Droughts in the Anthropocene

Aral Sea – Conserving and rehabilitating a lost sea

The Aral Sea, once one of the largest lakes in the world, lies dry barring a few small surviving oases of water. Significant desertification in the region has led to the emergence of a new desert, the Aralkum [1]. Located between Kazakhstan and Uzbekistan, it was once a vast expanse of water, supporting rich biodiversity and ecosystems that underpinned a bustling economy [2]. The Aral Sea’s basin is spread across seven countries in Central Asia that feed the Syr Darya and Amu Darya rivers, which replenished the lake’s water lost by evaporation. The diversion of large quantities of water from the Syr Darya and Amu Darya rivers in the 1960s to turn arid land into irrigated cotton crops in Kazakhstan, Turkmenistan and Uzbekistan tipped the balance. The loss of inflows into the terminal lake led to a rapid drying of the Aral Sea and a catastrophic decline of the ecosystems and societies it supported. The once abundant fisheries had all but collapsed by the 1980s, as salinity levels rose to toxic levels [3] and wet land habitats shrunk by 95% [4]. The rapid drying of the Aral Sea was compounded by two decades of drought that furthered the imbalance between water inflow and evaporation loss. The Aral Sea split into two parts in the late 1980s, the Small Aral Sea and the Large Aral Sea, as it continued to dry. By 2006, the lake’s water level had fallen 23 metres, reducing its surface area by 74 per cent and its volume by 90 per cent [5]. The loss of water has seen salinity levels rise around twelve-fold since 1957 [6], making it toxic to many species it once supported. The lake also played an essential role in the area, as it had an influence on weather and water regimes that supported the ecosystems and societies that surrounded it. The decrease in water affected the replenishment of groundwater, causing the surrounding landscape and ecosystems to dry out, furthering pressures on livelihoods as

the land became increasingly saline and harsh and reducing productivity. The continued drying out of the local region combined with increasing temperatures driven by climate change has created large dust storms. These whip up salts and toxic chemicals such as pesticides and fertilizers deriving from cotton farms upstream, causing health issues in the surrounding areas and concerns around the degradation of soil and land productivity [2]. The Aral Sea catastrophe provides evidence of how human water interventions can create droughts that significantly impact both the environment and societies. Improving the health of the Aral Sea is a complex undertaking, as it stretches across various countries, and transboundary management of water needs to be coordinated more effectively to provide maximum benefits both environmentally and economically across all countries. Capacity- building of water management organizations, improvement of education in the water sector and environmental conservation will be vitally important to improve monitoring, information- sharing, water budgeting and modernization of water infrastructure. The rehabilitation of the Aral Sea itself is very unlikely. However, improving the maintenance and securing the water supply of remnant and newly created deltaic ecosystems can facilitate the partial recovery of the social, economic and ecological systems it once supported. Conserving the remaining parts of the sea is essential to sustain livelihoods and to maintain the surviving biodiversity and capture fisheries. Supported by the Central Asian Governments, the International Fund for Saving the Aral Sea (IFAS) is one organization working on solving the complex issues of the Aral Sea basin. Kazakhstan has also implemented a project to conserve the

Aral Sea: the construction of the Kok-Aral Dam. The Dam separated the two parts of the Aral Sea by preventing flow from the North (‘the Small Sea’) into the lower-elevation South Aral (‘the Large Sea’) and has helped to restore the delta and revive fisheries and the wetland ecosystem [7]. Several other dams have been proposed to support the remaining parts of the Aral Sea. In 2018, the Republic of Uzbekistan committed to upgrading almost 30 per cent of its irrigated area to modern water-saving technologies over five years [8]. This initiative has the potential to improve water supply to the Aral Sea. The country has also nearly completed the targeted planting of 500,000 hectares of forests on the bottom of the Aral Sea to combat desertification and reduce salt dust storms that impact health and agricultural productivity [8]. The provision of water is critical to improve the water balance and replenish the Aral Sea, but it may also help insure against the prolonged pressures of droughts and climate change. The projected temperature rise may negatively alter the water balance through higher rates of evaporation. These uncertainties should be built into strategies to conserve the Aral Sea.

ASIA AND THE PACIFIC

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