Blaming farmers for global warming that they aren’t causing seems like a great way to alienate an industry.
his is the view of Myles Allen, professor of Geosystem Science at the University of Oxford, who says the agricultural sector is “desperately needed” in the fight against climate change.
In conversation with the Farming Independent Prof Allen, who served on the UN’s Intergovernmental Panel on Climate Change IPCC (IPCC), frankly responded to questions on how governments are handling the bovine methane conundrum.
Q: How would you describe the current science around the impact of biogenic methane on global warming — is it fairly contested?
MA: “It depends on the source, and whether that source is increasing or decreasing.
“The IPCC 6th Assessment Report summed it up well.
Our current practice of treating methane as ‘CO2-equivalent’ using the ‘GWP100’ exchange rate — which equates 1t of methane with 28t of CO2 — overstates the impact of a constant methane source by a factor of 3-4, while understating the impact of any new methane source by a factor of 4-5 over the 20 years following its introduction.
So, it is impossible to come up with a single number that fairly reflects the impacts on global temperature of both established sources (like old dairy herds) and any change in methane emissions (like a new fracking operation).
Q: How to you think policy-makers and politicians are handling the science on the methane issue?
MA: “The obvious solution is to stop pretending methane and CO2 are ‘equivalent’, accept they both affect global temperature but in fundamentally different ways, and set separate policies for both.
“Policy-makers seem strangely reluctant to do this, although it is the only solution that makes sense scientifically.”
Q: What is your biggest concern about the direction of travel on national/international policies, and narratives, for reducing methane emissions from agriculture?
MA: “Blaming farmers for global warming that they aren’t causing seems like a great way to alienate an industry whose help we desperately need in the fight against climate change.
“As I keep emphasising to environmentalists, this is not a fight they need to pick.”
Q: What is your view on arguments that cutting livestock numbers is the most efficient way to reduce methane emissions from the farm sector?
MA: “Even though an established ruminant herd, or rice paddy field, isn’t causing nearly as much global warming as the conventional carbon footprint calculators suggest it is, its existence provides an opportunity, because cutting methane emissions can actually reduce global temperatures, just like planting trees to take CO2 back out of the atmosphere.
“If farmers were given credit for this, they might take a very different view of the prospect of cutting livestock numbers.”
Q: What message would you give the general public about the current impact of agri emissions on global warming?
MA: “Livestock cuts can make a positive contribution, but we don’t actually need to eliminate livestock farming to stop global warming — while we do need to stop dumping CO2 from fossil fuels into the atmosphere.
“Eliminating methane emissions from global livestock farming entirely would have shave a few hundredths of a degree off global temperatures in 20 years’ time.
“Meanwhile, CO2 from fossil fuels is driving up global temperatures by two-tenths of a degree per decade.
“We have to stop fossil fuels from causing global warming. If we don’t, everything else is pretty much irrelevant.”