In floppy hat and leaking gumboots, Rahab Thairu makes an unlikely eco-villain as she strolls through thick mud and grass to her banana and avocado plantations.

She has never owned a car, she walks to work and often reads by candle or torchlight, but in the increasingly bizarre battle over who is to blame for climate change Mrs Thairu and other poor African farmers are in danger of losing their entire livelihood because they export produce by air.

The emotionally charged debate, stoked by Western consumer organisations, runs counter to common sense, at least to farmers in the developing world. World Bank figures show that the average Briton emits 30 times more carbon than a Kenyan.

Mrs Thairu and the other 32 members of the tiny Wangige village farming cooperative use officially approved organic methods, involving compost heaps and dung. “We had never heard of organic farming until they came here and told us what it was called. For us, it is the way our fathers and grandfathers farmed. If they take it away from us now it will be terrible. The local buyers will offer us bad prices because they know we have nowhere else to go,” she told The Times.

Mrs Thairu, a Kikuyu peasant farmer in her late sixties, and the rest of the village some 15 miles outside the Kenyan capital, Nairobi, will lose their livelihood if the Soil Association takes away their right to put an organic label on their produce because of the “food miles”. Charles Kimani, who farms avocados in the village and was unemployed until the demand for organic food hit Kenya about ten years ago, said: “A ban on our export market will be death for us.”

The food miles lobby argues that air-freighting food emits more CO2 than any other method of transport. It says that to fly 1kg of green beans from Nairobi to London takes 4kg of carbon. But Cranfield University has calculated that growing roses in Kenya and flying them to Britain actually saves more carbon than if they were grown in a greenhouse in Britain or the Netherlands, with their high energy costs and need for heating.

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