A UK study has for the first time demonstrated in evidence the importance of GWP* for more accurately assessing the climate impact of livestock methane.
The environmental impact of a pasture-based beef system was assessed using an unprecedented range of factors, metrics, assessments and scenarios, including GWP*, which showed a huge effect on results.
When applying GWP*, the study showed that the warming impact of methane emitted by UK livestock could be much less than currently reported.
This supports the long-standing view that current Life Cycle Assessments (LCAs) used to assess the environmental impact of foods are too simplistic.
Critics of this system say it fails to acknowledge distinct nuances within agricultural systems, particularly the characteristics of biogenic methane released by livestock.
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.
However, developed and first made public in 2018 by scientists at the University of Oxford, GWP* is an alternative way of calculating the warming effect of methane.
The greenhouse gas is short-lived unlike CO2, dispersing in the atmosphere after 12 years verses CO2’s 1,000-year half-life.
Its development has gained extensive academic interest, including from the UN's Intergovernmental Panel on Climate Change.
In 2021, the panel announced its intention to review the emerging science, 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.
Responding to the study, AHDB said it could have a significant impact on future recommendations to policy makers and consumers.
AHDB’s livestock science director, Chris Gooderham said: “AHDB welcomes this acknowledgement of GWP* from the scientific community.
"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.
“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.”
Earlier this year, the NFU called for the wider adoption of GWP* following previous studies on its accuracy.
The union said the government needed to make sure that greenhouse gas emissions were calculated "in as accurate a way as possible".
This would, in turn, help farmers to better understand and reduce methane emissions, the NFU explained.
Published in Environmental Research, the new research was undertaken by UK scientists at eight institutions.
