Context

• The environmental disaster caused by the drying up of the Aral Sea has been described as a silent Chernobyl, research presented at the Second Central Asian Dust Conference (CADUC-2) that began in Nukus, Uzbekistan on April 15.

Key Points

• It is noteworthy that by the beginning of the 1960s, the world's fourth largest lake, the Aral Sea, dried up and later became synonymous with environmental disaster on the lines of the Chernobyl nuclear disaster.
• The above research states that the desert that emerged due to the drying up of the Aral Sea turned Central Asia into a dusty place.
• This dust is more dangerous than normal dust. This event is also likely to have a negative impact on the global climate. However, more study is needed to find out.
• According to this study by the Leibniz Institute for Tropospheric Research (TROPOS) and the Freie Universität Berlin, Central Asia has become 7 percent dustier in the last 30 years due to the drying of the Aral Sea. Between 1985 and 2015, dust emissions from growing deserts nearly doubled from 14 to 27 million tons.
• It says the amount of dust so far has probably been underestimated because two-thirds of the dust remains clouded in the sky and therefore is not noticed by conventional satellite observations.

Effect

• This dust not only endangers residents of the region, but also affects air quality in the capitals of Tajikistan and Turkmenistan.
• Moreover, it may accelerate the melting of glaciers and thus increase the water crisis in the region.
• This dust is much more dangerous than normal dust because it contains residues of fertilisers and pesticides from former agriculture.
• Impact on climate: Notably, the TROPOS and FU Berlin team of researchers used the atmospheric dust model COSMO-MUSCAT to estimate the impacts of dust from the Aralkum Desert, which simulates emissions, concentration in the atmosphere and radiative effects of dust particles.
• They found that while agricultural areas on the Syr Darya are negatively affected by dust, it can also be felt in large cities in Central Asia such as Ashgabat (capital of Turkmenistan) and Dushanbe (capital of Tajikistan) more than 800 kilometers away. Could.
• Dust on the ground cools during the day as it reflects sunlight, and warms at night as it re-radiates heat from the ground. The net radiative effect of dust can therefore be cooling or warming, depending on the amount of dust in the atmosphere, time of day, season, surface albedo, and the precise mineralogical and optical properties of the dust.
• Looking at changes between past and present, the approximately doubling of dust emissions in the Aral Sea/Aralkum region has led to an increase in both radiative cooling and radiative heating at the surface and atmosphere.
• Researchers have also found evidence that dust can change entire weather patterns.
• This increases the ground air pressure in the Aral region by +0.76 pascal on a monthly time scale. This means an intensification of the Siberian high in winter and a weakening of the warm Central Asian low in summer.

Reason for drying of Aral Sea

• The Aral Sea was fed by two great rivers of Central Asia – the Amu Darya (Oxus in ancient times) and the Syr Darya (Jaxartes) – which flowed from the Pamir and Tien Shan mountain ranges of High Asia, respectively.
• Due to excessive use of rivers for agricultural irrigation, less water enters the lake. As a result, vast areas dried up, the lake shrank to a fraction and vast areas became desert.
• The area of the Aralkam Desert, formed in place of the Aral Sea, is 60,000 square kilometers. While significantly smaller than the neighbouring natural deserts of Karakum (350,000 square kilometres) in the south of Turkmenistan and Kyzylkum (300,000 square kilometres) in the south-east of Uzbekistan and Kazakhstan.
• Yet Aralkum is one of the most significant man-made dust sources on Earth.

Important Facts For Exam

Aral Sea

• Countries bordering the Aral Sea: Uzbekistan and Kazakhstan