The world's top authority in farm animal health announced on Thursday it would launch a study into the role of meat in climate change.

The report, carried out by independent experts, is expected to be published "by the summer," Bernard Vallat, head of the World Organisation for Animal Health, known by its French acronym of OIE, said in Paris.

It is the first time in its nearly 85-year history that the 175-nation OIE is to carry out an environmental investigation.

The agency swaps information about diseases in farm animals and issues recommendations in veterinary scares such as H5N1 avian flu.

The probe coincides with mounting interest in the role of meat-eating in stoking climate change.

Farm animals are significant sources of greenhouse gases, either directly through methane emissions from digestion or indirectly, such as clearing forests for pasture and inputs used in raising cattle.

Vallat, who is the OIE's director general, said there had been a "very strong request" from member-states for the report.

The investigation's scope will be limited, and it will not seek to rival or replicate the work of the UN's global-warming scientists, the Inter-governmental Panel on Climate Change (IPCC), he said.

By some estimates, there will be a 50-percent surge in demand for animal protein by 2020 in order to feed the world's burgeoning population and demands from emerging economies, he said.

"Whatever happens, we are going to have to produce more animals to feed the planet," he told a press conference.

Celebrity vegans such as Paul McCartney are urging consumers to boycott meat as a personal contribution to fighting climate change.

A kilogram (2.2 pounds) of beef causes more greenhouse-gas and other pollution than driving for three hours while leaving all the lights on back home, according to a 2007 study led by Akifumi Ogino of the National Institute of Livestock and Grassland Science in Tsukuba, Japan.