Telegraph: 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 …