The organic movement was inspired by the mysticism of Rudolf Steiner, who believed in planting according to the phases of the moon, enriching the soil through cowhorns stuffed with entrails, and who taught that chemical fertilisers damage the brain. It is based on the belief that nature knows best and science is dangerous.
The SA has argued that organic farming cannot be judged by scientific criteria because "the current tools of scientific understanding are not sufficiently developed" to measure its virtues. It seizes on any findings, however flimsy, that seem to confirm its claims and dismisses any contradictory evidence as irrelevant, prejudiced or influenced by the biotechnology industry.
It has bitterly denounced the Food Standards Agency, an impartial body set up by government to safeguard our welfare, which refuses to endorse the claims made for organic food. Only in January the agency declared that "on the basis of currentevidence ... organic food is not significantly different in terms of food safety and nutrition from food produced conventionally".
It is claimed that organic food is more natural and that its reliance on natural chemicals makes it safer than food grown with the help of synthetic ones. This is nonsense. There is nothing wholesome about natural chemicals like ricin or aflatoxin or botulinum toxin, or especially dangerous about synthetic chemicals like the sulphonamides, isoniazid that cures TB, or the painkiller paracetamol.
We are told we should eat organic food because pesticide residues harm us. As the FSA has pointed out, there is a disparity between public fears and the facts. Dietary contributions to cardiovascular disease and cancer probably account for more than 100,000 deaths a year; food poisoning for between 50 and 300. There are no known deaths from pesticide residues (or GM foods). A cup of coffee contains natural carcinogens equal to at least a year's worth of carcinogenic synthetic residues in the diet. If people are worried about the effect of pesticides in farming on wildlife or human health, they should promote pesticide-resistant GM crops, which reduce their use.
It is said that organic food tastes better. Yes, if it is fresh. But blind tests have shown fresh organic food tastes no better than fresh food grown conventionally. Furthermore, about 70% of organic food is imported and is not fresh, and since it is imported by air, it is not exactly environmentally friendly.
It is said that organic farming benefits wildlife. True, many people become organic farmers for environmental reasons, and achieve their aim. But studies show that environmental effects depend on the style of management, not the system of farming. In general, integrated farm management achieves the best results. What is most beneficial to birds and wildlife is low-till farming, which is made possible by cultivating GM crops. Organic farmers depend on the plough, which disturbs the ecology of the soil, releases more carbon dioxide, uses more fossil fuel and drives out nesting birds.
Even if most claims made for organic farming could be substantiated, its main disadvantage is its inefficiency. Organic food costs more because average yields are 20-50% lower than those from conventional farms. Its inefficiency is highly relevant to the hungry and the poor.
While there may be food surpluses in some areas, we need to treble food production in the next 50 years to feed 3 billion extra people and meet higher living standards at the same time. We face an increasing shortage of water and of good agricultural land. In many places the only way inefficient organic farmers can feed an expanding population is by cutting down more tropical forest. Every form of technology that increases efficiency in farming will therefore be needed to contribute to the production of more food.
What contribution can organic farming make? In the words of the Indian biologist CJ Prakash, its only contribution to sustainable agriculture will be "to sustain poverty and malnutrition".
· Lord Taverne is chair of Sense About Science, and author of The March of Unreason, to be published in November