Study suggests: Arctic warming depends on large earthquakes

A 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 sharply and suddenly, especially in the Arctic.

In the Arctic, one of the factors driving climate warming is the release of methane from permafrost. Since researchers began monitoring temperatures in the Arctic, the region has seen two periods of rapid warming: first in the 20s and 30s, and then from 1980 until today.

The research

The research was conducted at MIPT with the support of the Russian Science Foundation, grant no. 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 geophysical research of the Arctic and continental margins of the World Ocean. In his paper, the scientist hypothesizes that the sharp, unexplained 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.

The answer to the first question came from the analysis of historical data. The Aleutian Arc has been found to actually be the site of two series of large earthquakes in the 20th century*. Each preceded a sharp rise in temperature of about 15-20 years.

To answer the second question a dynamics model was needed that describes the propagation of so-called tectonic waves. The model predicts they should travel about 100 kilometers per year. This fits with the delay between each of the large series of earthquakes and the subsequent temperature rise, as the disturbances took 15 to 20 years to be transmitted over 2.000 kilometers.

In answer to the third question, the researcher proposed the following explanation: Strain waves arriving in the shelf zone cause minor additional stresses in the lithosphere, which are sufficient to disrupt the internal structure of metastable gas hydrates and permafrost that stores the captured methane. This releases methane into the shelf water and the atmosphere, leading to climate warming in the region due to the greenhouse effect.

Arctic: not just man-made

There is a clear correlation between large earthquakes in the Aleutian arc and the phases of climate warming. There is a mechanism to physically transmit 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 explanation. Importantly, it explains a known fact, the sharp increase 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 discussion and will likely be improved, and there is much to be done to confirm or rule out the proposed mechanism.

* The first series of earthquakes began with a magnitude 8 earthquake in 1899 in the eastern part of the Aleutian Arc, followed by two more large earthquakes in the western part of the islands, with magnitudes 8,3 and 8,4. The second series began with an 8,6 magnitude earthquake in 1957, followed by the 9,3 magnitude 1964 earthquake in Alaska. The following year, an 8,7 magnitude earthquake shook the western part of the arc. Each of these devastating seismic events had underground sources that extended for hundreds of kilometers.