While climate discussions typically focus on mitigating the prominent greenhouse gas carbon dioxide, attention is shifting to addressing potent methane emissions at a global conference in Geneva this week.
Methane, which is potent but relatively short-lived, is a key target for countries wanting to slash emissions quickly and slow climate change.
That is particularly because large amounts of methane are simply leaking from oil and gas projects into the atmosphere.
Methane emissions from the fossil fuel industry have risen for three consecutive years, according to the International Energy Agency (IEA), hitting near record highs in 2023.
Atmospheric methane (CH4) occurs abundantly in nature and is the primary component of gas fuel.
According to U.N. climate experts, it is the second largest contributor to climate change, accounting for roughly 30% of global warming since pre-industrial levels.
Methane remains in the atmosphere for only about 10 years but has a much more powerful warming impact than carbon dioxide.
Its warming effect is 28 times greater than carbon dioxide over a 100-year timescale (80 times over 20 years).
Exactly how much methane is released in the atmosphere remains subject to "significant uncertainty," according to the IEA, despite progress in the monitoring of emissions through the use of satellites.
Scientists are puzzled by the steady increase of methane in the atmosphere, with concentrations currently over two-and-a-half times greater than pre-industrial levels.
The IEA says around 60% of methane emissions are linked to human activity, and the rest come from natural sources, mainly wetlands.
Agriculture is the biggest culprit, responsible for roughly a quarter of that pollution.
Most are from livestock – cows and sheep release methane during digestion and in their manure – and rice cultivation, where flooded fields create ideal conditions for methane-emitting bacteria.
The energy sector, coal, oil and gas – is the second largest source of human-caused methane, which leaks from gas pipelines and other energy infrastructure or is deliberately released during maintenance procedures.
A study published in the journal Nature in March found that oil and gas projects in six major producing regions of the United States were emitting three times as much methane as the government estimated – losses worth $1 billion.
Discarded household waste also creates large amounts of methane when it decomposes if left to rot in landfills.
The IEA estimates that rapid cuts in methane emissions linked to the fossil fuel sector could prevent warming up to 0.1 degrees Celsius by midcentury.
That might sound modest, but such a reduction would have an impact greater than "immediately taking all cars and trucks in the world off the road," the agency said.
IEA Executive Director Fatih Birol called it "one of the best and most affordable" options for reducing global warming.
It could be achieved by repairing leaky infrastructure and eliminating routine flaring and venting during pipeline maintenance.
This month, the IEA said the fossil fuel industry could avoid about 40% of its methane emissions at no net cost.
"Leakage is far too high in many areas where natural gas is extracted, but some countries, notably Norway, have shown that it is possible to extract and supply natural gas with minimal levels of leakage," Energy Program Director William Gillett at the European Academies Science Advisory Council (EASAC) told Agence France-Presse (AFP).
In agriculture, it is possible to modify animal diets by, for example, adding a compound to improve their health and that of the planet.
For rice fields, changes to water management are the "most promising" way to reduce emissions, according to a report by the U.N.'s Food and Agriculture Organization.
A joint EU-U.S. "Global Methane Pledge" was launched in 2021, aiming to reduce worldwide methane emissions by 30% by 2030, compared to 2020 levels.
Some 150 countries have since signed on, but China, India and Russia are not big emitters.
"To slow down climate change, it will be critical that the most important players who have not joined so far will engage" with the pledge, said Gillett.
The U.S. and China have announced they will include methane in their climate action plans and Beijing has revealed a plan to control its emissions – although without a quantified target.
However, voluntary initiatives lack rigorous measures to hold companies and countries accountable.
