The Aral Sea. The impact of irrigation and agriculture on natural heritage

By Luca Bolognesi

What is this story about? 

The Aral Sea was one of the largest natural lakes of the world and an important natural heritage for millions of people who lived along its shores for millennia. However, from the 1960s onwards, large scale economic development initiatives promoted by the Soviet Union in underdeveloped regions resulted in a major ecological disaster. The two main rivers providing water to the lake were diverted to provide water for irrigating previously desert areas. This brought, over a few decades, to the almost complete disappearance of the Aral Sea and had substantial consequences on the natural and cultural heritage of the region.     

A millenary history

The Aral Sea was the fourth-largest lake in the world, a rich and beautiful environment where fauna, flora, and both large and small communities of humans thrived. It is located in Central Asia, between Kazakhstan in the North and Uzbekistan in the South.

Formed over 5.5 million years ago following the tectonic movements of the Elbruz and Caucasus mountain ranges combined with the lowering of the sea level, the Aral Sea has played an important political, social, cultural and economic role for many ancient civilizations. Documented first by the Arab sources dating to the 7th century AD, the sea was the eastern political border of the Chinese empire under the Tang dynasty and a major economic resource for the Soviet Union. For thousands of years, people settled, lived are developed their tradition and culture along its shore.

 

An ecological and cultural disaster

Over its long history, the Aral Sea suffered from water level fluctuations. However, none of them is comparable with the almost complete shrinkage and the resulting ecological disaster that started during the 1960s. This relatively fast process had tragic consequences on the environment and on the wellbeing and health of plants, animals, and humans living in its proximity. The following pictures show the dramatic reduction of the sea from 1973 until today:

Aral sea shrinking between 1973 and 2020. 

But what caused this tremendous loss?

Until the second half of the 20^th century, the Aral Sea water level remained relatively stable thanks to two rivers, the Syr Dar’ya to the North and the Amu Dar’ya to the South, flowing into it. The deltas of these rivers sustained a rich ecological system and supported agriculture, animal husbandry, hunting, fishing, and the harvesting of reeds, used both as fodder and as a building material. Then, during the Soviet period, and especially from the 1960s onwards, both rivers were diverted to irrigate the desert, in an effort to cultivate cotton, melons, rice, and cereals. 

Indeed, irrigation has been credited as the main cause for the dramatic shrinking of the Aral Sea. While this practice was always used in the region, over-exploitation and a dramatic increase in irrigation during the Soviet Era led to an ecological disaster. The sea separated into two water bodies in 1987-1989, a ‘small’ one to the North and a ‘large’ one to the South. While the larger southern part of the Aral Sea is, by now, almost completely dry, efforts have been put underway to preserve the northern part, by building a dam to block the flow of water from the northern to the southern part, in order to conserve water levels stable.

The abandoned harbour in the city of Aral

The human-induced desiccation of the Aral Sea had tragic consequences on the ecosystem, with repercussions on both flora and fauna, humans included. Besides the damages to the sea, the entire zone surrounding it, with a population of several million people, was severely hit. The rising salinity of the water and the loss of inflow have hit hard the fishing industry, on which local communities relied heavily for their own sustenance. Navigation ceased in the 1980s. The rich ecosystems of the rivers’ deltas have suffered greatly too. Because of the decreasing level of the Aral Sea, desertification spread and intensified. In some places, salts have accumulated on the surface forming salt pans where virtually nothing grows. The increasing pollution, due to irrigation runoff containing salts, fertilizers, pesticides, herbicides, and cotton defoliants, has affected both flora and fauna, once thriving in the Aral Sea ecosystem. Indeed, prior to 1960, more than 70 species of mammals and 319 species of birds lived in the River deltas. Today, only 32 species of the formers and 160 of the latter remain.

Strong winds blow sand, dust, salt, and pesticide from the dried bottom of the Aral Sea to the surrounding lands, spreading pollution further. Both flora and fauna are affected by it. Plants die, or their growth is substantially reduced. Furthermore, airborne salt and dust have been considered to be a contributing factor in the increase of respiratory illnesses, eye problems, and throat and oesophageal cancer. Thus, the human population living in the ecological disaster zone of the Aral Sea has been equally affected by the water recession and widespread pollution. Another major issue was represented by the experiments on biological weapons conducted by the Soviet army between the 1950s and 1980s on a (formerly) small island in the middle of the sea, called Vozrozhdeniya (Resurrection) island. Besides the loss of the natural heritage of the region, the abandonment of villages and towns caused an irreversible loss of both the tangible and intangible cultural heritage. The enormous negative effect on this important piece of human’s history and heritage also attracted the attention of UNESCO which added historical documents concerning the Aral Sea to its Memory of the World Register as a resource to study the environmental tragedy.

Abandoned fishing boats along the dried shore of the Aral sea.

When in the later 1980s the Soviet government finally admitted the existence of a serious problem in the Aral Sea, an improvement program was launched, with the aim of improving the medical and health condition of people living near the sea and mitigating the negative effect on the environment. After the fall of the Soviet Union, the newly independent states of the region promoted initiatives to protect what remained of the Aral Sea and the population still living in its proximity. Cooperation with international organizations (such as the EU and the UN) and foreign governments (such as the US) was crucial for mitigating the effects of the ecological disaster and preserving the northern and western parts of the sea. Despite their efforts, the damages done to the environment and the Aral Sea could be irreversible, albeit their effects could be mitigated, and some parts of the sea could be preserved as they are. 

The Future of the Aral Sea

The restoration of the Aral Sea, albeit problematic and highly complex, is indeed possible. To do so, it would be necessary to increase as much as possible the inflow of both rivers into the Aral Sea basin, which implies that irrigation needs to stop or, at least, decrease drastically.

Of particular relevance would be the decrease of irrigation used for cotton cultivation, a plant that requires a huge amount of water. However, the current economic and political role that irrigation-based agriculture is playing in many countries will prevent governments to take strong and courageous decisions. Therefore, it seems that complete restoration of the Aral Sea to its former glory is nigh impossible. However, the possibility that the Aral Sea will completely dry up is equally very unlikely, as the Northern part of the former sea is relatively well-maintained, and the melting of snow would help in maintaining its level stable even if the northern river stopped flowing into it completely. Attempts to expand the current extension of the western part, as well as the central one, are still underway and today it appears very difficult for the sea to return to its original levels.

The Aral Sea should serve as a grim reminder of the potentially tragic consequences of ecological disasters caused by human activities and over-exploitation of natural resources. It also shows the interconnection between humans and nature, wherein the wellbeing of the latter influences dramatically the survival of the former. The history of the Aral sea represents a very clear example of the threat that unregulated agriculture, irrigation, and economic development and the damages that they can cause to both natural and cultural heritage, to the environment, and to humans themselves.