Current systems used to calculate greenhouse gas (GHG) emissions by Government are overvaluing the impact of long established or declining methane sources, such as livestock farms.
The accounting method used in farming and other sectors of the economy, known as carbon dioxide equivalent, accentuates the impact of methane four-fold, according to climate change expert, Prof Myles Allen of Oxford University.
Speaking during the NFU Conference session entitled ‘climate change, the challenge of our time,’ he called the 30-year old system outdated and ineffective, and said the method had ‘always been acknowledged in the scientific community as not really being fit for purpose.’
He said: “The standard method multiplies methane emissions by 28 to give your Co2 equivalent emissions. This is a complete misnomer because it does not have an equivalent impact on global temperature.
“We don’t actually need to get methane emissions to net zero for methane to stop causing global warming. If it falls by 10 per cent in 30 years, then methane emissions won’t cause anymore warming.”
A more simple and accurate method would be to multiply this year’s Co2 emissions by 112 and subtract 105 times your methane emissions from 20 years ago, he said.
“If you’ve had a stable herd [of cattle] for 20 years, that means it’s worth only 7 tonnes of Co2 warming equivalent per tonne of methane generated by your herd rather than 28, so you’re being overcharged by a factor of four."
Urging delegates to put pressure on Government to make changes to the system, he added: “It’s not that the methane’s not doing anything at all, but the standard accounting systems we use don’t reflect its actual impact on global temperature.”