The global methane pledge, led by the US and EU, has been formally launched at the Cop26 climate summit in Glasgow, where countries are under pressure to increase their emissions cuts to avoid dangerous warming beyond 1.5C.
Cutting methane, a powerful but relatively short-lived greenhouse gas which comes from sources including fossil fuel extraction and livestock farming, is seen as making a significant short-term contribution to climate action.
Half of the world’s top 30 methane emitters, including the US, EU, Indonesia, Pakistan, Argentina, Mexico, Nigeria, Iraq, Vietnam and Canada, have joined the pledge.
Speaking at the summit, US President Joe Biden thanked those who have signed the “game-changing commitment”.
“Together we are committing to collectively reduce our methane by 30% by 2030, and I think we could probably go beyond that,” he said.
“Today it’s approaching 100 countries that are signing on. That’s nearly half the global methane emissions… It’s going to make a huge difference.”
Mr Biden said this would not only help fight climate change but also improve health, cut crop losses and reduce pollution.
He added: “One of the most important things we can do in this decisive decade to keep 1.5 degrees is reduce our methane emissions as quickly as possible.
“It’s one of the most potent greenhouse gases there is. It amounts to about half the warming we are experiencing today.”
Agriculture is understood to be responsible for 25% of Scotland’s greenhouse gases and is seen as the greatest contributor worldwide.
Cattle and other ruminants produce huge levels of methane as they break wind with researchers suggesting a change to their feed is necessary to cut emissions.
European Commission president Ursula von der Leyen said she is “proud and happy and grateful that over 80 countries have signed up”.
She added: “Methane is 80 times more global warming than CO2. And today, global methane emissions grow faster than at any time in the past.
“So cutting back on methane emissions is one of the most effective things we can do to reduce near-term global warming and keep 1.5C. It is the lowest hanging fruit.”