The Caspian Sea has been shrinking for decades. Now, a new island has emerged

Scientists warn that parts of the northern Caspian could face an Aral Sea-like scenario, while climate change and human water use are adding pressure on the region. The Caspian Sea is the largest inland body of water on Earth, but for years it has been shrinking. The northern and north-eastern parts along Kazakhstan's coast form the shallowest sector of the Caspian Sea, typically ranging between just three and six metres. But as water levels continue to fall, following decades of climate change and human activity, environmentalists are discovering clusters of under-water islands. The latest was spotted days ago near Kulaly Island during a recent aerial survey. Volunteer and environmental activist Daniyar Akimzhanov was part of the group that reported the discovery. He says that the newly emerged island is relatively small, but it is far from an isolated case. In fact, over the past four to five years, Akimzhanov says he has documented several new islands in this part of the Caspian Sea. “The one in the photo I sent you is the smallest. There are much bigger new islands,” he explains. The Caspian Sea's secret islands Some stretch around one kilometre in length and 200 to 300 metres in width and wildlife has already begun reaching the newly exposed land. Akimzhanov says he personally spotted a wild boar on one of the islands, while wolves also make their way there across the ice. The newly emerged islands usually do not get names, he says. The Kazakh Research Institute of the Caspian Sea, which began work in September 2025 after being established on the instructions of President Kassym-Jomart Tokayev, says more areas of land are likely to emerge. However, not all of them will become permanent islands. “The future of each newly exposed area depends on the seabed topography, waves, wind-driven changes in water levels and the subsequent dynamics of the Caspian Sea level,” the institute says. The emergence of new islands is one of the most visible signs of a much broader transformation: the Caspian Sea is retreating. The Caspian Sea is retreating The Caspian Sea is the world's largest landlocked body of water. It is bordered by five countries: Kazakhstan, Russia, Azerbaijan, Iran and Turkmenistan. More than 80 per cent of its river inflow comes from Russia’s Volga River. Dr. Sifan Koriche, a hydroclimate scientist at the University of Alabama who has published several studies on the Caspian Sea, explains its water balance in simple terms. “It's like a simple water balance. The incoming water is from river inflow and precipitation, while the outgoing water is only through evaporation,” he says. According to instrumental observations, the Caspian Sea level in the Kazakh sector fell from -26.82 metres in 1996 to -29.27 metres in 2025. This represents a decline of 2.45 metres over the past three decades, or an average of around 8–9 centimetres per year. The decline has continued. According to the Kazakh Research Institute of the Caspian Sea, the average sea level at the Kulaly Island monitoring station stood at -29.42 metres as of July 2026, the lowest level recorded during the entire study period. The north-eastern Caspian, including the coast of Kazakhstan's Atyrau region, is particularly vulnerable to falling water levels. With an average depth of around six metres and a very gentle seabed slope, even a relatively small drop in water level can cause the shoreline to retreat over long distances. The scale of the retreat is already visible. According to the Kazakh Research Institute of the Caspian Sea, between 2000 and 2025, the area covered by water in the studied part of the north-eastern Caspian decreased by around 16,384 square kilometres. Satellite images analysed by the institute also show how the coastline has changed in recent years. Between 2021 and 2026, falling water levels gradually exposed new areas of seabed near Kulaly Island and the Tyuleniy Archipelago. The Caspian has historically experienced periods of both falling and rising water levels. From the 1930s to 1977, its level dropped by around three metres. Over the following two decades, it rose again by about 2.5 metres, before beginning another period of decline. But while fluctuations in the Caspian Sea level are not new, scientists say climate change and human activity are now affecting its water balance. Previous research has linked the decline in recent decades mainly to increased evaporation from the Caspian Sea as regional temperatures have risen. A decrease in precipitation has also contributed, but to a smaller degree. Human activity also affects how much water reaches the Caspian. Dams regulate the rivers flowing into the sea, while water is extracted across the basin for irrigation and other uses. The way reservoirs are managed can also affect river flows reaching the sea. Why Caspian seals are declining The Caspian seal, found nowhere else in the world, has already undergone a dramatic population decline. Over the past 100 years, its population has fallen from around one million to about 100,000. The retreating sea is adding pressure on the species by transforming the isolated islands it uses as seasonal haul-out sites. According to seal researcher Assel Baimukanova, the area of island haul-out sites has decreased more than 15-fold since 1995. In 2021, Baimukanova and other researchers from the Institute of Hydrobiology and Ecology stayed on a small newly formed island they called New Durnev, where thousands of seals gathered. When they returned in 2023, the island had expanded significantly and could at times be reached by car. It later connected to the mainland. “For seals, it became inaccessible. No isolated island means no seals,” Baimukanova said. As the sea retreats, seals are also being pushed westwards. The north-eastern Caspian had long served as a natural refuge for the animals because it was difficult for people to access. Further west, seals face more human activity, including fishing, shipping, tourism and oil and gas operations. Warming temperatures pose another threat to the seals: the loss of stable winter ice. Caspian seals give birth on ice, but Baimukanova says warmer winters are making it thinner and less stable. The effects of the retreating sea go beyond wildlife. The Kazakh Research Institute of the Caspian Sea says shrinking shallow waters are also affecting wetlands and could pose growing challenges for fisheries, ports, shipping and other coastal infrastructure. What happens next? Most climate scenarios suggest that the Caspian Sea will continue to decline during the 21st century, although scientists stress that the exact scale remains uncertain. Koriche's research projects a decline of up to eight metres by the end of the century under an intermediate climate scenario, although results vary significantly between models. To illustrate what even a smaller decline could mean, Koriche says a five-metre drop could expose around 77,000 square kilometres of seabed in the northern Caspian. Koriche says the entire Caspian is not facing an Aral Sea-like scenario because its central and southern basins are much deeper. But parts of the shallow northern Caspian could face significant desiccation. “The northern part covers a quarter to one third of the water body. There is a chance that this northern region could face a scenario similar to the Aral Sea,” he says. But the scale of the future decline is not predetermined. Koriche's research suggests that human water extraction could add up to seven metres to the decline under some scenarios. He says measures should focus both on slowing the decline and adapting to it. This includes better management of water use across the Caspian basin, particularly the Volga, as well as stronger monitoring and data sharing between countries. The Kazakh Research Institute of the Caspian Sea also says adaptation is becoming increasingly important. Measures include protecting vulnerable ecosystems, monitoring newly exposed seabed and adapting ports and other coastal infrastructure. Some regional initiatives are already underway. Kazakhstan has proposed an interstate programme to conserve the Caspian Sea's water resources, while the five Caspian states are also working on a 2026–2036 action plan under the Tehran Convention to improve monitoring, assess the impacts of sea-level changes and develop adaptation measures. “Effective solutions are only possible through coordinated action by all five Caspian states,” the institute says.