Case for organics is not proven suggests government study

There is insufficient evidence to prove that organic agriculture is more environmentally friendly than conventional agriculture, according to a new government-sponsored report.

The Environmental Impact of Food Production study was commissioned by the Department for Environment, Food and Rural Affairs and conducted by Manchester Business School.

It says: "From the data we have identified, organic agriculture poses its own environmental problems in the production of some foods, either in terms of nutrient release to water or in terms of climate change burdens."

Organic milk production in particular had a higher global warming impact per unit of milk produced than conventional milk, it claimed. "Organic milk production appears to require less energy input but much more land than conventional production. While eliminating pesticide use, it also gives rise to higher emissions of greenhouse gases, acid gases and eutrophying substances (those that pollute water with too many nutrients) per unit of milk."

It added: "For organic agriculture to offer an approach to food production that is better than conventional agriculture, yields need to rise and methods need to be developed that reduce releases of nitrogen compounds."

There was also little evidence to support campaigners' claims that local sourcing was always better for the environment than efficient national and international distribution networks, said the report.

For example, while it might seem nonsensical to ship tomatoes from California to the UK, the reduced environmental impact of open field cultivation in the US compared to cultivation in polytunnels or greenhouses in south east England had to be weighed against extra food miles.

Overall, however, the data on the environmental impact of food production was very sketchy, the report concluded. Further analysis of everything from raw material extraction, production, product assembly and distribution to use and recycling and re-use were therefore essential.

The report, published as environment secretary David Miliband suggested there was no conclusive evidence that organic food was better than conventional, was dismissed by The Soil Association.

However, last month its policy director Peter Melchett admitted that organic farming had "similar inputs into the farm as non-organic farming in terms of machinery and some packaging, fuel and electricity use". And it suffered from many of the problems of concentration of production and long distance distribution, he added.