British butchers should sell New Zealand lamb rather than local lamb to combat global warming, a study claims.
The study, by the Consultative Group on International Agricultural Research, has found food production accounts for 29 per cent of man-made greenhouse house gases.
The figure is twice the 14 per cent estimated by the United Nations, and accounts for every aspect of food production and distribution - including growing crops and raising livestock, manufacturing fertiliser, and storing, transporting and refrigerating food.
Feeding the world, the researchers claim, releases up to 17,000 megatonnes of carbon dioxide into the atmosphere annually.
The report, Climate Change and Food Systems, suggested Britain would be better off importing lamb from New Zealand as Kiwi farming methods produce half as much greenhouse gases as those used in Britain.
The full "Climate Change and Food Systems" report is behind a pay wall but the abstract can be read here.
Britain's National Farmers Union representative Nathan Alleyne told the Daily Mail: "I don't think we'd be coming out in support of that measure, but we'd need to read the report before commenting on it."
While New Zealand's farming methods may be better than those used in Britain, the report said growing food for sheep, cows and pigs uses more land and produces more greenhouse gases than producing crops for human consumption.
The report, which was published in the 2012 Annual Review of Environment and Resources, also suggested China could cut emissions with more efficient manufacture of fertilisers.
"The food-related emissions and, conversely, the impacts of climate change on agriculture and the food system, will profoundly alter the way we grow and produce food.
"This will affect different parts of the world in radically different ways, but all regions will have to change their current approach to what they grow and eat," said Sonja Vermeulen, the lead author of Climate Change and Food Security.
A second CGIAR report, Recalibrating Food Production in the Developing World, suggested climate change is going to reduce yields of three of the developing world's largest crops - maize, wheat and rice.
Farmers could be forced to turn to more flood and drought-tolerant crops, such as yam, barley, cowpea, millet, lentils, cassava and bananas, the report said.
"We are coming to terms with the fact that agriculture is a critical player in climate change," Frank Rijsberman, chief executive of CGIAR, said. "Not only are emissions from agriculture much larger than previously estimated, but with weather records being set every month as regional climates adjust and reset, there is an urgent need for research that helps smallholder farmers adapt to the new normal."
Bruce Campbell, who heads the CGIAR research programme on climate change, agriculture and food security, said: "Farmers around the world, especially smallholder farmers in developing countries, need access to the latest science, more resources and advanced technology. This research serves as an urgent call for negotiators at the upcoming United Nations Framework Convention on Climate Change (UNFCCC) in Doha."