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By Alex Fernández Muerza
This frozen layer of the subsoil is melting natural ecosystems and human infrastructures and could accelerate climate change. Alterations in ecosystems such as the tundra, destabilization of buildings and roads, trees that lose their verticality, affected migratory routes, disturbed marine and river currents or the release of enormous amounts of greenhouse gases into the atmosphere.
Permafrost regions occupy a quarter of the earth's landmass, including the polar and high mountain areas. Greenland is covered almost entirely by permafrost, while Canada, Alaska, northern Europe, Asia or Antarctica have large areas of this frozen subsoil. In this sense, some cities in Northeast Siberia have been built on this natural foundation.
More and more research warns of the progressive melting of this ice sheet as a result of climate change. According to a simulation carried out at the US National Center for Atmospheric Research (NCAR), if current conditions continue, by 2050 half of the frozen subsoil in the northern hemisphere could disappear and, by 2100, up to 90% of the current surface.
By 2050, half of the frozen subsoil of the northern hemisphere could disappear and, by 2100, up to 90% of the current surface
In one of the longest rivers in the world, the Lena, which runs through central Siberia and empties into the Arctic Ocean, the effects are already noticeable. This has been indicated by a study carried out by French, Russian and American scientists, coordinated by the French National Center for Scientific Research (CNRS).
Researchers have found that each year the permafrost melts in this area is greater, which causes that meltwater to end up in the Lena. The increased flow of the river is eroding its banks, posing a serious danger to nearby urban settlements. Also, during the winter, the frozen Lena is used to transport goods by truck. As it is losing its thickness, this "highway" could be in danger, which would affect the economy of the region.
In Spain, Greenpeace recalls that glaciers have suffered a constant retreat since the beginning of the 19th century. Based on the estimates of temperature rise from the Intergovernmental Panel for Climate Change (IPCC), those responsible for this NGO consider that the permafrost environment located in the Pyrenees will also recede, and thus, between 2050 and 2070, the glaciers from this area could melt.
Permafrost and climate change
Scientists studying climate change are placing increasing importance on permafrost. If it continues its thaw, in addition to its negative consequences on ecosystems
or human infrastructures, will contribute to intensify global warming. This is due to the fact that in its upper layers it stores large amounts of CO2 and methane, two of the worst greenhouse gases (GHG). If the permafrost melts, these polluting gases would eventually escape into the atmosphere.
According to various studies, we would be talking about very important GHG quantities. A study by the National Science Foundation in the United States states that the CO2 contained in the permafrost of the northern tundra corresponds to a third of all the carbon that floats in the atmosphere. Thus, he concludes, if the thaw is not stopped, in some years the tundra will add as much or more CO2 to the atmosphere than it removes.
Likewise, scientists from the Russian Academy of Sciences said that the Siberian permafrost, known as "yedoma", could contain about 500 billion tons of CO2, as much as all the rest of the world's permafrost. For its part, a study carried out by a team of American and Russian scientists ensures that this Siberian permafrost is, when melting, releasing five times more methane than previously thought.
On the other hand, permafrost constitutes an authentic record of the planet's temperatures in recent centuries. To do this, scientists drill its interior to extract cylindrical samples with which to study climatic variations. For this reason, edaphologists (soil experts) stress the importance of financing studies on these frozen layers of the subsoil.
Permafrost and the frozen mammoths
The word permafrost comes from the English contraction "perma" (permanent) and "frost" (ice) coined in 1943 by the US Army engineer S. W. Muller. Permafrost, in turn, has two parts: pergelisol, the deepest frozen layer, and mollisol, a more superficial layer that usually thaws, although other experts even distinguish three parts.
The age of permafrost in the northern hemisphere has been estimated thanks to the discoveries of frozen mammoth remains, which became extinct 10,000 or 15,000 years ago, at the end of the last Ice Age. In this sense, scientists from the Russian Academy of Sciences recently discovered in the Siberian permafrost the frozen remains of a six-month-old mammoth that is, according to these experts, the best-preserved specimen found to date.