Scottish agriculture making ‘positive strides’ towards methane targets, says NFU Scotland
Commenting from COP26 in Glasgow, NFU Scotland’s climate change policy manager Kate Hopper said that Scottish farmers, crofters and growers are “already on their net zero journey.”
In response to the announcement from COP26 that more than 80 countries have signed up to a global methane pledge, agreeing to cut emissions by 30% by the end of the decade, Hopper said that Scottish agriculture has “a key role” in further reducing emissions to meet climate change goals of net zero greenhouse gas emissions by 2045. She explained: “The Scottish beef industry has a greenhouse gas footprint that is half of the world average and has reduced methane emissions by 18% in recent times. The carbon footprint of our milk is one-third lower than the world average.
“Scottish soils, which are grazed by cattle and sheep, hold a staggering 3,000 megatonnes of carbon and Nitrous Oxide emissions from fertilisers, soil cultivation and manure management have fallen by 15% as farmers have moved to more organic methods.”
She explained that, while there is more work to do, the Scottish public “can be reassured that […] Scottish agriculture is on target to meeting its environmental responsibilities”, which includes methane and, more importantly, the way the industry includes methane in its emission calculations.
According to Hopper, in Scotland, agriculture is responsible for 7.5 MtCO 2e of greenhouse gas (GHG) emissions, of which methane accounts for 4.4 MtCO 2e. Methane is a greenhouse gas of concern as it is 28 times more potent in its warming potential than CO2.
She warned that the means in which the impact of GHG is calculated, Global Warming Potential 100 (GWP100), is “outdated and does not consider the natural methane cycle.”
Hopper explained: “Biogenic methane (which comes from cattle) is a flow gas which degrades in the atmosphere into CO2 through a natural cycle, compared to a stock gas (like CO2) which does not. A flow gas stays stagnant because it decreases at the rate that it is emitted. The methane is recycled into atmospheric CO2, which is then used by plants, and in turn ruminants. Because methane is a flow gas it has a half-life of 12 years compared to CO2’s half-life of 50 to 200 years.
“A new methodology to properly take this into account has been proposed by the University of Oxford and is supported by NFU Scotland.”
She explained that using the new system, GWP/GWP-we, to assess the impact of methane emissions is “the first step in understanding the full picture of the impact of ruminants and the steps needed to be taken to reduce the impact of methane in Scotland. This includes the use of genetics, feed management, and efficient finishing of animals for the marketplace, alongside increased carbon sequestration and soil, crop and biodiversity management on farm.”