An MIPT researcher proposes a new explanation for the rapid warming of the Arctic. In his recent article on Geosciences , suggests that warming may have been triggered by a series of large earthquakes.
Global warming is one of the REALLY pressing issues. It is widely believed that it is caused by human activity, which increases the concentration of greenhouse gases in the atmosphere. However, this view does not explain why temperatures sometimes rise abruptly and suddenly, especially in the Arctic.
In the Arctic, one of the factors determining global warming is the release of methane from permafrost. Since researchers began monitoring temperatures in the Arctic, the region has witnessed two periods of rapid warming: first in the 20s and 30s, and then from 1980 to the present.
The research was conducted at MIPT with the support of the Russian Science Foundation, grant n. 20-17-00140.
Leopold Lobkovsky, author of the study reported in this article, is a member of the Russian Academy of Sciences and head of the MIPT Laboratory for the geophysical research of the Arctic and continental margins of the World Ocean. In his article, the scientist speculates that the abrupt inexplicable temperature changes may have been triggered by geodynamic factors. In particular, he pointed to a series of large earthquakes in the Aleutian Arc, which is the seismically active area closest to the Arctic.
To test his hypothesis, Lobkovsky asked himself three questions.
- First, did the dates of the great earthquakes coincide with the temperature jumps?
- Secondly, what is the mechanism that allows earthquakes to spread over 2.000 kilometers from the Aleutian Islands to the Arctic Shelf region?
- Third, how do these disturbances intensify methane emissions?
The answer to the first question came from the analysis of historical data. It turned out that the Aleutian Arch is actually the site of two series of major earthquakes in the 20th century*. Each preceded a sharp rise in temperature of about 15-20 years.
To answer the second question it took a model of dynamics that describes the propagation of so-called tectonic waves. The model predicts that they should travel about 100 kilometers per year. This agrees with the delay between each of the major series of earthquakes and the subsequent rise in temperature, as the perturbations took 15 to 20 years to be transmitted over 2.000 kilometers.
In answer to the third question, The researcher proposed the following explanation: The deformation waves arriving in the platform zone cause less additional stresses in the lithosphere, which are sufficient to disrupt the internal structure of the metastable gas hydrates and the permafrost that stores the captured methane. This releases methane into the platform water and the atmosphere, leading to climate warming in the region due to the greenhouse effect.
Arctic: not just the work of man
There is a clear correlation between large earthquakes throughout the Aleutians and the phases of climate warming. There is a mechanism to physically transmit the stresses in the lithosphere at the appropriate speeds. And these additional stresses are capable of destroying metastable gas hydrates and permafrost, releasing methane. Each of the three components in this scheme is logical and lends itself to mathematical and physical explanations. Importantly, it explains a known fact, the sharp rise in temperature anomalies in the Arctic, which had remained unexplained by the previous model.
Leopold Lobkovsky
According to the researcher, his model will benefit from the discussion and is likely to be improved, and there is much that needs to be done to confirm or rule out the proposed mechanism.
