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A white paper published by EIT Food North-West and Innovate UK, has highlighted the urgent need for the global livestock sector to agree standardised measurement systems and tools to accurately benchmark greenhouse gas (GHG) emissions from farms.
The report authors, who sought the view of leading scientists and industry experts from across the UK and Ireland, point out that two approaches are commonly used, which can deliver results that “often look very different”.
The first relies on the model developed by the Intergovernmental Panel on Climate Change (IPCC), which focuses on emissions in a given territory such as the UK. In this scenario, emissions associated with, for example, growing of imported feed, are not counted in the UK figures.
The second approach relies on life cycle assessment, where all emissions associated with production of a product are usually included. If soya (which can have a high carbon footprint when associated with deforestation) is offered to livestock, it can make the figures look significantly different.
GWP
The EIT Food report also challenges the Global Warming Potential (GWP) metric, and in particular the GWP100 approach used to assess and report GHG emission data from agriculture (including by the UK Climate Change Committee).
Describing GWP100 as “outdated”, the report authors recommend that “mechanisms to replace it with the more realistic GWP* metric need to be established.”
It is now widely accepted that GWP100 overestimates the global warming potential of methane, a key GHG produced by ruminants which, under the current accounting system, makes up around two-thirds of agriculture emissions in NI.
The alternative GWP* takes into account that methane degrades in the atmosphere over a short timeframe (approximately 12 years), so where ruminant livestock numbers are stable, methane produced now is simply replacing methane released 12 years ago. “GWP* is now regarded by many experts as a better metric,” states the EIT Food report.
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