The Caspian is falling faster than its ports can dig

The Caspian Sea has been falling since the mid-1990s, and the three states with the most at stake are now paying for it in dredgers, reduced ferry loads and new research programmes. What they have not done is agree on why it is happening or on anything that would slow it. For now, the governments are treating the decline as an engineering problem at the ports and a data problem at sea. The projections suggest it will turn into a problem of what those ports are for.

What the gauges show

Kazakhstan publishes the most detailed recent figures. Its ministry reported in March 2026 that the sea averaged minus 29.35 metres against the Baltic height datum across the Kazakh sector in 2025. The north-eastern Caspian averaged minus 29.23 metres and the eastern sector minus 29.47 metres. In parts of the Kazakh coast, the shoreline moved 30 to 35 kilometres seaward between 2006 and 2025. The ministry attributes the decline to climate change, higher evaporation, lower river inflow and economic activity, without weighting them.

These readings put the sea at or below its previous twentieth-century low. Kazakh officials cited in mid-2025 a level of minus 29.21 metres, against a 1977 trough of minus 29.24 metres. The Caspian has swung before: Russian government material notes that the level fell by about 3 metres between 1930 and 1977 and then rose by 2.4 metres from 1978 to 1995. That history is the basis of Moscow’s caution about long-range forecasts. It is also why a decline of this length does not settle the argument on its own.

Kazhydromet’s scenarios, prepared in 2020 and restated by the ministry this year, have the sea at minus 29.8 metres by 2030 in the optimistic case and minus 30 metres in the pessimistic one. By 2050 the range is minus 32.4 to minus 34 metres. That is a further 3 to 5 metres below today’s level.

Why the Volga is the disputed variable

The Volga supplies the large majority of the river water entering the Caspian, so any account of the decline runs through it. Kazakhstan’s water ministry has estimated that stabilising the sea needs about 279 cubic kilometres a year of river inflow, at least 275 of it from the Volga. By the ministry’s estimate, 2023 inflow fell 60 to 65 cubic kilometres short of that. Deputy minister Bolat Bekniyaz said in 2025 that Astana hoped to cooperate with Russia "on a legal basis" over the Volga’s flow, which is regulated by a cascade of hydropower reservoirs.

The legal ground is narrow. The Volga lies entirely within Russia, unlike the Ural (Zhaiyk), which is covered by an intergovernmental agreement. The Kazakh–Russian working group created in 2025 deals with floods on shared rivers, not with the Volga. Russian specialists have also contested the premise. Stanislav Pritchin of the Russian Academy of Sciences called Kazakhstan’s demands "excessive", noting that no new reservoirs or large withdrawal projects are under way in the basin. The hydrologist Mikhail Bolgov argued that the sea has a "memory" of 50 years or more, which makes it unrealistic to manage the level through a single variable. Russia’s natural resources ministry frames the decline as a question of climate change that needs further study.

Both readings can be partly right. Lower Volga flow and higher evaporation are not rival explanations: the first is itself partly a product of warmer, drier conditions in the basin. The disagreement matters because it decides who is expected to act. If the cause is regulation upstream, Kazakhstan has a claim on Russian water management. If it is climate, every littoral state is adapting to the same loss.

What the governments are doing

Kazakhstan has moved furthest on the ports. China Harbour Engineering Company is the main contractor for dredging at Aktau. According to Kazakhstan’s transport ministry, main works were due to begin in the second half of July 2026 and finish by the end of the year, with the navigable draft deepened to 6–7 metres. Figures compiled by the Times of Central Asia put Kazakhstan’s dredging and berth budget at roughly $179 million across Kuryk ($56.8 million), Aktau ($39.8 million for dredging and $65.2 million for berths) and Bautino ($17.6 million). Astana has also set up a Caspian research institute and expanded monitoring from 2026.

Azerbaijan’s main port is on a slower timetable. Eldar Salahov, director general of the Port of Baku, said in September that an international dredging tender held over the summer was being evaluated. He expected physical work in the Azerbaijani sector to start by the end of 2026 and to last about 18 months. The state shipping company ASCO reports the effect at sea: its sustainability director, Alakbar Azizli, said a ferry from Kazakhstan can now carry only 80 per cent of a full load, which means "20% less cargo is transported".

Russia has chosen study before commitment. In June 2026 the government tasked the natural resources ministry, other federal agencies and regional authorities with a comprehensive programme on the sea’s changing level, due by the third quarter of 2027. It is to cover the water balance, the effects on fish stocks and fisheries, and a method for forecasting the level and its economic consequences, with adaptation recommendations for federal and regional authorities. Minister Alexander Kozlov said in 2025 that forecasts over several years hold up but forecasts over decades are "unfortunately unreliable".

What the science projects

The long-range studies are less cautious than the governments. Rohit Samant and Matthias Prange of the University of Bremen used CMIP6 climate models to project a fall of about 8 metres by 2100 under a medium-emissions pathway, with a model range of 2 to 15 metres. Under high emissions the fall is about 14 metres, with a range of 11 to 21. The driver is evaporation from the sea surface, which rises faster than rainfall across the catchment. At the upper end of these ranges, the shallow northern basin and the Kara-Bogaz-Gol bay would dry out completely.

A 2025 study led by Rebecca Court and colleagues shows what that means for ecology. A 5-metre decline would turn about 77,000 square kilometres of sea into land, around a fifth of today’s surface. It would remove 57 to 81 per cent of the Caspian seal’s breeding habitat. Sturgeon would lose 25 to 45 per cent of their summer and autumn range, depending on the scenario. Under a 10-metre decline, marine protected areas would shrink from 16.8 per cent of the sea to 1 per cent as the water retreats from them. The authors add that ports such as Baku, Aktau and Turkmenbashi, along with offshore oil facilities, would be left stranded.

Kozlov’s scepticism and these projections are not as far apart as they look. The model range is wide, and the natural swings of the twentieth century were large. But none of the scenarios cited here has the sea recovering to the levels its ports were built for, and even the optimistic Kazakh case has it falling another metre by 2030.

What to watch

Dredging at Aktau and Baku will restore draft for a few years. At the rates Kazakhstan and Azerbaijan report, though, it will have to be repeated, and is likely to cost more each time as channels lengthen across a retreating shelf. The question for port authorities and the corridor’s financiers is whether to keep deepening existing basins or plan for berths further offshore. That choice has to be made on the scientific range, not on the most recent gauge reading.

Three things will show whether the littoral states are moving beyond measurement. The first is whether Russia’s 2027 programme includes Volga reservoir operations or treats climate as the only input. The second is whether the joint programme the five states agreed under the Tehran Convention in September, which Russia’s ministry describes as monitoring, information exchange and pollution control, grows to cover the water level. The third is whether Kazakhstan and Russia’s commitment in their May 2026 joint statement to joint management of water and Caspian issues produces a body with a mandate over the Volga, rather than over floods alone. Until one of these happens, each state will keep dredging its own ports, and none of them will be addressing the causes of the decline.

Sources

• The Astana Times — Kazakhstan Reports Caspian Sea Level Decline, Outlines 2050 Scenarios
• Renewable Matter — The Caspian Sea is drying up, and Kazakhstan asks Russia to collaborate in managing the Volga River
• OSN — Правительство утвердило комплексную программу мониторинга Каспийского моря
• Dredging Today — CHEC gears up for Aktau Port dredging
• Dredging Today — Caspian Sea dredging on the way, Baku Port CEO says
• The Times of Central Asia — Shrinking Caspian Sea Raises the Cost of the Middle Corridor
• Communications Earth & Environment — Samant and Prange, Climate-driven 21st century Caspian Sea level decline estimated from CMIP6 projections
• Communications Earth & Environment — Court et al., Rapid decline of Caspian Sea level threatens ecosystem integrity, biodiversity protection, and human infrastructure