Reducing methane emissions by just three percent per decade will result in “no more warming” due to the Irish national herd by 2050, the Orchatas agriculture committee will hear tomorrow.
At the TA meeting on the Calculation of Methane Emissions, lead climate scientist, Professor Miles Allen of the University of Oxford, is expected to argue that if an updated method is applied to measure the effects of the greenhouse gas, methane from Irish livestock could be released by 2030. The latter will “decrease rapidly”.
The professor is expected to ask for a separate policy to be established for livestock methane.
It comes as the government is yet to ratify a target to cut emissions in agriculture by the end of July, with discussions underway on the overall proposed 22pc-30pc cut by 2030 landing ground.
In a memorandum to the committee, Prof Allen says: “Ireland is one of the first countries with a substantial agricultural sector to develop an ambitious climate policy, which offers considerable opportunities to become a policy leader.
The standard method used to characterize the climate impact of emissions in terms of “carbon footprint” or ‘CO2-equivalent emissions’ does not actually reflect the impact of human activities on global temperatures.
“It was introduced 30 years ago, long before the need for net zero was recognized, and it was never intended to drive policy in pursuit of such an ambitious temperature target. It has long been seen as a problem for agriculture. I am recognized.”
However, he says, “the error depends on whether emissions are rising, constant or falling”.
“A herd of 10 cows generates about a ton of methane per year,” says Prof. Allen.
“Standard carbon footprint calculations show that this methane is equivalent to 28 tons of CO2 per year, whereas if (like the Irish average) that swarm was created in the last century, it would be equivalent to only eight tons of CO2 Ongoing warming is causing .28% per year, a factor of three to four times less.
“But if just one cow is increased in the herd, that increase alone would result in warming equivalent to an additional 13t of CO2 per year over the next 20 years, and 0.8t of CO2 per year thereafter.
“Conversely, if there is only a three percent reduction in emissions per decade (either by a gradual reduction in headcount, or by adding seaweed to feed, for example) then there is no further warming from that swarm’s methane emissions because The decline effect cancels out the warming effect of ongoing methane emissions.”
