Collaboration aims to clear up on-farm carbon confusion

The three major farm carbon calculators have signed a memorandum of understanding (MOU) in a bid to harmonise the methodologies used in calculating the greenhouse gas emissions from agriculture.

The Farm Carbon Toolkit, Cool Farm Alliance Community Interest Company and Agrecalc have said they will “work together to support UK agriculture to measure GHG emissions using the most up-to-date and accurate tools possible, harmonising the methodologies and outputs of their carbon calculation tools”.

The MOU follows Defra research in 2023 that found a “high level of divergence” in results from six farm carbon calculators, including the three now collaborating. Eggbase’s carbon footprint tool, Trinity AgTech’s natural capital calculator and Solagro’s farm calculator were also used to calculate the emissions on 20 models farms. 

The results showed that for seven on the 20 farms, the highest emissions were more than twice as high as the lowest emissions. On poultry farms for example the highest emission outputs were more than 350% of the lowest (where 100% means they show the same emissions). The emissions associated with feed were particularly inconsistent. On livestock farms it was manure management, feed and enteric emissions that varied most from tool to tool.

There was less variation in the emissions calculated at dairy farm, with the highest footprints ranging from 123% to 143% of the lowest. But again, the relative contribution of individual emission sources “could be quite variable” between the research team noted.

To make matters more confusing, there was not one calculator that consistently gave the highest or lowest emissions. “The current level of divergence in carbon assessment between calculators can be extensive,” the researchers concluded. 

Greater granularity of data is needed, they said. Industry and the government must also work on clear definitions of what farm-level assessment of GHGs looks like, what is included and what’s not. Guidelines to help harmonise the calculators would also help considerably.

The new collaboration between the three carbon measurement companies is designed to address some of the recommendations within the Defra report. They aim to for example agree on a common set of data sources that all three calculators will use.

“We are not seeking to reach a point where all three calculators will produce the same answer for any given dataset,” said Liz Bowles, chief executive officer at the Farm carbon Toolkit. “Rather we are striving to make it possible for users to fully understand why different calculators produce different answers.”

The plan is to align with the Science-Based Targets initiative Forestry Land and Agriculture Guidance (SBTi FLAG) and draft Greenhouse Gas Protocol Land Sector Removals Guidance (GHGp LSRG) through the collaboration. 

Eventually there is an intention to find an “agreed way” to measure GHG emissions from farms that would become a minimum required standard for all calculators to adopt. 

The group said it is open to other calculators joining the coalition “so long as they publicly provide transparency in their calculator methodologies”. A webinar will take place on September 11th to highlight some of the work being done.