Methane is an incredibly potent greenhouse gas. Although it breaks down far quicker in the atmosphere than carbon dioxide, it traps heat around 36 times more effectively in the long-term. If lots of it is released in short bursts, it acts as a powerful global warming catalyst, so ideally we’d want to keep as much of it from entering the atmosphere as possible.
Unfortunately, there are two major sources of methane in the natural world that climate change is threatening to release: microbial methane and geological methane. Worryingly, a new study suggests that the caches of the latter are more unstable and prolific than previously thought.
Microbial methane gets a lot of media attention, and rightly so. It’s found beneath terrestrial permafrost (frozen snow) when the organic matter there decomposes in a low-oxygen environment, and it can also be found beneath the seafloor, trapped in icy compounds. An increasingly warmer atmosphere and a rapidly warming hydrosphere means that these icy prisons become unstable; decomposition kicks up a gear, the ice thaws, and both begin to unleash their greenhouse gas reserves.
This new study in Scientific Reports takes a look at the far more ancient geological methane, formed at the same time as the oil deposits they overlie.
Between 2012 and 2013, a team led by the GFZ German Research Centre for Geosciences took aerial geochemical samples from above the permafrost-coated Mackenzie Delta in Canada. They found that, contrary to typical microbial methane emissions rates, there was around 13 times more methane in the air than one would expect.
This suggests that geological methane is seeping out into the atmosphere at a rate far faster than anyone previously expected.
Additionally, despite the fact that these geological methane hotspots only cover about 1 percent of the total area of the basin, they contribute to around 17 percent of the annual methane emissions of the region. This means that this source of methane is disproportionately contributing towards the Earth’s greenhouse effect.
Ultimately, if the results of this study are replicated in permafrost zones elsewhere around the globe, this suggests that we’re heading towards a dangerous future.
As the mercury continues to rise due to human activity, increasing amounts of both microbial and biological methane will be unleashed in what will amount to a self-reinforcing cycle. Although there’s some debate as to when the tipping point will be, there’s a chance that beyond a certain degree of warming, this methane release will become unstoppable.
The researchers at GFZ point out that geologic methane is rarely included in climate change models. This study, then, suggests that the most cutting-edge predictions as to how scorched the future Earth will be are, yet again, too conservative.
This may sound like bad news, but instead of losing hope, this research should spur us on to fix the climate crisis before we go past a hypothetical point of no return.
