Greenhouse gases produced by cow burps are growing at a faster rate than the man-made emissions responsible for global warming, according to the latest research.
Various studies have looked at the affect carbon dioxide produced by humans is having on climate change.
But new research has found cows are just as bad by producing methane, a greenhouse gas with a longer lifetime in the atmosphere and therefore higher global warming potential.
Dr Andy Thorpe, an economist at the University of Portsmouth, found a herd of 200 cows can produce annual emissions of methane roughly equivalent in energy terms to driving a family car more than 100,000 miles (180,000km) on more than four gallons (21,400 litres) of petrol.
He added that while carbon dioxide (CO2) emissions have increased by 31 per cent during the past 250 years, methane has increased by 149 per cent during the same period.
Methane in the atmosphere is believed to be responsible for one fifth of global warming experienced since 1750.
The main producers are domestic animals which emit large amounts of methane as they digest their food and then belch out most of it through their mouths.
Dr Thorpe said three quarters of animal methane emissions came from developing countries due to growing affluence and the "hamburger connection" that encourages countries to keep meat to export to the developing world.
He added: "If anything, methane emissions in the developing world are likely to increase."
The research, published in the journal Climate Change, is likely to reignite the debate over whether eating less meat could help combat climate change - as recommended recently by the UN.
It will also inform the UK government's plans to reduce greenhouse gases by 80 per cent by 2050, including in the agricultural sector.