LONDON (Reuters) - People will have to cut meat from their diets if the world is to stay within safer limits of planet-warming greenhouse gases, nitrate pollution and habitat destruction, according to a report published Monday in the Proceedings of the National Academy of Sciences.
Experts agree that eating plant products can be better for the environment, because eating meat involves consuming animals which are themselves raised on plants, a less efficient process.
But there is some controversy about just how far people should shun meat for vegetables and grains to curb damage to the environment, partly because of wide disagreement about exactly what those impacts are.
The paper used coarse estimates to argue that, on current trends, livestock farming on its own - disregarding all other human activity - would push the world near danger levels for climate change and habitat destruction by mid-century.
"We suggest that reining in growth of this sector should be prioritized," said the authors from Canada's Dalhousie University, in their article titled "Forecasting potential global environmental costs of livestock production 2000-2050."
The paper described "a profound disconnect between the anticipated scale of potential environmental impacts associated with projected livestock production levels and even the most optimistic mitigation strategies."
Solutions to the problem included using best practice such as substituting manure for nitrogen fertilizers, and increasing agricultural productivity, said the paper published
But efficiency gains would not be enough. Per capita meat consumption would have to be cut.
"Across the board reductions in per capita consumption of livestock products should ... be a policy priority," it said.