NATURAL MECHANISMS OF PALEOCLIMATIC CHANGES IN THE NORTHERN BLACK SEA REGION AND ITS SOCIAL CONSEQUENCES

The path of social development of mankind, starting from the Neolithic era, is to a certain extent modulated by climatic changes. Analysis of the alternation of warm and cold (dry and wet) periods in different territories allows one to assess the causes of many historical events. Climate change is a trigger, an additional hazard factor in a situation of political and socio-economic tension. Consider the impact of sharp climate fluctuations in the Northern Black Sea region on the development and decline of the city of Tire, which was founded by the Milesian Greeks at the mouth of the deep Dniester River in the 6th century BC. The period between 200 BC and 250 AD known as the "Roman climatic optimum". The warm, humid and predictable climate was uniquely favourable for the region's major crops. By the third century, the climate became drier and cooler, with frequent droughts and crop failures. Climate change has reduced the empire's resilience to various shocks, including pandemics. An outbreak of smallpox happened at the end of the 2nd century, the 3rd century was marked by an epidemic (Ebola virus), the middle of the 6th century - "Justinian's plague". In the ten years before the outbreak of the plague, Europe had the lowest atmospheric temperature in several centuries. Further, in connection with climate changes (severe drought in Europe in the 4th century), the migration of the Huns begins, who are called "climate refugees on horseback".

Climatic changes in the Northern Black Sea region are quite fully determined by long-period trends in circulation processes in the North Atlantic, which are responsible for the formation of dry or humid climatic epochs. It is possible to predict trends in hydrometeorological parameters with a lead time from a season to several decades based on the forecast trends of the North Atlantic Oscillation (NAO) and Atlantic Multidecadal Oscillation index.

Using the example of changes in the runoff of the Dniester River, it is shown that extreme years in terms of water content in the spring period (correlation of about -0.7) take place with stable negative winter NAO indices. Such a structure of pressure fields over the North Atlantic indicates a weakening of the zonal circulation and a displacement of the trajectories of cyclones to the south, which leads to abundant precipitation in the Dniester catchment area.