|IFA Environment Chairman Paul O’Brien said last week’s IPCC report clearly confirms that biogenic methane from cattle should be accounted for differently as it only stays in the atmosphere for a relatively short period of time.
“This is hugely significant and must be factored into the upcoming climate budgets and sectoral targets,” he said. “It would be a total nonsense to make decisions based on a metric that is about to be changed fundamentally."
The IPCC report shows that expressing methane emissions from cattle as CO₂ equivalent emissions overstates the effect of methane emissions on global warming, when they are in equilibrium, by a factor of 3-4 over a 20-year time horizon, while it underestimates the impact of new methane sources.
He said using CO₂ equivalent metrics are reliable measurements for gases that last hundreds or thousands of years such as carbon dioxide, but it does not work for methane that lasts for approximately 10 years.
The IPCC report states that the new emission metric approaches, such as Combined Global Temperature Change Potential (CGTP) and Global Warming Potential (GWP), give a better account for the different physical behaviours of short and long-lived gases.
“The clear acknowledgment of this by the IPCC is a game changer and it must be reflected in policy formulation and how we account for methane emissions in Ireland,” he said.