The study points to the region's unique geology and climate warming as causes for the release of methane gas trapped within the permafrost. "There are very, very specific conditions that allow for this phenomenon to happen," said Ana Morgado, a chemical engineer at the University of Cambridge and one of the study's authors. "We're talking about a very niche geological space."
The research, published in 'Geophysical Research Letters', explores how these methane releases are driven by warming temperatures and underground pressure changes, rather than just permafrost melting alone.
Exploding Permafrost Mystery
The Yamal Peninsula, a low-lying area in north-central Russia, gained attention in 2014 when a massive crater appeared, measuring 70 meters (230 feet) across. Over the next decade, additional craters were found both on the Yamal Peninsula and the nearby Gydan Peninsula. Initial explanations ranged from permafrost melting to methane gas buildup due to proximity to natural gas reserves. However, this study suggests that warming alone is not sufficient to trigger such explosions.
Surface warming is now believed to drive rapid underground pressure shifts, leading to methane gas releases. "We knew that something was causing the methane hydrate layer to decompose," said Morgado. "It's a bit like detective work."
Osmosis and the Explosions
The research team investigated whether physical or chemical processes triggered the explosions. According to Julyan Cartwright, a geophysicist at the Spanish National Research Council and study co-author, physical factors are likely responsible. He explained, "Either a chemical reaction happens, and you have an explosion, like dynamite blowing up, or you pump up your bicycle tire until it blows up - that's physics."
The study concluded that physical forces were the cause, specifically osmosis, where water movement creates pressure changes. Warming alters the thick clayey permafrost of the Yamal Peninsula, allowing water from thawing layers above to force its way into salty, unfrozen underground water pockets known as cryopegs. This pressure buildup eventually causes methane hydrates to destabilize and explode.
The combination of pressure, warming, and unique underground layers all contribute to this explosive process, which can take decades to unfold, linking its origins to climate warming beginning in the 1980s.
Global Implications
Though rare, these methane explosions could have a significant impact on global warming due to the release of methane, a potent greenhouse gas. "This might be a very infrequently occurring phenomenon," Morgado explained, "but the amount of methane that's being released could have quite a big impact on global warming."
Research Report:Osmosis drives explosions and methane release in Siberian permafrost
Related Links
University of Cambridge
Beyond the Ice Age
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