Greater complexity needed when measuring methane from livestock, study finds
22nd September 2023
AHDB has welcomed a pioneering study by UK scientists that demonstrates the need for using multiple metrics, such as GWP*, to accurately assess the climate impact of methane from livestock for better policymaking.
The study, published in Environmental Research, assessed the environmental impact of a pasture-based beef system using a wide range of factors, metrics, assessments and scenarios, including GWP* (Global Warming Potential), which accounts for the faster breakdown of methane over time.
The research supports the long-standing view that current Life Cycle Assessments (LCAs) used to assess the environmental impact of foods are far too simplistic and fail to acknowledge distinct nuances within agricultural systems.
Current LCAs convert the impact of different greenhouse gases (GHGs) into CO2 equivalents using the internationally agreed GWP100 (Global Warming Potential over 100 years), established at the 2015 Paris Agreement, of which the UK is legally bound.
Meanwhile, GWP*, which was developed and first made public in 2018 by scientists at the University of Oxford, is an alternative way of calculating the warming effect of methane, a GHG which is short-lived, dispersing in the atmosphere after 12 years, unlike CO2 that has a half-life of 1,000 years.
AHDB’s Livestock Science and Environment director, Chris Gooderham, commented: “AHDB welcomes this acknowledgement of GWP* from the scientific community, and as an evidence-based organisation, we support emerging scientific debate and discussion to ensure the accurate measurement of our industry’s impact on the climate.
“Early analysis by our experts suggests that when applying the more accurate GWP*, the warming impact of methane emitted by UK livestock could be much less than currently reported, casting serious doubt on the current narrative that UK livestock are causing global warming.”
The development of GWP* has gained extensive academic interest, including from the United Nations’ Intergovernmental Panel on Climate Change, which announced its intention to review the work in 2021, acknowledging that the current methodology in accounting for methane is incorrect.
This most recent study provides significant evidence supporting the adoption of GWP*, as it appears to better reflect the actual warming impact of methane on the climate, which could have a significant impact on future recommendations to policymakers and consumers.