London - Waste milk creates a carbon footprint equivalent to thousands of car exhausts, according to a study that highlights the environmental costs of inefficient farming and the aggressive marketing of supermarket food.

Scientists have calculated that the 360 000 tons of waste milk that are poured down British drains each year create greenhouse gases equivalent to 100 000 tons of carbon dioxide, which is about the same as that emitted in a year by 20 000 cars.

Figures show that 99 percent of milk that is thrown away by British consumers is designated as “avoidable waste”.

Almost half of this waste is a result of too much being served, with the rest discarded for being sour or past its sell-by date.

The scientists also found that if the developed world cut its poultry consumption to Japanese levels – about half of those in the West – the cut in global greenhouse gas emissions would be equivalent to taking about 10 million cars off the road permanently.

The researchers concluded that reducing food waste and cutting back on meat and dairy produce in favour of vegetables could have a significant impact on the greenhouse gases linked with climate change, specifically nitrous oxide, which is about 300 times more potent than carbon dioxide and whose levels are rising globally as a result of agricultural expansion.

Dr David Reay, of Edinburgh University, who led the study on nitrous oxide published in the journal Nature Climate Change, said: “Nitrous oxide is the major greenhouse gas from agriculture.

“It is the gas you can really reduce in terms of emissions if you can cut down on agricultural waste and increase agricultural efficiency.” - The Independent