The next battle in the fight against global warming must be the fight against methane, said the UN Secretary-General in a speech delivered on 23 June in London during “Climate Action Week”. Why methane? Here are some explanations.
A powerful greenhouse gas
Methane is a powerful greenhouse gas and the second-biggest contributor to global warming, after carbon dioxide (CO₂). It is responsible for around a third of the warming observed since the pre-industrial era.
Concentrations of this gas in the atmosphere are now more than two and a half times higher than they were before the industrial era, largely due to human activities.
Whilst CO₂ remains in the atmosphere for around a hundred years, methane only persists for about a dozen years. Yet its immediate impact on the climate remains devastating.
Over 20 years, methane traps up to 86 times more heat than CO2.
Methane is the main contributor to tropospheric ozone, a powerful greenhouse gas and a harmful air pollutant. Inhaling it is responsible for nearly one million premature deaths worldwide each year.
Where does methane come from?
Methane comes from both natural processes, which account for around 40 per cent of global emissions, and human activities, which account for around 60 per cent. The main natural sources are wetlands, bodies of water and the digestion of herbivorous animals (termites, ruminants).
Most human-induced methane emissions come from three sectors: agriculture, mainly linked to livestock (40 per cent); fossil fuels, such as oil and gas processing (35 per cent); and landfill sites (20 per cent).
Permafrost thaw: an increased risk to the climate
Permafrost is soil that has been permanently frozen for at least two consecutive years, covering a quarter of the Northern Hemisphere, including regions without snow. It is a frozen mixture of soil, rock, ice and organic matter, containing around twice as much carbon as is currently present on Earth.
Thawing permafrost mainly emits CO₂, but releases methane if it thaws in wet conditions. It will lead to an increase in greenhouse gases equivalent to that of a large country, depending on the extent of global warming.
According to the United Nations Environment Programme, permafrost thaw is one of the top 10 emerging environmental concerns.
A global commitment to limit methane emissions
In Paris in 2015, at COP21, participating countries committed to reducing greenhouse gas emissions in order to keep the rise in temperatures below 1.5 degrees by the end of the century, compared with the start of the industrial era. According to the latest forecasts, the 1.5-degree threshold could be reached as early as 2030.
At COP26 in 2021, more than 100 countries signed a global commitment, the Global Methane Pledge, aimed at reducing methane emissions by 30 per cent by 2030.
However, the International Energy Agency notes that methane emissions linked to fossil fuel production did not decrease significantly in 2025. This year saw record global production of oil, gas and coal.
Yet reducing methane emissions could have a rapid impact on the greenhouse effect and limit the rise in temperatures within a few decades.
According to the UN, a rapid reduction in methane emissions from fossil fuels could prevent up to 0.1°C of warming by 2050 – the equivalent of the immediate disappearance of all the world’s cars and lorries.
In order to limit global warming to 1.5°C by 2030, half of the reduction efforts will need to focus on methane emissions from fossil fuels.
MARS system: detecting methane leaks from space
In 2022, the United Nations Environment Programme launched MARS, a satellite monitoring system that detects methane leaks in the oil and gas industry. This technology makes it possible to identify and respond quickly to leaks that would otherwise be invisible and odourless.
Since its launch, the system has sent more than 3,500 alerts across 33 countries. Whilst the proportion of alerts leading to concrete action has risen from 1 per cent to 12 per cent in one year, nearly 90 per cent of MARS alerts are still being ignored.