Concern has been growing in recent years over the steadily declining level of the Caspian Sea, the world’s largest inland body of water. The water level dropped by about two meters from 2006 to 2024, having begun to decline in 1995. It has now reached its lowest recorded point of 29 meters below sea level, and experts forecast that the level will continue to drop. By the end of the twenty-first century, the water level is predicted to fall by 9 to 18 meters, which would reduce the sea’s total area by a quarter.
While all parts of the Caspian Sea are exposed to the danger of desiccation, the northeastern sector belonging to Kazakhstan will be the first to be affected. The depth is shallowest there, and this, along with hydrocarbon and shipping activities in the area, makes this part the most vulnerable.
The Caspian Sea’s falling level is driven by multiple factors including the regulation of river inflows, desalination, and hydrocarbon contamination. The primary cause, however, is climate change, which has led to reduced precipitation and increased evaporation across the drainage basin, exacerbating water loss.
Normally, sea levels rise under the influence of climate change. But the Caspian Sea, as a closed body of water fed by rivers, is experiencing the opposite effect. The average annual surface air temperature over the sea increased by around one degree between 1979 and 2015. This rise in air temperature and the changing wind direction have significantly increased the evaporation of water in the basin. According to a UNEP report, particularly high levels of evaporation are causing the Caspian Sea’s level to continuously fall.
Climate change is a direct outcome of anthropogenic activities such as fossil fuel use. The Caspian Sea is rich in these resources, accounting for 48 billion barrels of oil and 292 trillion cubic meters of natural gas. This has prompted the littoral states of the Caspian Sea to actively develop the hydrocarbon industry in their sectors of the sea.
The impact of fossil fuel production on water levels is especially pertinent to the northern part of the sea surrounded by Kazakhstan and Russia. While the middle and southern parts of the Caspian Sea comprise about one-third and two-thirds of the total water volume, respectively, the northern part accounts for just one percent.
Twenty-nine percent of the Caspian coastline is in Kazakhstan. From 2001 to 2022, the surface area of the northeastern part of the Caspian Sea declined by 39 percent, while the shore retreated by 37.25 kilometers. If the water level drops by 10 meters, the distance between the shoreline and coastal settlements in the northeastern sector will be the largest on the Caspian Sea, reaching 89 kilometers.
The situation is being exacerbated by oil companies operating in this part of the sea. As well as being the shallowest part, the northeastern sector encompasses the largest amount of both offshore and onshore fossil fuel reserves of the Caspian Sea. In 2013, Kazakhstan’s oil reserves in the sea amounted to 31.2 billion barrels out of a total of 48 billion barrels, while natural gas reserves were equal to 104 trillion cubic feet out of 292 trillion cubic feet, according to a report by the U.S. Energy Information Administration.
There are two main oil fields in the Kazakh sector of the Caspian Sea: one onshore (Tengizchevroil) and one offshore (Kashagan). These oil projects have been exploited by Kazakhstan in cooperation with foreign companies, during which environmental violations have been recorded. Weak enforcement mechanisms for both Kazakhstan’s environmental legislation and the Caspian environmental institutions (the Tehran Convention and its protocols) enable companies to get away with causing environmental damage to the Caspian Sea. Noncompliance with environmental provisions leads to more greenhouse gas emissions and accelerates the drop in the Caspian Sea’s water level even further.
Another major factor causing greenhouse gas emissions in the northeastern sector of the Caspian Sea is shipping. In 2012, emissions from shipping accounted for 2.2 percent of global anthropogenic emissions of carbon dioxide. In addition, shipping can impact the environment through oil spills.
There are two main ports in the northeastern Caspian—Aktau and Kuryk—serving the shipping industry. Fifteen million tons of oil are transported through these ports each year. As shipping increased, fifteen oil spills were recorded in the vicinity of the ports from 2013 to 2022. However, according to a study conducted by German and Mongolian scientists, the number of oil spills was actually as high as 329. Scientists say that shipping was the primary source of oil pollution in those areas. Based on the shapes of the spills, they are believed to be the result of ship discharges: presumably of ballast water or waste.
In the last few years, cargo volume has soared along the Trans-Caspian International Transport Route, also known as the Middle Corridor, which extends across land and sea to connect China with Europe. From China, goods cross Kazakhstan by rail to Aktau Port, where cargo is transferred to vessels that cross the Caspian Sea to the Port of Baku, and is subsequently sent to Europe via Georgia and Türkiye.
The importance of the Middle Corridor has grown significantly since Russia’s invasion of Ukraine, because it represents an alternative to the Northern Corridor, which links European markets to China through the territory of Russia. The World Bank estimates that by 2030, cargo volume transported through the Middle Corridor could reach 11 million tons, of which 4 million tons will create demand for container transport in the Caspian Sea. This will further increase carbon dioxide emissions and thus the evaporation rate of the water.
The failure to address the environmental impact of the hydrocarbon and shipping industries can be explained by the high revenues generated by these sectors for the littoral states. Direct financial payments from Tengizchevroil to Kazakhstan in 2024 amounted to $8.4 billion, while the Middle Corridor, according to the World Bank, “has largely been dominated by Kazakhstan’s exports.”
Though these industries play a vital role in the state’s economy, the cost of overlooking their impact on the Caspian environment will be high. It could turn into a vicious circle in which the falling Caspian Sea level starts to jeopardize the operations of the fossil fuel and shipping industries. It is important, therefore, that both industry operators and officials in the Caspian Sea’s littoral states recognize the seriousness of the issue and take comprehensive measures to address the anthropogenic reasons for the water level’s decline.
