A better awareness is needed among policymakers of the possibility of changes being made to the internationally recognised system of counting methane emissions, according to US farm emissions expert Professor Frank Mitloehner.

If this possibility is ignored, governments could enact policies to cut stable cattle herds which do not contribute to increased global warming, Professor Mitloehner suggested on Wednesday.

A reworking of this emissions accounting system to reflect the differences between methane and carbon dioxide is a change that he believes will be made, the expert said.

The professor stated that the current GWP100 system does not account for methane having a lifespan of only 12 years in comparison to a 1,000-year spell for carbon dioxide. He put this overestimation at three times the actual warming potential.

An updated GWP* system that better reflects this difference would better account for actual global warming incurred by emitting methane. Mitloehner maintains that this change would comply with the 1990 Kyoto protocol that established GWP.

“I believe in the future it will replace GWP100,” he told vets attending a Cattle Association of Veterinary Ireland conference in Tullamore.

“Until that point, we must make sure that policymakers don’t throw the baby out with the bath water by saying let’s get rid of livestock because we know methane is so potent. It is important for them to understand the nuances we are describing.”

The US academic acknowledged that methane from farms “cannot be ignored” but he stated that stable herds do not contribute to warming beyond current levels. However, this is not the case for expanding herds.

“In other words, a constant source of methane does not add additional warming, a constant source of methane causes constant warming.

“An increasing amount of methane over time would cause an increase in warming, and we see that in the developing world where livestock herds are increasing all the time,” Professor Mitloehner added.