Science in Society Archive

Why sustainable agriculture

The debate over sustainable agriculture has gone beyond the health and environmental benefits that it could bring in place of conventional industrial agriculture. For one thing, conventional industrial agriculture is heavily dependent on oil, which is running out; it is getting increasingly unproductive as the soil is eroded and depleted. Climate change will force us to adopt sustainable, low input agriculture to ameliorate its worst consequences, and to genuinely feed the world.

But in order to get there, important changes have to be made in international agencies and institutions, which have hitherto supported the dominant model of industrial agriculture and policies that work against poor countries, where farmers are also desperately in need of secure land tenure.

This mini-series is a continuation of many articles that have appeared in our magazine, Science in Society since 2002.

  1. Feeding the World under Climate Change
  2. Sustainable Agriculture: Critical Ecological, Social & Economic Issues
  3. Restoring Degraded Soils a Matter of Urgency
  4. Food for Thought

Feeding the World under Climate Change

Industrial agriculture contributes enormously to global warming, it is increasingly unproductive and heavily dependent on oil that's fast running out. Nor can it feed us once climate change really gets going. A very different agriculture is needed, says Edward Goldsmith

Climate change is happening

Climate change is by far and away the most daunting problem that the human species has ever encountered. The Inter-Governmental Panel on Climate Change (IPCC) in its last assessment report expect a temperature change of up to 5.8 degrees within this century. However, the IPCC did not take into account a number of critical factors including the annihilation of our tropical forests and other vegetation. These contain six hundred billion tons of carbon - almost as much as is contained in the atmosphere - much of which is likely to be released into it in the next decades by the increasingly uncontrolled activities of the giant logging companies. The Director General of the United Nations Environment Programme recently stated that only a miracle could save the world's remaining tropical forests. Nor does the IPCC take into account the terrible damage perpetrated on the planet's soils by modern industrial agriculture with its huge machines and arsenal of toxic chemicals. Our planet's soils contain one thousand six hundred billion tonnes of carbon, more than twice as much as is contained in the atmosphere. Much of this will be released in the coming decades; unless there is a rapid switch to sustainable, largely organic, agricultural practices.

The Hadley Centre of the British Meteorological Organisation, by contrast, has taken these and other such factors into account in its more recent models, and concluded that the world's average temperature will increase by up to 8.8 rather than 5.8 degrees this century [1]. Other climatologists who take into account often largely neglected factors are even gloomier [2].

The IPCC says that we can expect a considerable increase in heat waves, storms, floods, and the spread of tropical diseases into temperate areas, impacting on the health of humans, livestock and crops. It also predicts a rise in sea levels up to eighty-eight centimetres this century, which will affect (by seawater intrusion into the soils underlying croplands and by temporary and also permanent flooding) something like 30% of the world's agricultural lands [3]. If the Hadley Centre is right, the implications will be even more horrifying. Melting of the secondary Antarctic, the Arctic, and in particular, the Greenland ice-shields is occurring far more rapidly than was predicted by the IPCC. This will reduce the salinity of the oceans, which in turn would weaken if not divert, oceanic currents such as the Gulf Stream from their present course [4]. And if that continues, it would eventually freeze up areas that at present have a temperate climate, such as Northern Europe (see also "Global warming and then the big freeze", SiS 20).

It is indeed ironic that global warming could lead to local or regional cooling. If this were not bad enough, we must realise that even if we stopped burning fossil fuels tomorrow, our planet would continue to heat up for at least 150 years, on account of the residence time of carbon dioxide, the most important greenhouse gas in the atmosphere, while the oceans will continue to warm up for a thousand years at least. All we can do is take those measures - and very dramatic ones are required to slow down the warming process - so that when our climate eventually stabilises, our planet remains partly, at least, habitable.

Climate change is proceeding faster than predicted. This is becoming apparent, among other things, by the prolonged droughts in many parts of the world. Four years of drought in much of Africa have resulted in thirty to forty million people facing starvation. At the same time, drought in the main bread-baskets of the world: the American corn belt, the Canadian plains, and the Australian wheat belt will seriously reduce cereal exports. The climate in Europe in 2002 was dreadful. Massive floods in Germany are costing at least 13 billion dollars. Terrible storms in northern Italy, with hailstones the size of tennis balls, destroyed crops over a wide area, and drought in southern Europe drastically reduced harvests.

I was driven through endless olive groves in the southern Italian province of Foggia and did not see a single olive on any tree. Climate related disaster have been even more destructive in 2003 and 2004.

All this is the result of no more than 0.7 degree rise in global temperature. What will things be like when we have to grow our food in a world whose average temperature has increased by 2 or 3 degrees, let alone by 5 to 8 degrees as we are told later in this century?

Emissions of nitrous oxide and methane

It is becoming clear that climate change and its different manifestations mentioned above will be the most important constraints on our ability to feed ourselves in the coming decades. We cannot afford to just sit and wait for things to get worse. Instead, we must do everything we can to transform our food production system to help combat global warming and, at the same time, to feed ourselves, in what will almost certainly be far less favourable conditions.

Modern industrial agriculture by its very nature makes and must make a very large contribution to greenhouse gases. Currently it is responsible for 25% of the world's carbon dioxide emissions, 60% of methane gas emissions and 80% of nitrous oxide, all powerful greenhouse gases [5].

Nitrous oxide is generated through the action of denitrifying bacteria in the soil when land is converted to agriculture. When tropical rainforests are converted into a pasture, nitrous oxide emissions increase three-fold. All in all, land conversion is leading to the release of around half a million tonnes a year of nitrogen in the form of nitrous oxide.

Nitrous oxide is up to 310 times more potent than carbon dioxide as a greenhouse gas, according to the European Environment Agency, though fortunately atmospheric concentrations of nitrous oxide are currently less than one-thousandth that of carbon dioxide - 0.31ppm (parts per million) compared with 365 ppm. Nitrogenous fertilisers are another major source of nitrous oxide. Around 70 million tonnes a year of nitrogen are now applied to crops and contributing as much as 10% of the total annual nitrous oxide emissions of 22 million tonnes. With fertiliser applications increasing substantially, especially in developing countries, nitrous oxide emissions from agriculture could double over the next 30 years [6].

In the Netherlands, which has the world's most intensive farming, as much as 580 kilograms per hectare of nitrogen in the form of nitrates or ammonium salts are applied every year as fertiliser, and at least 10% of that nitrogen gets straight back into the atmosphere, either as ammonia or nitrous oxide [6].

The growth of agriculture is also leading to increasing emissions of methane. In the last few decades, there has been a substantial increase in livestock numbers - cattle in particular - largely as the result of converting tropical forests to pasture. Cattle emit large amounts of methane and the destruction of forests to raise cattle is therefore contributing to increased emissions of two of the most important greenhouse gases.

Worldwide, the emissions of methane by livestock amount to some 70 million tonnes. With modern methods of production, cattle are increasingly fed on a high-protein diet, especially when fattened in feedlots. Such cattle emit considerably more methane gas than grass-fed cattle. Even the fertilisation of grasslands with nitrogen fertilisers can both decrease methane uptake by soil bacteria and increase nitrous oxide production, thereby increasing atmospheric concentrations of both these gases [7].

The expansion of rice paddies has also seriously increased methane emissions. Rain-fed rice produces far less methane than inundated rice fertilised with nitrogen fertiliser.

Industrial farming is energy intensive

The most energy-intensive components of modern industrial agriculture are the production of nitrogen fertiliser, farm machinery and pumped irrigation. They account for more than 90% of the total direct and indirect energy used in agriculture and are all essential to it.

Emissions of carbon from burning fossil fuels for agricultural purposes in England and Germany were as much as 0.046 and 0.053 tonnes per hectare, compared with only 0.007 tonnes in non-mechanised agricultural systems, i.e., more than seven times lower [8].

This ties in with the estimate of Pretty and Ball [9], that to produce a tonne of cereals or vegetables by means of modern agriculture requires 6 to 10 times more energy than by using sustainable agricultural methods.

It could be argued that a shift to renewable energy sources such as wind power, wave-power, solar power and fuel cells would avoid having to reduce energy consumption to protect our climate. However, this necessary substitution would take decades; about 50 years according to some estimates.

A radical reduction in gas emissions is needed right now if we are to take on board Hadley Centre's prediction that rising temperatures within thirty years will begin to transform our main sinks for carbon dioxide and methane - forests, oceans and soils - into sources. If that occurs, we shall be caught up in a 'runaway' process, i.e. an unstoppable chain-reaction towards increasing temperatures and climatic instability.

Sustainable agriculture a matter of urgency

We must develop an agricultural system that does not cause these terrible problems, and which on the contrary, helps to revitalise and hence build-up our soil resources. Such an agricultural system would have much in common with those once practiced by our distant ancestors and are still practiced by those communities in the remoter parts of the Third World. They may be "uneconomic" within the context of an aberrant and necessarily short-lived industrial society, but they are the only ones designed to feed local people in a really sustainable manner. Significantly, the most respected authorities on sustainable agriculture, among them Jules Pretty and Miguel Altieri, and there are many others, increasingly use the term "sustainable agriculture" as synonymous with "traditional agriculture".

If traditional agriculture is the solution to feeding people under climate change, one might ask why are governments and international agencies so keen to prevent traditional peoples from practising it anymore and to substitute modern industrial agriculture in its place. The answer is that traditional agriculture is not compatible with the developmental process we are imposing on the people of the Third World, still less with the global economy, and less still with the immediate interests of the transnational corporations that control it all.

That this is so is clear from the following quotes from two World Bank reports. In the first, on the development of Papua New Guinea, the World Bank admits that, "a characteristic of Papua New Guinea's subsistence agriculture is its relative richness". Indeed "over much of the country nature's bounty produces enough to eat with relatively little expenditure of effort" [10]. Why change it then? The answer is clear, "Until enough subsistence farmers have their traditional lifestyles changed by the growth of new consumption wants, this labour constraint may make it difficult to introduce new crops", i.e., those required for large scale production for export.

In the World Bank's iniquitous Berg report, it is nevertheless acknowledged [11] "that smallholders are outstanding managers of their own resources - their land and capital, fertiliser and water". And it is also acknowledged that the dominance of this type of agriculture or 'subsistence production' "presented obstacles to agricultural development. The farmers had to be induced to produce for the market, adopt new crops and undertake new risks".

Industrial agriculture is on the way out

Whether we like it or not, modern industrial agriculture is on the way out. It is proving ever less effective. We are now encountering diminishing returns on fertilisers. The Food and Agricultural Organisation of the United Nations (FAO) admitted in 1997 that wheat yields in both Mexico and the USA had shown no increase in 13 years. In 1999, global wheat production actually fell for the second consecutive year to about 589 million tons, down 2% from 1998. Fertilisers are too expensive and as McKenney puts it [12], "the biological health of soils has been driven into such an impoverished state in the interests of quick, easy fertility, that productivity is now compromised, and fertilisers are less and less effective".

Pesticides too are ever less effective. Weeds, fungi, insects and other potential pests are amazingly adaptable. Five hundred species of insects have already developed genetic resistance to pesticides, as have 150 plant diseases, 133 kinds of weeds and 70 species of fungus. The reaction today is to apply evermore powerful and more expensive poisons, which in the US, cost 8 billion dollars a year, not counting the cost of spreading them on the land [13]. The farmers are losing the battle, the pests are surviving the chemical onslaught but farmers are not. More and more farmers are leaving the land, and the situation will get much worse.

Today we are witnessing the forced introduction of genetically modified crops by international agencies in collusion with national governments, as the result of the massive lobbying by an increasingly powerful biotechnology industry. Genetically modified crops, quite contrary to what we are told, do not increase yields. They require more inputs including more herbicides, whose use they are supposed to reduce significantly, as well as irrigation water. Also, the science on which they are based is seriously flawed. No one knows for sure what will be the unexpected consequences of introducing, by a very rudimentary technique, a specific gene into the genome of a very different creature. Surprises are in store and some could cause serious problems of all sorts [14].

Oil is running out

Another reason why industrial agriculture has had its day, even without climate change, is that it is far too vulnerable to increases in the price of oil; and more so, to shortages in the availability of this fuel.

If three million people starved to death in North Korea in the last few years, it was partly the result of the collapse of the Russian market which absorbed most of its exports, so it could no longer afford to import the vast amount of oil on which its highly mechanised, Soviet inspired, agricultural system had become so totally dependent. Its 'farmers' had simply forgotten how to wield a hoe or push a wheelbarrow.

The UK could have been in a similar plight if the transport strike of 2000 had lasted a few more weeks. In an industrial society, oil is required to transport essential food imports, to build and operate tractors, to produce and use fertilisers and pesticides and process, package and transport food to the supermarkets - a more vulnerable situation is difficult to imagine at the best of times - but it is suicidal today.

It is not just temporary oil shortages associated with temporary jumps in the price of oil that we are destined to face but the steady decline in the availability of this commodity. Consequently, oil is due to become increasingly expensive. The truth is that worldwide oil production will peak within the next four to ten years. Oil discoveries have been very disappointing and much of the oil we are using today was discovered some forty years or so ago. The Caspian Sea area which many people in the oil business expected to contain as much as 200 billion barrels of oil; but according to Colin Campbell [15], one of the world's leading authorities on the oil industry, it is more likely to contain as little as 25 billion barrels and no more than 40 or 50 billion. The world uses 20 billion barrels a year and consumption is increasing at an alarming rate.

Although the US has tried desperately to reduce its dependence on the Middle East and succeeded in doing to a certain extent, alternative sources of oil are drying up more quickly than expected. Iran for instance is unlikely to produce more oil than it requires for its own use in ten or fifteen years. Indeed, in the next twenty years the US will have become more dependent on the Middle East than it is today as oil production of countries like Angola, Nigeria, Venezuela, and Mexico also begin to fall. This explains why the US oil industry, which is now in effect the government of the USA, is so fanatically determined to conquer Iraq. Iraq has 11% of world known reserves, of which only a fraction is exploited, and whose oil is the cheapest in the world. The economic consequences of the coming world oil crisis cannot be over-estimated.


Industrial agriculture contributes a lot to climate change; it is increasingly unproductive and heavily dependent on oil that's fast running out. Our only option is to switch comprehensively to sustainable, low input agriculture, which not only feeds the world, but also ameliorate the worst manifestations of climate change.

Article first published 06/10/04


  1. The Hadley Centre. Modelling Climate Change: 1860-2050. Met Office, February 1995.
  2. Bunyard P. Misreading the models: Danger of underestimating climate change. Special Issue The Ecologist, 1999, 29, No 2, 75.
  3. IPCC. Third Assessment Report. Cambridge University Press, 1995.
  4. Bunyard P. How global warming could cuse northern Europe to freeze. The Ecologist, 1999, 29, No 2, 79-80.
  5. Bunyard P. Industrial agriculture - driving climate change, The Ecologist 1996, 26, No 6, 290-8.
  6. Moser A. et al. Methane and nitrous oxide fluxes in native fertilised and cultivated grassland", Nature 1991, 350.
  7. Tebruegge, F. 2000 "No-tillage visions - protection of soil, water and climate, Institute for Agricultural Engineering", Justus-Liebig University, Giessen, Germany, 2000.
  8. Smith, P, Powlson DS, Glendenning, AJ. and Smith JU. Preliminary estimates of potential carbon migration in European soils through no-till farming. Global Change Biology 1998, 4, 679-85 quoted by Corinne Smith in L'Ecologiste, No 7, Vol 3, June 2002.
  9. Jules Pretty J and Ball A. Agricultural Influences on Carbon Emissions and Sequestration. A Review of Evidence and the Emerging Trading Option. March 2001.
  10. Payer C. The World Bank, A critical analysis. Monthly Review Press, New York, 1982.
  11. Accelerated Development in Sub-Saharan Agriculture. World Bank, Washington, 1981.
  12. McKenney, J. "Artificial Fertility: The Environmental Costs of Industrial Fertilizers" in The Fatal Harvest Reader. The Tragedy of Industrial Agriculture, ed Kimbrell, A, Island Press, Washington, 2002.
  13. Campbell CJ. Oil and troubled waters. In Final Energy Crisis (ed. McKillop A), Pluto Press, London.
  14. Ho MW, Lim LC et al. The Case for a GM-Free Sustainable World, Independent Science Panel Report, I-SIS and TWN, London and Penang, 2003.
  15. G J Campbell GJ. The Caspian chimera. In Final Energy Crisis (ed. McKillop A), Pluto Press, London.

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