'According to paleoclimatologists, the main cause of the majority of climatic extremes of that period was volcanic activity. Often these changes occurred on a global scale,' explains Rustam Ganiev. 'The main consequences of natural disasters - in our case in the territory of the Türkic Kaganate - were the cooling and prolonged droughts of 536, 581 and 679, as well as an early and protracted winter with heavy snowfalls. The most critical situation was noted among the Turks in 627-630, when the Khaganate practically ceased to exist because of the mass death of livestock and hunger.'
The authors of the article singled out several periods during which the most important events that changed the course of Turkic history took place:
534-550 - The first mention of the Türkic Khaganate and its "Golden Age";
581-583 - Separation of Khaganate into the Western and Eastern Khaganates;
627-630 - The conquest of the eastern Turks by China;
679-687 - The Second "Golden Age" of the Eastern Turks.
In the first period 536, 537, 541, 543 and 545 years were anomalously cold. The consequences were severe for many people of Middle Ages: one of the most serious epidemics occurred - the Justinian Plague - the first historically known pandemic, with millions of victims.
'It was believed that the plague started in Egypt in 540-541, reached Constantinople through the Mediterranean channels and spread through Byzantium, North Africa, Europe, Central Asia, and Arabia,' explains Rustam Ganiev. 'However, according to recent studies, the causative agent of plague appeared in Central Asia, where the Turks lived. As the Silk Road ran through this territory, traders could spread the pandemic: Byzantium was the main trading partner of the Khaganate and China; about 80% of the population in the northern part of which died at that time. It was at the end of this period that the Turks began to strengthen their position: they subjugated their neighbors, concluded trade and military-political agreements with China, and by 551 became independent, and their ruler receive the title "khagan".
During the study, the authors of the article used data from tree-ring chronologies (show climatic differences), samples of ice cores of Greenland and Antarctica (volcanic eruptions). The third set of data formed the Chinese dynastic chronicles, which reflect the main historical information about the ancient Turks.
'The Ural Division of the Russian Academy of Science has the largest in Europe, and perhaps in the world, amount of fossil wood. For nearly 40 years, the Institute's employees have been collecting semi-fossil wood on the Yamal Peninsula. To build the "Yamal chronology," they have studied more than 3,500 samples,' explains Vladimir Kukarsky. 'In the study, we rely on ice core data, the Yamal, Altai, Mongolian tree-ring chronologies, which can be found in the public domain. There was a large number of materials, and we had to choose the ones suitable for our research: to select chronologies that react to changes in temperature, humidity of the territory, extreme events. For example, a volcanic eruption in the tropics can be traced in tree rings in both Altai and Yamal: a huge amount of ash creates the effect of a "volcanic winter," and thin rings form in the trees, and sometimes the cellular structure is broken.'
According to the researchers, dendrochronology is one of the most accurate ways to date extreme events in nature. 'We plan to apply for a grant to extend the chronology of research to the millennium. A more global goal is to create a historical and climatic chronology for the nomadic societies of Central Asia in the first millennium of our era. This is a very complex, large, labor-intensive and expensive project,' says Rustam Ganiev.
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The results of the study are published in the journal Climatic Change (Impact Factor - 3.57, Springer Nature publishing company): https://link.springer.com/article/10.1007/s10584-018-2236-9
Journal
Climatic Change