Methane (CH₄) is a powerful greenhouse gas that attracts far less attention than its big sister, carbon dioxide, also known to everyone by its chemical formula, CO2. To date, there is no global target for CH₄ in the UN climate change negotiations, only a generic, voluntary commitment by 100 nations to reduce anthropogenic methane emissions by 30 per cent by 2030. However, according to some recent findings, even this effort to reduce emissions from oil and gas extraction and the agro-food sector may not have the desired impact, since - and this is the worrying news - feedbacks in the climate system (also caused by CO₂ and CH₄ and other human-generated greenhouse gases) are increasing methane emissions from natural sources, particularly from tropical wetlands and in the Arctic.
According to a paper published on 30 July in the scientific journal Frontiers in Science, the effort to stop methane leakage from oil and gas extraction and from landfills and to reduce enterogenic emissions from livestock farms (the pledge is a 30 per cent reduction on a voluntary basis) would be undercut by methane released from permafrost and increased decomposition in wetlands caused by record global average temperatures in recent years and increased rainfall in tropical areas. In addition, actions to reduce anthropogenic CH₄ emissions to reach the -30% methane target also remain sporadic, poorly documented and full of gaps.
The article reads: “atmospheric methane has been rising rapidly since 2006 and by the end of the 2010s reached 5-year average growth rates not seen since the 1980s. Methane concentration increases in 2021 are the largest recorded, with high values throughout the period 2020 to 2023”. There is no escaping it: instead of decreasing, CH₄ is growing ever faster. Not only that: globally, the increase in water vapour caused by global warming is slowing down the rate of methane breakdown in the atmosphere, increasing the amount of time the gas remains in the air.
Therefore, the authors of the article conclude, ‘anthropogenic [CH₄] emissions must fall more than expected to reach a certain warming target,’ i.e. the 2°C considered the safe threshold by climatologists to avoid the most catastrophic effects of climate change. In addition, of course, global carbon dioxide emissions must continue to be reduced.
Why global action on methane is needed
Methane traps about 80 times more heat than carbon dioxide over a 20-year period and scientists estimate that it is responsible for 20-30% of climate warming since the beginning of the industrial age, when atmospheric methane had a concentration of about 0.7 parts per million (ppm). Since then, it has zigzagged upwards, peaking with the first fossil gas boom in the 1980s, then stabilising slightly before a huge surge in the early 2000s. The amount of methane in the atmosphere reached about 1.9 ppm in 2023, almost three times the pre-industrial level. This global warming potential means that removing CH₄ rather than CO₂ would have more rapid and impactful effects in the short term , thus helping in the challenge of decarbonisation. The increase of methane from natural sources should spur even more efforts to cut emissions wherever possible, including from fossil fuel use and agriculture, said lead study author Drew Shindell, an earth scientist at Duke University's Nicholas School of the Environment.
In 2008 during the US fracking boom, particularly in Pennsylvania and Texas, it was common to witness accidents during the process of hydraulically fracturing clay shale to make methane flow. The author of the article witnessed at least two cases in 2009 in Pennsylvania, although at the time there was more concern about water contamination than about fugitive CH₄ emissions. Today, it is clear that the oil & gas sector contributes significantly to anthropogenic emissions of this greenhouse gas. Recent measurements by a specially-equipped jet (MethaneAIR) as well as taken via satellite show that methane emissions from oil and gas operations in the US are more than four times higher than EPA estimates and eight times higher than fossil industry targets.
Agriculture also plays its part (along with landfills, which, however, are always better regulated) by adding fermentation from rice cultivation and enteric emissions from the livestock sector. "If we reduced those we’d see a large decrease in atmospheric concentrations,” said Shindell. “But cutting emissions from agriculture in particular is improbable in the near-term, and maybe even in the long term.” So the primary target remains fugitive emissions of the energy sector. The researchers noted that the costs of reducing methane emissions are low compared to many other climate mitigations, and that “legally binding regulations and widespread pricing are needed” to encourage the deep cuts that are required. as it's already happening in the US, to encourage the required cuts.
A cascading phenomenon
The cold, dry regions of the Arctic contribute more to methane pollution than previously thought, as illustrated in another paper published on 18 July in Nature Communications looking at dry areas of permafrost called ‘upland Yedoma Taliks’ [taliks are permanently frozen soil layers, ed] which are found mostly in northern Siberia, where thawing permafrost is likely to accelerate methane production due to the breakdown of organic material by microbes in the soil.
The study found that the annual methane emissions of the thawing Yedoma talik are almost three times greater, hectare by hectare, than those of the northern wetlands, much greater than currently predicted by climate models. A warning that is as alarming as it is overlooked: the world's permafrost contains three times as much carbon as is currently in the atmosphere, in a region warming three to four times faster than the global average. So much so that this phenomenon may have contributed to the accelerated global warming recorded in recent years that has caused great concern among scientists.
Activists, businesses, scientists and politicians should strengthen their commitment to endorse a binding UN target to reduce CH₄ emissions by at least 45% by 2030 (compared to 2020 levels) even as early as COP29. This is a key issue in order to slow down climate-changing gas concentrations in the atmosphere and contain all the cascading phenomena related to natural methane emissions. The Global Methane Pledge is currently a voluntary, non-binding scheme and excludes a major emitter from the energy sector, Russia. Actions from individual companies are also crucial. If CO₂ has a mammoth level of complexity, methane is much easier to manage. Although, once again, the ball is in the hands of the oil & gas and agribusiness giants.
This article is also available in Italian / Questo articolo è disponibile anche in italiano
Image: Envato