The water level in the Caspian Sea has declined since 2006 and reached its critical point in 2022. Authorities of Kazakhstan believe that shrinking world’s largest inland (isolated from the world ocean) body of water is the result of climate change: rise in air temperature, absence of precipitation, and reduced inflows from rivers.
Islands have appeared
The sharp shrinking of the Caspian Sea has been observed by Aktau residents back in 2016.
“Until then, everyone was aware that the sea receded. But what happens now has never been seen previously. Now we see that in some places the sea receded by several metres,” said Azamat Sarsenbaev, public figure based in Aktau.
According to Sarsenbaev’s observations, new islands have appeared because of the water level decline. The sea has moved dozens of meters away from the city, and kilometres away from the northern coast.
“The decline in the sea level by more than one metre contributed to the Caspian Sea shoreline changes, especially in the Kazakhstan sector. It can be explained by the fact that the given area of the sea has mild slopes of the seabed and adjacent shoreline, and even small changes in the sea level contribute to significant flooding or shrinking of the coast. During the period, the area of the body water declined by more than 22 thousand square kilometres, and over a half of them belong to the Kazakhstan section of Northern Caspian Sea,” according to the Ministry of Ecology of Kazakhstan.
Shrinking of the Caspian Sea, according to Azamat Sarsenbaev, is related to the degradation of two main rivers feeding the sea: the Zhaiyk (Ural – Author’s note) and the Volga.
“In my opinion, the main reason is that these two rivers are overexploited. After the collapse of the Soviet Union, many dams have been built on these rivers, their waters are used for agriculture, cities are located along the Zhaiyk and the Volga, which feed them,” Sarsenbaev said.
Kirill Osin, ecologist and director of non-governmental institution “EcoMangistau”, said that one of the reasons of the deplorable state of the Caspian Sea was shrinking of rivers.
“This (shrinking of rivers) is affected by climate change. Rivers receive less water in a natural way, plus there is a factor of irrational use of water, silting of riverbeds,” Kirill Osin said.
Ministry of Ecology and Natural Resources of the Republic of Kazakhstan share the opinion of public activists regarding the deterioration of rivers feeding the Caspian Sea. According to them, the Volga feeds over 90 per cent of water to the Caspian Sea and runs in the territory of the Russian Federation. The Zhaiyk feeds no more than 2 per cent. However, the Zhaiyk plays an important role in reproduction of fish resources of the Caspian Sea. Because of the low water period, the river flow has declined by 50-60 per cent, which has led to degradation of spawning sites and the river’s ecological state.
To improve the situation, Kazakhstan and Russia have signed the “Integrated Roadmap for Active Cooperation in the Studies of Basins of Rivers (Zhaiyk, Yertis and others)”. According to the Ministry of Ecology of the Republic of Kazakhstan, they are gathering and analysing data, and deadline is the end of 2023.
Low precipitation, high evaporation
In the last century, scientists reported that the level of the Caspian Sea either declined, or increased for decades. The first cases of shrinking were observed in 1930 to 1941. In this period, the sea level declined from -26.07 metres BHS (Baltic Normal Height System – author’s note) to -27.85 metres BHS due to large-scale climate changes. In further years, shrinking took place at a slow pace, and in 1960s the water level stabilised at the level -28.4. In the first half of 1970s, the level declined to the extremely low level in the last 150 years, i.e. -29 in 1977. This period caused shoreline change and desertification of coastal areas.
The Caspian Sea level began to rise sharply since 1978, and by 1995 it rose by 2.5 metres and reached the level of -26.62 metres BHS. The average pace of rise in the sea level in this period was about 14 cm per year, and in some years up to 36 cm. In 1995, the rise in the sea level slowed down, and tends to decline since 2006. In 2022, its level reached -28.7 metres BHS.
Kirill Osin focuses on the fact that the main reason behind shrinking of the Caspian Sea today is climate change, which affects the increased evaporation of the water body and the water fails to return in a natural way via precipitation.
According to specialists of the Ministry of Ecology of Kazakhstan, fluctuations in the Caspian Sea level are complex and the climatic factor mainly affects the body of water: climate change, increase in the average annual temperature of air, faster precipitation, and reduced river discharge, which affects the water balance of the Caspian Sea.
“From 2006 to 2022, there was the lowest precipitation in the Caspian Sea region, while evaporation rates were high. The average flow rate was low because of several dry years in the Volga River basin. In 2021, the ambient sea level reached -28.43 metres BHS, and in 2022 the level declined by 27 cm and reached the level of -28.7 metres BHS. Thus, the sea level drop rate increased in 2022 compared to 2021, when the average rage was 20 cm per year. The main reason was the reduced flow rate of Volga river in 2022, i.e. 212 cubic kilometres, which was substantially below normal, which is 238 cubic kilometres, and is comparable to the flow rate in 2021 (208 cubic kilometres),” according to the Ministry of Ecology of Kazakhstan.
According to the agency, the current sea level has reached the level of -28.7 metres BHS, which is 20 cm below the critical level.
“Drop in the sea level to the level of -28.5 metres, given the history of the Caspian Sea, is critical for both its ecosystem and marine sector,” according to the Ministry of Ecology of the Republic of Kazakhstan.
“Specific actions needed”
According to Kirill Osin, the current level of shrinking of the Caspian Sean cannot be called critical, yet we should keep abreast of the developments, namely monitor the sea level, carry out joint cross-border operations to restore rivers, address water conservation issues. However, he does not see any specific actions.
“I don’t see today that any significant measures are being taken. There are only speeches by the presidents and the government, yet no instructions or decisions follow. However, ‘water diplomacy’ should have started working with the Russian part of the Volga River a long time ago. The Caspian Sea has a cyclic behaviour, yet we should keep an eye on it,” Osin said.
The ministry of ecology cites the long-term forecast of the Caspian Sea level prepared by state enterprise “Kazgidromet.” Thus, according to the “moderately severe” and “severe” climate scenarios, the sea level can reach -29.23 metres BHS and -29.63 metres BHS, respectively, by 2030. According to Osin, there are various forecasts until 2100 predicting that the level would decline from 9 to 16 metres, and there are positive forecasts predicting that the sea level would increase substantially.
“Such models use a variety of different factors, and forecasts are different, as well,” Kirill Osin said. “But we should start works to adapt to climate change as soon as possible.”
In November 2022, President of Kazakhstan Tokayev gave instructions to establish a state research institute for carrying out the Caspian Sea researches, but it has not been established so far. It is planned to be opened at the end of 2023.