The NFU has called for the wider adoption of GWP* - a global warming measurement metric - following studies on its accuracy when measuring the impact of methane.
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.
GWP100 is the accepted metric for measuring greenhouse gases but has been acknowledged to not be as accurate when measuring the temperature response of short-lived emissions, such as methane.
The metric also does not account for its removal from the atmosphere.
One alternative metric, known as GWP*, has been developed by climate change scientists at the University of Oxford and in New Zealand.
The NFU, along with other industry groups, say GWP* provides a more accurate measure of the behaviour of methane in the atmosphere and its net contribution to global warming.
NFU Deputy President Tom Bradshaw reiterated farmers’ commitment to tackling climate change, saying that “urgent action is needed now".
“Government support is needed in order for farmers to access the capital investment they need to implement interventions to reduce methane and other greenhouse gases," he said.
“The NFU will continue to engage with Defra on how methane reductions are recorded, incentivised and valued both by the public and private markets.”
In a letter to the Intergovernmental Panel on Climate Change (IPCC) in 2020, the NFU, along with the National Sheep Association and Beef + Lamb New Zealand, called for the UN to take up the new metric.
Using metrics that 'inaccurately' capture the contribution to warming of short-lived gases could 'lead to poor policy decisions', a statement by the organisations said.
They added that policy advisers needed to reflect solutions that distinguish between the dynamics of biogenic methane and gases that persist in the atmosphere for long periods.
The statement said: "Given the scale of the climate change crisis facing the planet, it is vitally important that the best scientific information and tools available are being used to inform.
"The current measurements in use may not give an accurate reflection of agriculture’s true impact on global warming.
"Therefore the agricultural sector is keen to ensure that the industry is fairly viewed and the positive impact it can have on climate change is highlighted."
What is the NFU asking for?
The union is now asking for:
• A unified approach to dual accounting with government and industry reporting on emissions from agriculture at the national scale using GWP100 and GWP*.
• Solutions for incorporating GWP* into on-farm GHG calculators so individual producers are not disadvantaged for expanding when national herd/flock emissions remain unchanged or are decreasing due to uptake of new tools and technology
• Consistent and simple messaging to consumers on the temperature impacts from methane and the biogenic carbon cycle, including finding a more suitable way for the carbon footprint of a food product to be measured
• The impact of genetics and selective breeding on reducing methane emissions to be measured with GWP100 and GWP*
• A joined up approach to GHGs across government departments, e.g. when looking at air quality under Clean Air Strategy and GHG emissions reductions vs the future of ELMs.
