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Call for urgent adoption of “dual” greenhouse gas accounting to tackle livestock methane

This approach will help cattle and sheep farmers manage methane outputs better and even provide offsetting opportunities for other industries

11 May 2021, at 3:00pm

Opportunities to create climate cooling by changing management of UK livestock could be lost if the way the UK accounts for its greenhouse gas emissions is not addressed urgently.

In a newly published paper the Commercial Farmers Group (CFG) has called on the four nations of the UK to urgently adopt a dual accounting approach – using two different models side-by-side. It says this approach will help cattle and sheep farmers manage methane outputs better and even provide offsetting opportunities for other industries.

The call comes as a new United Nations report on the potential for methane mitigation is published. While in Europe, tackling emissions from the waste sector could allow the greatest progress, it says curbing emissions from ruminant livestock also presents opportunities – except the potential is hard to measure and estimates fluctuate significantly.

Andrew Loftus, Yorkshire farmer and member of the CFG steering group, says lack of suitable accounting methods only confounds this further. “It means the UK livestock industry cannot access accurate and consistent feedback on the real warming impact of methane emissions and the success of different mitigation efforts.”

He says the commonly used “GWP100” accounting method is reliable at measuring gases which last hundreds or thousands of years and keep accumulating in Earth’s atmosphere, mainly CO2 and nitrous oxide, but it does not work for ‘biogenic’ methane from ruminant livestock.

“This is methane that is belched when the animals digest forage, broken down after only 12 years into water and CO2, then locked back up by pasture and forage crops through photosynthesis – a completely different proposition from, for example, CO2 produced from burning fossil fuels. That’s why we need a different way of measuring methane’s impact,” says Mr Loftus.

The alternative model to address this problem already exists. GWP*, developed at the Oxford Martin School in the University of Oxford, reflects the true warming impact of individual gases – in particular those of short-lived climate pollutants such as methane. It is this model the CFG wants to see officially recognised by the UK governments for accounting purposes alongside GWP100.

Mr Loftus says: “New Zealand has already led the way in adopting GWP* alongside GWP100, but the concept has not yet gained wider traction.

“Everyone we speak to who understands the scientific principles behind greenhouse gas accounting, whether researcher or politician, has acknowledged the superior ability of GWP* to measure actual climate warming – its validity is not questioned. The issue with adoption seems to be inertia and reluctance to move away from the status quo.”

Failing to implement dual accounting could represent a huge missed opportunity for the UK. The UN report concludes that targeted measures such as changes to feed or use of supplements, selective breeding, improved animal health and better manure management offer methane mitigation potential.

With methane emissions from UK livestock largely static or declining for many years – being emitted at the same or lower rate than they are breaking down, any reductions in methane output through such measures could actually produce a cooling effect – provided they can be accurately measured.

Professor Myles Allen of Oxford Martin School at University of Oxford, whose team developed GWP*, has stressed the importance of using the correct measures to achieve the required results. He says that having decided to aim for climate neutrality, there is a simple choice.

“We can define climate neutrality in terms of metric-equivalent emissions… or in terms of warming-equivalent emissions. This should be an open and public discussion, because the implications, particularly for agriculture, are profound.

“Achieving climate neutrality in terms of metric-equivalent emissions could mean eliminating practices, such as ruminant agriculture, that are not actually causing global warming. Warming-equivalent emissions [such as GWP*] resolve this problem,” Professor Allen has stated.

He has also warned that failure to address fossil fuel emissions continues to be the bigger issue which overrides any discussion on how to measure methane. “Fossil fuel emissions are driving up global temperatures by two-tenths of a degree a decade,” he says. “Until we stop doing that, everything else is kind of moot.”

With the UK hosting both the G7 summit in June and COP26 in November, the CFG says the UK has a unique opportunity to lead on meaningful greenhouse gas accounting.

Andrew Loftus adds: “Accurate measurement would unlock new technologies to mitigate warming and balance high quality, home-grown protein production with the complexities of optimising land use and reinstating biodiversity. It would show tremendous leadership if the UK became the first G7 country to implement dual accounting.”

The new briefing can be downloaded from the CFG website.