This phenomenon is seriously threatening countries' efforts to meet their climate goals, researchers cited by AFP have warned.
"Methane is increasing in relative terms faster than any other major greenhouse gas and is now 2.6 times higher than in pre-industrial times," an international group of researchers under the auspices of the Global Carbon Project said in a study published in Environmental Research Letters.
Methane is the second most abundant greenhouse gas produced by human activity, after carbon dioxide. The main sources are agriculture, energy production and organic waste rotting in landfills.
In the first 20 years, its impact on the atmosphere is about 80 times greater than that of carbon dioxide, but it breaks down faster than CO2.
This opens up the possibility of drastically reducing the climate impact in the short term. However, the researchers found that despite efforts to reduce methane emissions, the concentration of this gas in the atmosphere continues to increase.
In 2000, an average of 6.1 million tonnes of methane were added to the atmosphere annually.
In 2010, this rose to 20.9 million tonnes per year. In 2020, it reaches 41.8 million tonnes.
"Anthropogenic (human-caused) emissions continue to increase in almost all other countries in the world, with the exception of Europe and Australia, which show a slow downward trend," said Global Carbon Project executive director Pep Canadell, one of the study's co-authors.
The biggest increases came from China and Southeast Asia and were mostly linked to coal mining, oil and gas production and landfills, the researchers found.
The La Niña weather phenomenon also led to an increase in methane from natural sources, they said.
The drop in nitrogen oxide pollution in 2020, when vehicle use declined sharply due to the Caulide-19 pandemic, had a paradoxical impact. It is key to preventing the build-up of methane in the atmosphere.
Rising methane pollution is undermining efforts to prevent the Earth's average temperature rising more than 2.0 °C above pre-industrial levels.
In 2021, the European Union and the United States of America launched a "Global Methane Pledge" to reduce global methane emissions by 30% from 2020 levels by the 2030 target date.
More than 150 countries have signed up - but not China, India or Russia.
"Right now, the Global Methane Commitment's goals seem as distant as a desert oasis," explained the lead author of the Environmental Research Letters paper, Stanford University scientist Rob Jackson.
"We all hope they are not a mirage," he added.
China and the United States are preparing to host a summit on non-CO2 greenhouse gases later this year, which could raise the prospect of further commitments from governments. | BGNES
