The Rational Optimist (17 page)

Intensive farming saves nature

Taking all cereal crops together worldwide, in 2005 twice as much grain was produced from the same acreage as in 1968. That intensification has spared land on a vast scale. Consider this extraordinary statistic, calculated by the economist Indur Goklany. If the average yields of 1961 had still prevailed in 1998, then to feed six billion people would have required the ploughing of 7.9 billion acres, instead of the 3.7 billion acres actually ploughed in 1998: an extra area the size of South America minus Chile. And that’s optimistically assuming that yields would have remained at the same level in the newly cultivated land, taken from the rainforests, the swamps and the semi-deserts. If yields had not increased, therefore, rainforests would have been burnt, deserts irrigated, wetlands drained, tidal flats reclaimed, pastures ploughed – to a far greater extent than actually happened. To put it another way, today people farm (i.e., plough, crop or graze) just 38 per cent of the land area of the earth, whereas with 1961 yields they would have to farm 82 per cent to feed today’s population. Intensification has saved 44 per cent of this planet for wilderness. Intensification is the best thing that ever happened – from the environmental perspective. There are now over two billion acres of ‘secondary’ tropical rainforest, regrowing after farmers left for the cities, and it is already almost as rich in biodiversity as primary forest. That is because of intensive farming and urbanisation.

Some argue that the human race already appropriates for itself an unsustainable fraction of the planet’s primary production and that if it uses any more, the ecosystem of the entire globe will collapse. Human beings comprise about 0.5 per cent by weight of the animals on the planet. Yet they beg, borrow and steal for themselves roughly 23 per cent of the entire primary production of land plants (the number is much lower if the oceans are included). This number is known to ecologists as the HANPP – the ‘human appropriation of net primary productivity’. That is to say, of the 650 billion tonnes of carbon potentially absorbed from the air by land plants each year, eighty are harvested, ten are burnt and sixty are prevented from growing by ploughs, streets and goats, leaving 500 to support all the other species.

That may seem to leave some room for growth yet, but is it really practical to expect a planet to go on supporting such a dominant monoculture of one ape? To answer this question, break the numbers down by region. In Siberia and the Amazon perhaps 99 per cent of plant growth supports wildlife rather than people. In much of Africa and central Asia, people reduce the productivity of land even as they appropriate a fifth of the production – an overgrazed scrubland supports fewer goats than it would support antelopes if it were wilderness. In western Europe and eastern Asia, however, people eat nearly half the plant production yet barely reduce the amount left over for other species at all – because they dramatically raise the productivity of the land with fertiliser: the grass meadow near my house, sprinkled with nitrate twice a year, supports a large herd of milking cows, but it is also teeming with worms, leatherjackets, dung flies – and the blackbirds, jackdaws and swallows that eat them. This actually gives great cause for optimism, because it implies that intensifying agriculture throughout Africa and central Asia could feed more people and still support more other species, too. Or, in academic-ese: ‘These findings suggest that, on a global scale, there may be a considerable potential to raise agricultural output without necessarily increasing HANPP.’

Other trends too have made modern farming better for the planet. Now that weeds can be controlled by herbicides rather than ploughing (the main function of a plough is to bury weeds), more and more crops are sown directly into the ground without tilling. This reduces soil erosion, silt run-off and the massacre of innocent small animals of the soil that inevitably attends the ploughing of a field – as flocks of worm-eating seagulls attest. Food processing with preservatives, much despised by greenchic folk, has greatly reduced the amount of food that goes to waste. Even the confinement of chickens, pigs and cattle to indoor barns and batteries, though it troubles the consciences (mine included) of those who care for animal welfare, undoubtedly results in more meat produced from less feed with less pollution and less disease. When bird flu threatened, it was free-range flocks of chickens, not battery farms, that were at greatest risk. Some intensive farming of animals is unacceptably cruel; but some is no worse than some kinds of free-range farming, and its environmental impact is undoubtedly smaller.

Borlaug’s genes, sexually recombined with Haber’s ammonium and Rudolf Diesel’s internal combustion engine, have rearranged sufficient atoms not only to ensure that Malthus was wrong for at least another half-century, but that tigers and toucans can still exist in the wild. So I am going to make an outrageous proposal: that the world could reasonably set a goal of feeding itself to a higher and higher standard throughout the twenty-first century without bringing any new land under the plough, indeed with a gradual reduction in farmland area. Could it be done? In the early 1960s the economist Colin Clark calculated that human beings could in theory sustain themselves on just twenty-seven square metres of land each. His reasoning went like this: an average person needs about 2,500 calories of food per day, equivalent to about 685 grams of grain. Double it for growing a bit of fuel, fibre and some animal protein: 1,370 grams. The maximum rate of photosynthesis on well-watered, rich soils is about 350 grams per square metre per day, but you can knock that down to about fifty for the best that farming is in practice able to achieve over a wide area. So it takes twenty-seven square metres to grow the 1,370 grams a person needs. On this basis and using the yields of the day, Clark calculated in the 1960s that the world could feed thirty-five billion mouths.

Well, let me assume that despite Clark’s conservatism about photosynthesis, this is still wildly optimistic. Let me quadruple his number and assume that earth cannot feed an average human from less than 100 square metres. How close are we to that point? In 2004, the world grew about two billion tonnes of rice, wheat and maize on about half a billion hectares of land: an average yield of four tonnes to the hectare. Those three crops provided about two-thirds of the world’s food, both directly and via beef, chicken and pork – equivalent to feeding four billion people. So a hectare fed about eight people, or about 1,250 square metres each, down from about 4,000 square metres in the 1950s. That is a long way above 100 square metres. In addition, the world cultivated another billion hectares growing other cereals, soybeans, vegetables, cotton and the like (pasture land is not part of this calculation) – that is about 5,000 square metres each. Even if you increase the number of people to nine billion, there is still an enormous amount of room for improvement before we start hitting the limit of agricultural productivity. You could double or quadruple yields and still be nowhere near the maximum practical yields of land, let alone the photosynthetic limit. If we all turned vegetarian, the amount of land we would need would be still less, but if we turned organic, it would be more: we would need extra acres to grow the cows whose manure would fertilise our fields: more precisely, to replace all the industrial nitrogen fertiliser now applied would mean an extra seven billion cattle grazing an extra thirty billion acres of pasture. (You will often hear organic champions extol the virtues of both manure and vegetarianism: notice the contradiction.) But these calculations show that even without vegetarianism, there will be a growing surplus of farmland.

So let’s do it: let’s continue to cut down the area of farmland per person to the point where we can begin to turn the rest over to wilderness.

Running out of land to capture sunlight is not going to be a problem for food production – not since Haber broke the fertiliser bottleneck. Running out of water could well be. Lester Brown points out that India depends heavily on a rapidly depleting aquifer and a slowly drying Ganges to irrigate crops, that salination caused by evaporation of irrigation water is an increasing problem all across the world and that fully 70 per cent of all the world’s water usage is for crop irrigation. But he goes on to admit that the inefficiency of irrigation systems (i.e., the loss to evaporation) is falling fast, especially in China, and that there is already a well-used technique – drip irrigation – that could almost eliminate the problem. Countries like Cyprus, Israel and Jordan are already heavy users of drip irrigation. In other words, the wastefulness of irrigation is a product of the low price of water. Once it is properly priced by markets, water is not only used more frugally, but its very abundance increases through incentives to capture and store it.

This is what it would take to feed nine billion people in 2050: at least a doubling of agricultural production driven by a huge increase in fertiliser use in Africa, the adoption of drip irrigation in Asia and America, the spread of double cropping to many tropical countries, the use of GM crops all across the world to improve yields and reduce pollution, a further shift from feeding cattle with grain to feeding them with soybeans, a continuing relative expansion of fish, chicken and pig farming at the expense of beef and sheep (chickens and fish convert grain into meat three times as efficiently as cattle; pigs are in between) – and a great deal of trade, not just because the mouths and the plants will not be in the same place, but also because trade encourages specialisation in the best-yielding crops for any particular district. If price signals drive the world’s farmers to take these measures it is quite conceivable that in 2050 there will be nine billion people feeding more comfortably than today off a smaller acreage of cropland, releasing large tracts of land for nature reserves. Imagine that: an immense expansion of wilderness throughout the world by 2050. It’s a wonderful goal and one that can only be brought about by further intensification and change, not by retreat and organic subsistence. Indeed, come to think of it, let’s make farming a multi-storey business, with hydroponic drip-irrigation and electric lighting producing food year-round on derelict urban sites linked by conveyor belt directly to supermarkets. Let’s pay for the buildings and the electricity by granting the developer tax breaks for retiring farmland elsewhere into forest, swamp or savannah. It is an uplifting and thrilling ideal.

Should the world decide, as a professor and a chef have both suggested on my radio recently, that countries should largely grow and eat their own food (why countries? Why not continents, or villages, or planets?), then of course a very much higher acreage will be needed. My country happens to be as useless at growing bananas and cotton as Jamaica is at growing wheat and wool. If the world decides, as it crazily started to do in the early 2000s, that it wants to grow its motor fuel in fields rather than extract it from oil wells, then again the acreage under the plough will have to balloon. And good night rainforests. But as long as some sanity prevails, then yes, my grandchildren can both eat well and visit larger and wilder nature reserves than I can. It is a vision I am happy to strive for. Intensive yields are the way to get there.

When human beings were all still hunter-gatherers, each needed about a thousand hectares of land to support him or her. Now – thanks to farming, genetics, oil, machinery and trade – each needs little more than a thousand square metres, a tenth of a hectare. (Whether the oil will last long enough is a different subject and one I tackle later in the book: briefly my answer is that substitutes will be adopted if the price rises high enough.) That is possible only because each square metre is encouraged to grow whatever it is good at growing and global trade distributes the result to ensure that everybody gets a bit of everything. Once again, the theme of specialised production/diversified consumption turns out to be the key to prosperity.

Organic’s wrong call

Politicians can make my prediction fail. Should the world decide to go organic – that is, should farming get its nitrogen from plants and fish rather than direct from the air using factories and fossil fuels – then many of the nine billion will starve and all rainforests will be cut down. Yes, I wrote ‘all’. Organic farming is low-yield, whether you like it or not. The reason for this is simple chemistry. Since organic farming eschews all synthetic fertiliser, it exhausts the mineral nutrients in the soil – especially phosphorus and potassium, but eventually also sulphur, calcium and manganese. It gets round this problem by adding crushed rock or squashed fish to the soil. These have to be mined or netted. Its main problem, though, is nitrogen deficiency, which it can reverse by growing legumes (clover, alfalfa or beans), which fix nitrogen from the air, and either ploughing them into the soil or feeding them to cattle whose manure is then ploughed into the soil. With such help a particular organic plot can match non-organic yields, but only by using extra land elsewhere to grow the legumes and feed the cattle, effectively doubling the area under the plough. Conventional farming, by contrast, gets its nitrogen from what are in effect point sources – factories, which fix it from the air.

Organic farmers also aspire to rely less on fossil fuels, but unless organic food is to be expensive, scarce, dirty and decaying, then it has to be intensively produced, and that means using fuel – in practice, a pound of organic lettuce, grown without synthetic fertilisers or pesticides in California, and containing eighty calories, requires 4,600 fossil-fuel calories to get it to a customer’s plate in a city restaurant: planting, weeding, harvesting, refrigerating, washing, processing and transporting all use fossil fuel. A conventional lettuce requires about 4,800 calories. The difference is trivial.

Yet when a technology came along that promised to make organic farming both competitive and efficient, the organic movement promptly rejected it. That technology was genetic modification, which was first invented in the mid-1980s as a kinder, gentler alternative to ‘mutation breeding’ using gamma rays and carcinogenic chemicals. Did you know that this was the way many crops were produced over the last half-century? That much pasta comes from an irradiated variety of durum wheat? That most Asian pears are grown on irradiated grafts? Or that Golden Promise, a variety of barley especially popular with organic brewers, was first created in an atomic reactor in Britain in the 1950s by massive mutation of its genes followed by selection? By the 1980s, scientists had reached the point where, instead of this random scrambling of the genes of a target plant with unknown result and lots of collateral genetic damage, they could take a known gene, with known function, and inject it into the genome of a plant, where it would do its known job. That gene might come from a different species, so achieving the horizontal transfer of traits between species that happens relatively rarely among plants in nature (though it is common-place among microbes).