An international group of scientists led by specialists from the Center. Helmholtz's study of the ocean found that the onset of ice ages provoked an increase in volcanic activity. According to the results obtained, the concentration of carbon dioxide in the atmosphere during a cold snap can remain stable.
The relationship between the global average temperature and the content of greenhouse gases in the Earth's air envelope has long been established. As shown by paleoclimatic data, the end of the last ice age about 11 thousand years ago led to the eruption of volcanoes that were on land. This, according to scientists, could be due to a decrease in pressure on the earth's mantle due to the melting of glaciers. As a result, a huge amount of carbon got into the atmosphere, which in turn accelerated the process of global warming. Such positive feedback should also provoke the opposite effect - lead to a fall due to a cooling of carbon dioxide.
At the same time, 70-85 thousand years ago, when the global average temperature decreased due to a change in the position of the Earth's axis, the carbon dioxide content in the planet's atmosphere remained unchanged. After modeling geological processes in the earth's interior, the researchers suggested that the decline in sea level and the increase in glacial mass reduced the pressure that was exerted on the upper layers of the earth's mantle under the oceans. This, in turn, led to the melting of rocks and the release of magma.
Despite the fact that during this period of time, eruptions of terrestrial volcanoes occurred infrequently, hot spots appeared in the region of the mid-ocean ridges - places under the lithospheric plates, in which the temperature of the mantle is much higher than the temperature of the surrounding rocks, as a result of which there is a high volcanic activity. Due to these geological processes, a negative feedback was provided between carbon dioxide and glaciation, stopping the decline in carbon dioxide concentration for about 15 thousand years. However, about 70 thousand years ago, the process of reducing carbon dioxide in the atmosphere abruptly resumed.