People should consider eating less meat as a way of combating global warming, says the UN's top climate scientist.
Rajendra Pachauri, who chairs the Intergovernmental Panel on Climate Change (IPCC), will make the call at a speech in London on Monday evening.
UN figures suggest that meat production puts more greenhouse gases into the atmosphere than transport.
"The UN Food and Agriculture Organization (FAO) has estimated that direct emissions from meat production account for about 18% of the world's total greenhouse gas emissions," he told BBC News.
said people should have one meat-free day to cut greenhouse gas emissions.
The economist, who is vegetarian, said diet change was important in reducing environmental problems associated with rearing cattle and other animals.
Dr Rajendra Pachauri, chair of the United Nations Intergovernmental Panel on Climate Change,
His comments are the most controversial advice yet provided by the panel on how individuals can help tackle global warning.