Now scientists are suggesting another factor that requires our attention: according to a study published Monday in the journal Proceedings of the National Academy of Sciences, considerable amounts of methane are released from a previously unexplored source.
Arctic methane is generally linked to two sources: organic matter in permafrost and methyl clathrate (methane molecules frozen in ice crystals). This study sheds light on a third – one freed from fractures and pockets in the permafrost area that has become unstable due to warming.
As the climate crisis worsens, understanding the results of this study “may mean the difference between disaster and apocalypse,” said lead author Nikolaus Froitzheim, professor at the Institute of Geosciences at the University of Bonn in Germany. Inverse.
What you need to know first – The thawing of Siberian permafrost – a mixture of rock, ice, soil, and organic remains of animals and plants – is associated with the release of methane into the atmosphere. Global warming has resulted in increased permafrost melting.
Methane is a powerful greenhouse gas with 84 to 86 times the warming power of carbon dioxide over a 20-year period.
After performing a satellite analysis of the Yenisey-Khatanga basin, Froitzheim and his colleagues discovered that we had overlooked another crucial source of methane emissions from Siberian permafrost: “thermogenic methane” sites.
How the discovery was made— The researchers used interactive satellite mapping technology, known as PULSE, to calculate methane emissions to the air over the Yenisey-Khatanga basin in Siberia.
” There is a lot of natural gas in the basement of Siberia.
The researchers specifically looked at methane emissions following a heat wave in Siberia in June 2020, as well as methane emissions in the region in the spring of 2021. They also compared methane emissions on the satellite map to a geological map showing where some rock formations are located.
The researchers then made an alarming discovery:
“We found that two elongated areas of high methane concentration on the PULSE map coincide perfectly with two bands where there are limestone formations in the subsoil,” explains Froitzheim.
What’s up – These limestone formations are likely sites of “thermogenic methane” or natural gas methane deposits hidden deep under the permafrost. Natural gas, the team writes, can be “trapped under or in the permafrost layer and released when it thaws.”
The methane could not come from the usual microbes degrading the organic matter of the soil, because there is very little soil in these limestone formations.
The heat “made this mixture instable and paved the way.
Instead, Frotzheim suspects record-breaking temperatures disrupted fractures in the limestone, providing an opportunity for natural gas from deep in the permafrost to escape into the atmosphere.
“Our hypothesis is that the heat made this mixture unstable and opened up pathways through which natural gas from the depths could reach the surface,” says Frotzheim. “There is a lot of natural gas underground in Siberia, and some of these reservoirs may have been tapped. “
By comparing maps over a one-year period between May 2020 and May 2021, scientists found that “atmospheric concentrations of methane increased dramatically during and after the 2020 heat wave”.
“After” is key: The increase in methane was highest in June / August 2020 as well as March / April 2021, demonstrating how warming can trigger the release of methane long after the initial heat wave.
Why is this important – The events in North Siberia are all, in some way, linked: 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 sparked the forest fires in Siberia is part of a trend driven by human-induced climate change, as is the thawing of Siberian permafrost. Oil and gas extraction also releases methane. These factors are all linked.
It’s a domino effect that doesn’t seem to be slowing down: record temperatures hit Siberia in 2020 and again in the summer of 2021.
As temperatures continue to soar due to the climate crisis, thawing permafrost can release unknown amounts of this methane gas deep into the atmosphere. In 2018, NASA predicted a possible “future increase” in methane from arctic permafrost – that prediction is coming true.
Based on their findings, the researchers conclude: “As a result, the permafrost-methane feedback can be much more dangerous than studies that consider microbial methane alone suggest. “
And after – The methane may have come from deep in the Siberian ice, but scientists continue to scratch the surface of permafrost research.
Froitzheim and his colleagues still don’t know why methane emissions started to rise more than six months after the summer 2020 heatwave.
The team calls for more scientists to conduct research to “find out how quickly and how much methane can be emitted this way,” including analysis of methane in air samples and calculations of methane destabilization in air. rocks.
While these measurements are a way for scientists to better understand the exact amount of methane released as a result of permafrost, they are not a solution.
These results do not necessarily mean that the permafrost is irreparable, scientists suggest. The amount of methane released from these deep methane reserves is relatively small compared to, say, oil fields in Libya or wetlands in India, Froitzheim says. To have any chance of stopping the release of methane from permafrost, we must immediately start reducing greenhouse gas emissions from fossil fuels and other industries.
“I don’t think these particular observations mean we’ve passed a point of no return,” Frotzheim said.
Abstract: Anthropogenic global warming could be accelerated by a positive feedback from the mobilization of methane from melting arctic permafrost. There are great uncertainties about the size of carbon stocks and the magnitude of possible methane emissions. Methane cannot only be produced from the microbial decomposition of organic matter in thawing permafrost soils (microbial methane), but can also come from natural gas (thermogenic methane) trapped under or in the permafrost layer and released during thaw. In the Taymyr Peninsula and its environs in North Siberia, the area of the world’s largest positive surface temperature anomaly for 2020, atmospheric methane concentrations increased dramatically during and after the 2020 heat wave. Two elongated zones of increased concentration of methane in the atmosphere that appeared during the summer coincide with two bands of Paleozoic carbonates exposed at the southern and northern borders of the Yenisey-Khatanga basin, a sedimentary basin containing hydrocarbons between the Siberian craton. to the south and the Taymyr Belt Fold to the north. Above carbonates, soils are thin to nonexistent and wetlands are scarce. The maxima are therefore unlikely to be caused by microbial methane from soils or wetlands. We suggest that the gas hydrates in the fractures and pockets of carbonate rocks in the permafrost zone have become unstable due to the warming of the surface. This process may add unknown amounts of methane to the atmosphere in the near future.