Tree bark is removing atmospheric methane, study finds

Published in the journal Nature, a team from the University of Birmingham have discovered that microbes in the bark of trees play a significant part in removing atmospheric methane.

While trees have long been used as a tool for mitigating carbon dioxide, with the majority of carbon offsetting projects focussing on tree planting as a means of absorbing CO2 from the atmosphere, this new research suggests that trees have a capacity to absorb a variety of greenhouse gasses roughly 10 per cent higher than previous estimates.

According to the research, microbes within tree bark are removing methane at a scale equal to or greater than that of soil. The bacteria found within soil breaks down methane to use as energy, and it was previously thought that soil was the only terrestrial sink for these methane emissions.

The study involved analysing and investigating a variety of trees across the Brazilian Amazon and Panama in the tropics, temperate broadleaf trees in the UK, and boreal forests in Sweden. The study determined most methane absorption occurred in tropical forests, and the least in cooler boreal forests.

What’s the problem with methane?

Methane is responsible for around 30 per cent of the global warming we’ve seen since pre-industrial times, and is a significant by-product of human-related activity.

The IEA estimates that the production and use of fossil fuels resulted in roughly 120mn tonnes of methane emissions in 2023, with a further 10mn tonnes coming from bioenergy and biomass. What’s more, large methane emissions appear to be on the rise, with satellites detecting 50 per cent more large methane emission event in 2023 compared to 2022. A total 5mn tonnes of methane were detected from major fossil fuel leaks around the world.

Overall, the energy sector accounts for over a third of total methane emissions attributed to human activity, so reducing emissions from fossil fuels stands to reduce global methane emissions significantly. The IEA estimates that roughly 80mn tonnes of annual methane emissions can be avoided through the use of existing technologies.

However, agriculture remains the principal source of methane emissions. In 2023, agriculture contributed 142mn tonnes of methane to the atmosphere, so a system that focusses on sustainable agricultural practices and fossil fuel abatement is best positioned to tackle methane emissions.

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