Earthquakes could cause sharp climate warming in the Arctic
The press service of the Ministry of Science and Higher Education spoke about a new assumption regarding what could cause a sharp warming of the climate in the Arctic in 1979-1980, as well as the intensive destruction of glaciers in Antarctica at the end of the last century.
Geophysicists from the P.P. Shirshov Institute of Oceanology of the Russian Academy of Sciences, the Laboratory for Joint Research of the Arctic Shelf System of Tomsk State University, the Laboratory for Geophysical Research of the Arctic and the Continental Margins of the World Ocean of the Moscow Institute of Physics and Technology, the Institute for the Theory of Earthquake Prediction and Mathematical Geophysics of the Russian Academy of Sciences, the Institute Geothermal Research and Renewable Energy Sources of the Russian Academy of Sciences (Makhachkala) and the Institute of Geosphere Dynamics of the Russian Academy of Sciences under the leadership of Academician of the Russian Academy of Sciences Leopold Lobkovsky took pert in the studies.
According to scientists, it was catastrophic earthquakes that gave a sharp start to warming in the Arctic in 1979-1980. From an anthropogenic point of view, this increase in temperature is difficult to explain, since there was no significant increase in industrial production during that period of time.
Experts have checked whether there is a spatio-temporal correlation between the onset of warming in the Arctic and the strongest earthquakes in the Aleutian subduction zone closest to the Arctic shelf. It turned out that such a correlation exists, but with a time shift of about 20 years.
According to historical data, the most powerful earthquakes in the Aleutian arc occurred in the middle of the last century in a fairly narrow time interval of 1957–1965.
"The question arises, what is the nature of the twenty-year delay in climate change? The answer to it is given by the theory of deformation tectonic waves that arise in the elastic lithosphere - the solid shell of the Earth. These waves are generated by the strongest earthquakes and propagate in a horizontal direction at a speed of about 100 km / year. At such a speed the deformation wave will cover a distance of about 2,000 km between the Aleutian arc and the Arctic shelf in just 20 years," the report says.
Climate warming can be associated with the destruction of metastable gas hydrates in the frozen rocks of the Arctic shelf, and with additional stresses from deformation waves. Metastable gas hydrates contain free methane inside, locked in thin layers of ice. The destruction of these ice layers leads to the release of methane from frozen rocks, its release into the water column of the shallow shelf and further into the atmosphere. The strong greenhouse effect of methane leads to noticeable warming.
According to scientists, a similar mechanism works for the Antarctic. Here, the onset of the phase of anomalous climate warming occurred almost simultaneously with the Arctic. In 1960, the most powerful earthquake with a magnitude of 9.5 occurred in the central part of the Chilean zone, which is relatively close to Antarctica. A particularly noticeable increase in temperature in Antarctica has been recorded in recent decades against the background of a sharp intensification of the destruction of ice shelves, primarily in the area of the Antarctic Peninsula.
"The proposed seismogenic-trigger mechanism makes it possible to explain why the polar regions are heating up much faster than the main part of our planet. The new geodynamic model of Russian scientists also predicts further acceleration of glacier destruction and climate warming in Antarctica in the near future due to an unprecedented increase in the frequency of strong earthquakes in South Pacific in the late 20th and early 21st centuries," the press service said.
A new University of Alaska report aims to help state leaders craft energy policies as the Arctic changes
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