used in agriculture is falling in some areas. It takes 12 gallons of fuel to produce one tonne of US grain today, against 33 in 1973. But in other areas it is growing. Food consumed in Britain today has travelled 50% further than it did in the 1970s. More and more countries have mechanised their agriculture – delivering higher yields, but accelerating oil depletion and erosion in the process.

It is likely that oil production has already peaked. It has certainly hit a plateau, if not gone into decline. The global food network cannot function without cheap oil, and the oil spike in 2008 demonstrates how closely the price of food is tied to the price of oil.

5)      Protectionism, self-interest and bad politics
At a time of crisis, it would be nice to think that the world would be able to pull together and cooperate. Global food reserves and crisis response mechanisms might have been a good place start. Instead, the food crisis of 2008 prompted a rush to secure food supplies on a unilateral basis, every country for itself.

One particular phenomenon is land leasing, where a country with a shortage of arable land leases large tranches of it from a country with a surplus. Deals have proliferated across Africa, as Middle Eastern and Asian countries have snapped up the rights to agricultural produce across vast estates. Saudi Arabia has leased land in Ethiopia. South Korea has a share of Sudan. Madagascar even considered leasing a river to the Saudis. The details of these deals are often sketchy, and how they will pan out for the host country is yet to be seen. There result could well be situations where a native population is going hungry while the country remains an exporter of food, with obvious implications for political stability.

We know plenty of the things we need to do to improve self sufficiency and grow more food, but we don’t do them because of our self interest. Subsidies are the most obvious, and the most immoral. We know that if we dismantled the US and EU agricultural subsidies, farmers in poorer countries would be able to compete in their own local markets. It is a vital measure for future food production and famine prevention, but every attempt to redress the injustice has been thwarted by lobbyists, on both sides of the Atlantic.


Those are five reasons why it is highly unlikely that the world can support 10 billion people,and there are more reasons besides. I haven’t mentioned peak phosphorus, or the hazards of monoculture and our over-reliance on a very few food crops. But there are also things we can do, as I explained in part one of this two part series.  

I’ve presented both sides here to show that we need an honest, big-picture discussion on our world food system. We can’t cherry pick movements or developments we like, and use them to justify either our optimism or pessimism. We cannot allow either complacency or despair to stop us acting.

Can the world feed 10 billion people? I don’t know. But I know that starvation is a terrible way to die, and that we should do everything within our power to try.


  1. There result could well be situations where a native population is going hungry while the country remains an exporter of food, with obvious implications for political stability.
    Like the Irish potato famine.

  2. Excellent article thanks. The only thing you left out was the dramatic drop in biodiversity that we are experiencing that may make everything worse. Time for some urgent action.

    1. Good point. I only made passing reference to that in the area of monocropping, but of course it’s much bigger than that and we have very little idea how the chips will fall.

  3. We owe a lot to the plough, but it may also play a part in our undoing

    I have been trying to understand why humans have been busy ploughing and digging land for the last 10,000 years. If it really was better overall to use ‘no-dig’, why didn’t this catch on (after all, it would seem much less work..)? At the least, there must be situations and conditions where no-dig works best, and those where it doesn’t.

    Is there an intelligent analysis of this issue anywhere suitable for educating interested laymen like me so we can know what’s really sensible to support (or try ourselves)?

    1. No-dig has been used for centuries in cottage gardens and forest gardening, and it still is. The great advantage of ploughing is that you can turn over a large amount of land to the same crop. There’s no shortcut to growing wheat, for example, in any serious quantity. There are forms of ‘no-till’ farming that are still mechanised however, and those are actually catching on in the US mainstream.

      Intelligent analysis for the layman? Hard to say, as most people aren’t interested in farming techniques. I learned a lot from Masanobu Fukuoka’s ‘one straw revolution’, and I use a book in my own garden by Charles Dowding, ‘Organic gardening: the natural no-dig way’. I also recommend the BBC film ‘a farm for the future’, which you can watch online here.

  4. “Southern Africa as a whole is 1C warmer than 50 years ago, and summer rainfall has declined by 20% (pdf). That’s an observable trend, and the consequences are already being felt.”

    Jeremy, just focussing on your point 1) and southern Africa, the bigger picture is, I think, a little more complex than is implied here. For example, looking at the history of the continent, multi-year droughts are not new, having certainly occurred again and again in the past, and have led to famines and much suffering in the region.

    There is an interesting paper from 2001 by Nash and Endfield, which looks at records of droughts and rainfall in the Kalahari region, as derived from missionary correspondence. The authors state: “The precise nature of the causal mechanisms that generated these patterns of climatic variability are still unclear, but the periods of drought identified for the Kalahari during the 19th century appear to show a strong coincidence with the timing of moderate to strong ENSO events identified in the literature.”

    In the early 1800s, for example, there was a severe drought in southern Africa, which coincided with the “Madhlatule” (“eat what you can, and say nothing”) famine. Cormac Ó Gráda, author of Famine: A Short History describes it thus: ‘People had to guard their crops, “for starving people would eat the green mealies growing there.”’

    Historian Charles Ballard also mentions this drought, writing in 1986:
    “Drought has been cited as a prime catalyst in contributing to significant historical changes, particularly on the African continent. The intervention of climate appears to have had a stressful impact on the northern Nguni people of southeastern Africa in the early nineteenth century. The process of state formation among the various chiefdoms accelerated at a time of severe and prolonged drought. Indeed, climatic stress may have been one of the primary catalysts for the social revolution that produced the Zulu Kingdom under Shaka.

    The chronological focus of this article is on the first three decades of the nineteenth century, which was a period of unusually severe drought and abnormally low rainfall for much of southern and eastern Africa. Recent studies of world climate in the first half of the nineteenth century confirm that “synchronous anomalous conditions occurred in other parts of the world.” Climatic change in southern Africa should thus be considered as part of a much larger pattern of world-wide climatic variation with adverse consequences for agriculture and human health.”

    Also, here’s a link to a website put up by South Africa’s Department of Environmental Affairs, which shows long term temperature graphs for selected urban and rural weather stations. It is particularly interesting to look at the records which go back to the 1880s, e.g. those for Cape Town and Durban. Looking at Durban, for example, (future venue for COP17, of course) and going back to the early 1960s (50 years ago, in other words) there is clearly a warming trend. But the bigger picture, over 120 years, tells a rather different story.

    I suppose what I’m trying to get at here is that droughts and famines are not new to southern Africa, there appears to be a connection with ENSO (thus explaining their periodical nature), and there is more to the temperature record than the recent warming (to me it looks as though Cape Town, Durban, Kimberley and Port Elizabeth were about as warm as now, or even warmer, in the 1930s, for example.) Whether or not temperatures there continue to rise, and whether or not the rise is partially anthropological, history tells us that a lack of rainfall is likely to remain a problem in southern Africa, periodically, over the 21st century as well. Whether or not these dry spells lead to famines, I suggest is down to development. Historically the people in the region have always been vulnerable to these droughts, as they have supported themselves by subsistence agriculture or via a pastoral lifestyle. Solutions? In my view – trade, technology, a modern economy and modern infrastructure.

  5. Thanks for the helpful responses Jeremy. I’ll try and study further when i can manage it.
    And thanks Make Wealth History, which i love for its style, combining a succinct friendly approach with balance challenge and rigour. I’m finding it a valuable resource.

  6. .. and thanks for the link to an uninterrupted version of ‘A Farm for the Future’, which i think deserves a much wider airing.

  7. Jeremy, I watched the video you posted. It promotes permaculture as the answer. Seems promising. However, it also claims that more people will have to be involved in agriculture for this system to work. I just don’t see that trend as realistic. Instead, I’d put my bet on electric powered tractors and vehicles fueled though nuclear energy continuing on the current system.

    1. I wouldn’t bet on electric tractors – there’s no electric battery in the world that can deliver the power of a diesel engine, and as far as I’m aware, there isn’t a single electric tractor in production in the world for that very reason. A more realistic solution is that large farms will grow their own biofuels alongside their cash crops, and keep themselves in diesel.

      I don’t see why it’s unrealistic to have more people involved in agriculture however. We have neglected agriculture in the West, and it’s a declining sector as a result. There’s no reason why that couldn’t be overturned. Cuba is an interesting example. When they lost their oil supplies after the collapse of the Soviet Union, they retrained thousands of people to be farmers. Because they were guaranteed a good wage, people took it up. You could take pride in it. If we made farming a legitimate and viable career choice again, made training available and so on, it could work here too.

      On a micro level, a trend towards more people being involved in growing food is already visible. A third of British households are growing some food of their own, a rising trend, and there are similar figures for the US. Maybe it’s a fad, or maybe it reflects a real desire to connect with our food and with our soil again.

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