Methane – The Green Tau

11th November 2025

CO2 is the main GHG but methane is another, particularly potent, GHG. Methane doesn’t last as long in the atmosphere (ten to twelve years compared with hundreds or even thousands of years for carbon dioxide) but its warming effect is greater than that of carbon dioxide – as much as 80% more. (1)

40% of methane emissions are natural; 60% are manmade. Methane levels are now two-and-a-half times greater than pre-industrial levels.

Methane levels are still rising but clearly if emissions were curtailed it would help address the short term impact of climate change and rising temperatures. Frustratingly the IEA reports that “around 40% of today’s methane emissions from fossil fuels could be avoided at no net cost” (2) Methane emissions from fossil fuels can be reduced by reducing flaring and venting and by curtailing leaks! NB Natural gas is 80-95% methane.

To date methane emissions reduction has been via voluntary pledges, which are not tackling the problem. This is something that needs to be addressed during COP30. “ Durwood Zaelke, the president of the Institute for Governance and Sustainable Development, said countries must sign a new global agreement on methane rather than sticking with the non-binding pledge. “With emissions still high, the voluntary pledge is clearly not enough to keep us from passing the fast-approaching tipping points,” he said. “We need a more muscular binding methane agreement.” (3)