A study published in Nature Communications has estimated that historical methane-climate feedback is four times higher than assumed in the Sixth Assessment Report of the Intergovernmental Panel on Climate Change, which in more layman’s terms means that global heating is four times more influential in accelerating methane concentrations in the atmosphere than previously thought.
Methane in the atmosphere has been rising rapidly since 2007, and particularly in the two years of the pandemic, something of a puzzle when industrial activity slowed. Investigating this, the researchers authoring the study, Chin-Hsien Cheng and Simon Redfern, have hypothesised that hydroxyl radicals in the atmosphere which usually break down methane are being consumed instead by higher levels of carbon monoxide, caused by wildfires. If this is true, it would be grim news for hopes to mitigate climate change, given methane’s potent greenhouse warming effect and the likelihood of more frequent wildfires.
It is possible instead that the higher levels of methane observed in the atmosphere are from agriculture, landfill or industrial activity, or the release of methane from warming wetlands or Arctic tundra, or a combination of all of these. Yet the hydroxyl radical hypothesis is a strong mechanistic one, particularly as it fits with accelerated atmospheric methane levels over the pandemic period. Simon Redfern said of the finding that it “was a really shocking result, and highlights that the effects of climate change can be even more extreme and dangerous than we thought”.
If the findings are indeed true, then more of a focus on reducing methane emissions, already known to be something of a ‘low hanging fruit’ for greenhouse gas emissions abatement, will be needed – urgently.