The calculations, which are based on standard industrial methods of meat production in Japan, did not include the impact of managing farm infrastructure and transporting the meat, so the total environmental load is higher than the study suggests.
Most of the greenhouse gas emissions are in the form of methane released from the animals’ digestive systems, while the acid and fertilising substances come primarily from their waste. Over two-thirds of the energy goes towards producing and transporting the animals’ feed.
Possible interventions, the authors suggest, include better waste management and shortening the interval between calving by one month. This latter measure could reduce the total environmental load by nearly 6 per cent. A Swedish study in 2003 suggested that organic beef, raised on grass rather than concentrated feed, emits 40 per cent less greenhouse gases and consumes 85 per cent less energy.
"Methane emissions from beef cattle are declining, thanks to innovations in feeding practices," says Karen Batra of the National Cattlemen’s Beef Association in Centennial, Colorado. "Everybody is trying to come up with different ways to reduce carbon footprints," says Su Taylor of the Vegetarian Society in the UK: "But one of the easiest things you can do is to stop eating meat."