Eating less meat and dairy produce will not reduce global warming, a leading air quality expert has said.

Celebrities like Sir Paul McCartney and Gwyneth Paltrow have campaigned for less meat consumption to reduce greenhouse gases.

But air quality expert Frank Mitloehner insists that the notion is fruitless in curbing global warming.

Blaming cows and pigs for climate change is scientifically inaccurate, said Dr Mitloehner, dismissing several reports which he said overstated the role that livestock play in global warming.

Campaigns such as “Meat Free Mondays” and “Less Meat Less Heat” were inconsequential, he added.

Instead he suggested developed countries should reduce use of oil and coal for electricity, heating and vehicle fuels.

Former Beatle Sir Paul, one of the world’s best-known vegetarians, was a driving force behind “Less Meat Less Heat”.

“[Mr] McCartney and others seem to be well-intentioned but not well-schooled in the complex relationships between human activities, animal digestion, food production and atmospheric chemistry,” said Dr Mitloehner, from the University of California.

“Smarter animal farming, not less farming, will equal less heat. Producing less meat and milk will only mean more hunger in poor countries.”

Dr Mitloehner said confusion over livestock’s role in climate change stems from a 2006 United Nations report Livestock’s Long Shadow.

It read: “The livestock sector is a major player, responsible for 18% of greenhouse gas emissions measured in carbon dioxide equivalents. This is a higher share than transport.”

Dr Mitloehner said there was no doubt that livestock is a major producer of methane, one of the greenhouse gases.

But he questioned the methodology of the report, contending that numbers for the livestock sector were calculated differently from those for transport.

In the report, the livestock emissions included gases produced by growing animal feed, animals’ digestive emissions and emissions from processing meat and milk into foods.

But the transport analysis factored in only emissions from fossil fuels burned while driving – and not all other transport-lifecycle related factors.

“This lopsided analysis is a classical apples-and-oranges analogy that truly confused the issue,” added Dr Mitloehner.

The report was presented at annual meeting of the American Chemical Society (ANI) in San Francisco on Monday (22 March).