Drying of the Aral Sea reshapes the anthropogenic carbon inventory of Central Asia

[Geoengineering News]

https://www.science.org/doi/10.1126/science.aeb2344

Authors: Rafael Marcé, Daniel Diaz de-Quijano, Sofía Rodríguez-Gómez, Enrique Moreno-Ostos, et al.

16 July 2026

DOI: 10.1126/science.aeb2344

Editor’s summary

The Aral Sea, once the fourth largest inland water body in the world, now contains the world’s largest exposed dry lake bed due mostly to the diversion of its two main feeding tributaries for irrigated agriculture. What have been the consequences of this drying on the large stores of carbon contained in its sediments? Marcé et al. showed that the Aral Sea has changed from a carbon sink to a carbon source and quantified the loss of organic carbon from these sediments since the lake began shrinking in the early 1960s. Carbon emissions from the remaining submerged sediments could be three times what have occurred already if they too become desiccated. —Jesse Smith

Abstract

Lakes store large quantities of carbon in their sediments, contributing to climate regulation. Yet the fate of this carbon after lake desiccation remains unclear. Using a space-for-time substitution approach, combining sediment cores, carbon dioxide flux measurements, and remote sensing, we quantified organic carbon losses from the world’s largest desiccated lake, the Aral Sea. Since 1960, exposed lake bed sediments have released 204 ± 53 teragrams of carbon (Tg C), with vegetation growth offsetting less than 1%. Incorporating these emissions alters the regional carbon budget, transforming the Aral Sea basin from a presumed land-use-change carbon sink into a net source. Reflooding the sea could prevent an additional 165 ± 13 Tg C release, reframing restoration not only as an ecological and humanitarian imperative but also as a climate mitigation opportunity.

Source: Science