Traverse deep into northern Siberia, and you’ll find the Yenisey-Khatanga Basin. As of late, this remote part of the world is predominantly known for two things: its untapped potential as a massive source of oil and gas, and its proximity to the wildfires that have raged in Siberia this summer.
Now, scientists suggest another factor that demands our attention: According to a study published Monday in the journal Proceedings of the National Academy of Sciences, considerable amounts of methane are being released from a previously unexplored source.
Arctic methane is typically connected to two sources: organic matter in permafrost and methyl clathrate (molecules of methane frozen in ice crystals). This study spotlights a third — one released from fractures and pockets in the permafrost zone that’s become unstable due to warming.
As the climate crisis worsens, understanding this study’s findings “may make the difference between catastrophe and apocalypse,” lead author Nikolaus Froitzheim, a professor at the University of Bonn’s Institute of Geosciences in Germany, tells Inverse.
What you need to know first — The thawing of the Siberian permafrost — a mixture of rock, ice, soil, and the organic remains of animals and plants — is associated with the release of methane in the atmosphere. Global warming has led to an increased thawing of the permafrost.
Methane is a potent greenhouse gas emission with 84 to 86 times the warming power of carbon dioxide over a 20-year period.
After conducting a satellite analysis of the Yenisey-Khatanga Basin, Froitzheim and colleagues found we’ve been overlooking another crucial source of methane emissions from the Siberian permafrost: sites of “thermogenic methane.”
How the discovery was made— The researchers used an interactive satellite mapping technology, known as PULSE, to calculate methane emissions in the air above the Yenisey-Khatanga Basin in Siberia.
“There is a lot of natural gas in the subsurface of Siberia.”
The researchers looked specifically at methane emissions following a heat wave in Siberia in June 2020, as well as methane emissions in the area in spring 2021. They also compared the methane emissions on the satellite map to a geological map showing where certain rock formations occur.
The researchers then made an alarming discovery:
“We found that two elongated areas of elevated methane concentration on the PULSE map perfectly coincide with two stripes where limestone formations occur in the subsurface,” Froitzheim says.
What’s new — Those limestone formations are likely sites of “thermogenic methane” or natural gas deposits of methane hidden deep underneath the permafrost. Natural gas, the team writes, can be “trapped under or within the permafrost layer and released when it thaws.”
The methane couldn’t have come from the usual microbes breaking down organic matter in the soil, since there is very little soil in these limestone formations.
Heat “made this mixture unstable and opened pathways.”
Instead, Frotzheim suspects record-breaking temperatures disturbed fractures in the limestone, providing an opportunity for natural gas from deeper within the permafrost to escape into the atmosphere.
“Our hypothesis is that the heat made this mixture unstable and opened pathways through which natural gas from depth could reach the surface,” Frotzheim says. “There is a lot of natural gas in the subsurface of Siberia, and some of these reservoirs may have been tapped.”
Comparing maps over a one-year period between May 2020 and May 2021, the scientists found that “atmospheric methane concentrations have increased considerably during and after the 2020 heat wave.”
“After” is key: The increase in methane was highest in June/August 2020 as well as in March/April 2021, demonstrating how warming can trigger methane release long after the initial heat wave.
Why it matters — The events in Northern Siberia are all, in a way, connected: the fires, the hunt for natural fuel, and the release of a powerful greenhouse gas.
Methane traps heat in the atmosphere and plays a major role in climate change. The heat wave that ignited Siberia’s wildfires is part of a trend driven by human-induced climate change — so is the thawing of Siberia’s permafrost. The extraction of oil and gas also releases methane. These factors are all connected.
It’s a domino effect that doesn’t appear to be slowing down: Record-breaking temperatures hit Siberia in 2020 and once again in the summer of 2021.
As temperatures continue to skyrocket due to the climate crisis, the permafrost thaw may unleash unknown quantities of this deep methane gas into the atmosphere. In 2018, NASA predicted a possible “future boost” of methane from Arctic permafrost — that prediction is coming true.
Based on their findings, the researchers conclude: “As a result, the permafrost–methane feedback may be much more dangerous than suggested by studies accounting for microbial methane alone.”
What’s next — Methane may be coming from deep within the Siberian ice, but scientists are still scratching the surface of permafrost research.
Froitzheim and his colleagues still aren’t sure why methane emissions began spiking more than half a year after the summer 2020 heat wave.
The team calls on more scientists to conduct research to “find out how fast and how much methane may be emitted this way,” including an analysis of methane in air samples and calculations of methane gas destabilization in the rocks.
While these measures are a way for scientists to better understand the exact amount of methane released due to permafrost, they’re not a solution.
These findings don’t necessarily mean the permafrost is beyond repair, the scientists suggest. The amount of methane being released from these deep methane reserves are relatively small compared to, say oilfields in Libya or wetlands in India, Froitzheim says. To have any chance of halting the release of methane from the permafrost we need to immediately begin reducing greenhouse gas emissions from fossil fuels and other industries.
“I do not think that these particular observations mean that we have passed a point of no return,” Frotzheim says.
Abstract: Anthropogenic global warming may be accelerated by a positive feedback from the mobilization of methane from thawing Arctic permafrost. There are large uncertainties about the size of carbon stocks and the magnitude of possible methane emissions. Methane cannot only be produced from the microbial decay of organic matter within the thawing permafrost soils (microbial methane) but can also come from natural gas (thermogenic methane) trapped under or within the permafrost layer and released when it thaws. In the Taymyr Peninsula and surroundings in North Siberia, the area of the worldwide largest positive surface temperature anomaly for 2020, atmospheric methane concentrations have increased considerably during and after the 2020 heat wave. Two elongated areas of increased atmospheric methane concentration that appeared during summer coincide with two stripes of Paleozoic carbonates exposed at the southern and northern borders of the Yenisey-Khatanga Basin, a hydrocarbon-bearing sedimentary basin between the Siberian Craton to the south and the Taymyr Fold Belt to the north. Over the carbonates, soils are thin to nonexistent and wetlands are scarce. The maxima are thus unlikely to be caused by microbial methane from soils or wetlands. We suggest that gas hydrates in fractures and pockets of the carbonate rocks in the permafrost zone became unstable due to warming from the surface. This process may add unknown quantities of methane to the atmosphere in the near future.