The drying of the Aral Sea has created another environmental problem: according to a study, exposed lakebed sediments released about 748 million tons of CO2 into the atmosphere between 1960 and 2022. Organic carbon remains stored in the sediments, and restoring part of the water cover could prevent the release of another 605 million tons of CO2. This gives efforts to restore the Aral Sea region a new climate dimension.
The study, conducted by an international team of researchers led by scientists from Spain’s Centre for Advanced Studies of Blanes (CEAB-CSIC), was published in Science on July 16.
The findings add another consideration to restoration efforts already underway across the region, from refilling part of the sea in Kazakhstan to planting saxaul and rehabilitating degraded land in Uzbekistan.
The Aral Sea’s Carbon Legacy
When the Aral Sea was still a fully-fledged body of water, plants and algae absorbed carbon dioxide, while some organic matter settled on the lakebed. As the water retreated, those sediments were exposed to the air, organic matter began to decompose, and the stored carbon started returning to the atmosphere as CO2.
At the same time, winds carry salt and dust from the newly formed Aralkum Desert, spreading the consequences of the sea’s disappearance far beyond its former shoreline.
In 2022, researchers conducted an expedition to the dried Aral Sea bed, collecting sediment samples and measuring how much CO2 was being released. Combined with satellite data, this allowed them to estimate carbon losses as the sea retreated.
According to the researchers’ calculations, exposed sediments lost about 204 million tons of carbon between 1960 and 2022, equivalent to roughly 748 million tons of CO2. New vegetation growing on the dried lakebed has offset less than 1% of those emissions.
A significant amount of organic carbon remains in the sediments. The researchers estimate that restoring water cover could prevent the release of another 605 million tons of CO2.
The authors also considered the economics of such an effort. Using 2024 voluntary carbon market prices for land-use and forestry projects as a benchmark, they estimate that the avoided emissions could potentially be worth $3.6 billion to $18 billion in carbon credits.
That money could theoretically become one source of funding for ecosystem restoration. Researchers estimate that about $9.7 billion in water-management improvements could increase inflows enough to restore roughly half of the area covered by the Aral Sea in 1960, while potentially generating about 323 million tons of CO2-equivalent carbon credits.
Restoring the Entire Aral Sea Is No Longer the Goal
Under current conditions, fully restoring the sea is widely considered unrealistic. The central issue is water.
The Amu Darya and Syr Darya flow through several Central Asian countries. Significantly increasing the amount of water reaching the Aral Sea would be impossible without basin-wide agreements, irrigation modernization, and reductions in water losses.
This is why restoration of the Aral Sea remains a regional issue rather than solely an Uzbek or Kazakh one. Central Asian countries coordinate part of this work through the International Fund for Saving the Aral Sea. Uzbekistan is due to chair the fund in 2027–2029.
At the same time, parts of the former sea show that localized recovery is possible. Kazakhstan continues efforts to restore the North Aral Sea, where the volume of water has increased to about 23.5 billion cubic meters.
In the south, the approach is different. Efforts there focus primarily on stabilizing the exposed lakebed and improving living conditions for local communities by reducing salt and dust storms and restoring degraded land.
Saxaul Against the Aralkum
Planting saxaul has become one of the main tools. Saxaul is a drought- and salt-resistant desert shrub native to Central Asia. Its roots stabilize loose soil and reduce the movement of sand, salt, and dust.
In Kazakhstan, afforestation work on the dried seabed has already covered about 1.2 million hectares.
In Uzbekistan, one such effort is the Green Aral Sea initiative. In March 2025, the United Nations Development Programme, together with local environmental and forestry agencies, completed another stage of planting, putting 80,000 saxaul seedlings into the ground across 80 hectares in the Muynak district.
Conditions on the former seabed are harsh: highly saline soil, extreme temperatures, little rainfall, and frequent sandstorms. Researchers and environmental organizations are therefore also testing methods to improve plant survival.
In some areas, seedling roots have been treated with mixtures of liquid manure and clay to retain moisture. Since 2024, a Japanese water-retaining product known as SAP has also been tested.
According to UNDP’s latest figures, its Green Aral Sea crowdfunding platform has planted 915,840 salt- and drought-tolerant trees across 763.9 hectares of exposed seabed. The initiative itself remains small compared with the territory affected by the disaster: the Uzbek part of the dried seabed covers about 2.7 million hectares.
Beyond Afforestation
The work is no longer limited to saxaul planting. In August, UNDP announced the Aral Sea Wetlands Innovation Challenge 2026, a $40,000 program funding pilot projects to restore degraded and saline land. In June, UNDP and the Karakalpakstan authorities had already agreed to expand cooperation on land, water, and ecosystem restoration in the Lower Amu Darya and Aral Sea region.
Uzbekistan also adopted a state development program for the Aral Sea region in 2017, while between 2021 and 2024 the Global Green Growth Institute implemented a $5.9 million program in Karakalpakstan focused on climate-smart agriculture and green finance.
A New Dimension to the Aral Sea Crisis
Until now, the consequences of the Aral Sea’s disappearance have usually been measured in lost water, millions of hectares of desert, salt and dust storms, and the damage inflicted on local communities. The new research adds carbon to that list.
Restoring the Aral Sea to its former state may be unrealistic, but the study suggests that partial reflooding could prevent substantial additional carbon emissions while complementing efforts to stabilize the exposed seabed. It also raises the possibility that carbon finance could eventually help pay for some of that work.
