IFA environment chair Paul O’Brien has said that this week’s IPCC report confirms that biogenic methane from cattle should be accounted for differently on the grounds that 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 total nonsense to make decisions based on a metric that is about to be changed fundamentally.”

New methane sources

O'Brien said 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 three to four over a 20-year time horizon, while it underestimates the impact of new methane sources.

He said that using CO2 equivalent metrics are reliable measurements for gases such as carbon dioxide that last hundreds or thousands of years, but it is not accurate for methane that lasts for approximately 10 years in comparison.

New metrics

According to the new IPCC report, new emission metric approaches such as combined global temperature change potential (CGTP) and global warming potential (GWP) give a more accurate account for the different physical behaviours of short- and long-lived gases.

“The clear acknowledgement 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,” O’Brien concluded.

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