2024-07-29 23:34:25
Permafrost is an area of permafrost that swells as liquids accumulate below the surface. According to the Siberian Branch of the Russian Academy of Sciences (SBRAS) conducted research, these bumps can be caused by two different “systems”: open and closed. In an open system, water and gas accumulated under the permafrost move and erupt through cracks to the surface. But in a closed system, water and gas are trapped in a pocket that swells and increases the pressure on the permafrost.
The open system is similar to an idea put forward by scientists earlier this year. January 12 in the EarthArXiv database in a published preliminary review, the researchers said that natural gas moving between the rocks and the permafrost above them is driving the melting from below. This melting creates pockets in the permafrost where liquids can collect, but they are not completely protected from the gases below or at the surface. The pockets grow larger as more and more gas enters them, causing further melting and increasing pressure, causing the earth to swell.
The gas is mainly thermogenic methane, which is likely to form continuously as a byproduct when organic matter is heated. “We call it the kitchen [ten apačioje]because it’s like cooking, which creates gas,” says Helge Hellevang, professor of environmental geosciences at the University of Oslo in Norway and lead author of the review.
In a closed system, gas and water come from deep within the rocks. According to the SBRAS researchers, the fluids rise and form a pocket inside the permafrost that is “surrounded on all sides by frozen rock,” preventing it from erupting outwards.
Despite the fact that open and closed systems are different, nothing prevents one of them from turning into the other, as the permafrost evolves, H. Hellevang says. An open system may even have to become closed to form a crater, he said.
Scientists still don’t know exactly how gas accumulates to form permafrost – but they do know that permafrost can rupture on its own, opening huge holes in the permafrost. One such example is the Yamal crater, which is about 20 m wide and 50 m deep. Helicopter pilot 2014 spotted a crater 42 km from the Bovanenkovo gas field in Russia’s northern Yamal Peninsula. Since then, scientists have recorded seven more such giant craters in Yamal and the neighboring Gydan Peninsula.
SBRAS researchers claim that frozen mountains “explode” and form craters, but Hellevang disagrees. Explosions require an ignition source — such as extreme heat or electricity — but “it’s very difficult to ignite gas at subzero temperatures,” he says. “It’s more like an eruption than an explosion,” explains the scientist.
It is possible that open systems can create the pressure necessary for an eruption, but this would require a very small flow of gas from the system, says H. Hellevang. Closed systems are more likely to cause eruptions because they build up more pressure immediately, he says.
Both systems may experience an increased risk of eruption as temperatures rise and permafrost melts. “Climate change weakens the surface due to warming from above,” says the scientist. At some point, the permafrost will become so thin that it cannot withstand the pressure of the gas pockets below, which could lead to eruptions.
Sudden gas eruptions pose a danger to people living on the Yamal and Gydan peninsulas and to infrastructure such as gas pipelines. Another big concern, Hellevang says, is that “if the permafrost is a cover for all this massive methane…then these craters could also become pathways for even more methane leaks in the future.” And this can lead to even greater warming, Live Science writes.
2024-07-29 23:34:25