The decline in the Caspian Sea's water level has become one of the most serious environmental challenges facing the region in recent years. The retreat of the water may alter coastal areas, wetlands, and shallow-water zones, reducing the habitats of fish and other aquatic species. This process could negatively affect biodiversity and disrupt the natural balance of coastal ecosystems. In the long term, it may lead to declining fish stocks, shifts in the distribution of certain species, and increased vulnerability of ecosystems.Speaking to Ekologiya.az, Said Safarov, Head of the Caspian Sea Geography Laboratory at the Institute of Geography of the Ministry of Science and Education of Azerbaijan and Doctor of Geographical Sciences, stated that the Caspian Sea level is continuing to decline.“According to most forecasts, the Caspian Sea's water level will continue to fall over the coming century. Under the worst-case scenario, if the Paris Agreement is not fully implemented, the sea level could decline by approximately 18 meters by the end of the century. However, if decisive measures are taken to combat global warming by reducing carbon dioxide and other greenhouse gas emissions, the outcome could be less severe.

Even if emissions stopped increasing today, a significant amount of carbon dioxide has already accumulated in the atmosphere, meaning that warming will continue to some extent. Under the more optimistic scenario, in which the Paris Agreement is successfully implemented, the Caspian Sea level is expected to fall by around 9 meters by the end of the century.

This does not mean that the sea level will decrease continuously in a straight line. There may be periods when the level temporarily rises, but the overall long-term trend will remain downward. Therefore, by the end of the century, the total decline is expected to be between 9 and 18 meters.”

Safarov explained that a lower sea level also means a reduction in the total volume of water in the Caspian Sea.

“As the volume of water decreases, the concentration of dissolved and suspended pollutants increases. If the amount of pollution remains the same while the water volume shrinks, contamination becomes much more concentrated. This creates unfavorable conditions for fish and other marine organisms.

Furthermore, in coastal areas, lower water levels combined with global warming cause the water to heat up more quickly. Warmer water contains less dissolved oxygen, making it difficult for aquatic life to survive. Plankton, which forms the foundation of the marine food chain, is also negatively affected. All of these factors have a harmful impact on the Caspian Sea’s biodiversity.

Another major threat is continuous pollution. The population living around the Caspian Sea has increased significantly over the past 30–50 years. For example, the population of the Absheron Peninsula has doubled or even tripled over the last few decades. Similar trends can be observed in Russia, Kazakhstan, Turkmenistan, and Iran. Naturally, a growing population produces more wastewater, much of which eventually reaches the Caspian Sea.”

According to Safarov, recent research indicates that the main factor influencing the Caspian Sea's water level is river inflow, particularly from the Volga River.

“For this reason, river water must be used much more efficiently and responsibly. Water waste should be minimized. Solving this issue could partially slow the decline in the Caspian Sea's water level.

Another major issue is pollution. The five Caspian littoral states need to cooperate to ensure that wastewater entering the sea through rivers, canals, and drainage systems is properly treated before being discharged. This would help protect fish and other aquatic organisms.

Although fish-restocking programs exist, with sturgeon and other species being released into the sea, it is extremely difficult for them to survive in polluted waters.

Climate change has also seriously affected the Caspian seal population. These seals breed on ice in the northern part of the sea, but global warming has reduced the extent of ice-covered areas. Combined with illegal hunting, pollution, and other human activities, this has caused a dramatic decline in their numbers.

While the Caspian seal population once exceeded one million, it has now fallen to around 100,000. International cooperation has addressed these issues through agreements such as the Tehran Convention, signed by the five Caspian countries to improve environmental management and reduce pollution. Although several meetings and decisions have followed, the results have not yet been sufficient to reverse the current trends.”