or What threatens us with lowering the sea level
Unique in the diversity of flora and fauna, the Caspian Sea is the largest closed body of water in the world – by the nature of the formation processes, the history of origin and its size, it is considered to be the sea. Nowadays, the Caspian Sea is experiencing another lowering of the water level.
If some people are seriously concerned about this, others do not see this as a special reason for concern.
Mirzakhan Mansimov, the head of Iqlim (“Climate”), a company engaged in environmental research, Doctor of Philosophy in geographical sciences, in an interview with the correspondent of the Baku Worker newspaper, noted that concern among the public and those whose activities are related to the study of the sea appears both when the level of the Caspian Sea rises strongly and when it drops significantly.
– It is known that the level of the Caspian Sea is subject to cyclicity, so is there a reason for alarm?
– Yes, the level of the Caspian Sea varies according to a certain periodicity, but these cycles are quite large and can reach 200-300 years. This is a natural process, but it creates a number of problems. In general, the Caspian Sea has repeatedly experienced a strong rise and fall in the water level. So, in 1930-1977 it dropped by 2.8 m, in the period 1978-1996 it rose sharply by 2.2 m, and since 2007 there has been a decrease in sea level by 2.3 m. To date, the level of the largest lake in the world is at the minimum that was observed in 1977, and this is 29 m below the level of the World Ocean.
– What are the negative consequences of the shallowing of the sea?
– First of all, this has a negative impact on maritime navigation, canals, ports and farms whose economic development is connected with the Caspian Sea. The Northern Caspian Sea – the Kazakh and Russian coasts – is particularly affected by shallowing and sea level rise. This is due to the fact that there the rise or fall of the water level by 30-50 cm leads to a change in the landscape of the coast at a distance of tens of kilometers. In the period 2007-2022, due to the lowering of the water level, the sea area decreased by about 30 thousand km2 (90% of the coastal zone of the Northern Caspian). Of course, this also creates certain difficulties for the ports of Azerbaijan.
– Is there a chance that the level of the Caspian Sea will start to rise again?
– Based on the physical and geographical location of the water area and the catchment area of the Caspian Sea, and most importantly from its isolation, it can be concluded that fluctuations in the level of the Caspian Sea are its normal state, therefore there is nothing unusual in its increase and decrease. Despite the fact that this reservoir has been well studied, it is difficult to make accurate forecasts now, especially long-term ones. Evaluation of the results of paleoclimatic studies of previous years and instrumental observations conducted for
200 years, shows that fluctuations in the level of the Caspian Sea in the range from -30 to -25 m have occurred over the past 12 thousand years. It is this scale of level fluctuations (the “risk zone”) that should be taken into account when developing economic measures in the coastal zone of the sea, of course, taking into account the wave impact and overburden phenomena.
As for the foreseeable future, it can be expected that the lowering of sea level will gradually stop. There is a limit to evaporation, reduction of water resources. There is a high probability that in the near future the rate of decline of the level will slow down, it will stabilize at a level closer to -30 m and then its gradual rise will occur.
– How does the lowering of the Caspian Sea level affect the fauna of this unique reservoir?
– In general, the impact on the marine ecosystem is insignificant. From a natural-historical point of view, the lowering of the level in the 30-70s of the XX century did not cause any environmental catastrophe, nor does the current decline.
– What should be particularly disturbing in connection with the shallowing?
– The volume of water intake on the Volga River, the construction of a reservoir on the Ural River led to a halving (from 9.5 km3 on average to 5 km3) of the inflow of water into the sea, the same thing happens with our Kura. And since 2011 to this day, the inflow of water volumes to the Caspian has fallen from 16 km3 to 5-6 km3. Plus, the outflow of water into the Kara-Bogaz-Gol Bay in the west of Turkmenistan “takes” 5-7 cm from the water level every year. All of these factors have a negative impact on the Caspian Sea. Of course, we should not forget about global climate change, it is becoming more and more arid, so evaporation from the surface of the Caspian Sea is increasing.
– Is it possible to do something to improve the situation?
– Following the international convention on the Caspian Sea, it is necessary to monitor the regulation of river flow, that is, the water resource of rivers flowing into the Caspian. And it is also necessary to control the flow of reservoirs, of which there are many on the Volga, Ural, Terek, Kura, etc. rivers. If they did not exist, the water level in the Caspian Sea would be 2.5 m higher than today. It is clear that water is needed for water supply, irrigation, electricity generation, etc. However, water resources must be used rationally. It is equally important to regulate the flow into the Kara-Bogaz-Gol Bay, which I have already mentioned, especially since its salt resources are not being used now. In the 1980s, it was blocked by a dam that blocked the flow of water from the Caspian Sea. But in the 1990s, the bay was reopened, as the sea level then rose significantly.
It is important that the necessary efforts be made by all the Caspian littoral States. It is necessary to do everything possible so that the Caspian Sea avoids the sad fate of the Aral Sea. I believe that it is a transboundary water body and it should be treated accordingly to its status. The Caspian countries should decide on the regulation of the inflow of river water into the sea, limits or risk levels, conduct large-scale studies on the possibility of transferring the flow of northern rivers into the Caspian Sea through the tributaries of the Volga basin and other possible ways to maintain the water level above -30 m from the level of the World Ocean.