CLOUD SEEDING (Syllabus: GS Paper 3 – Env & Eco)

Context: Recently, the arid nation of the United Arab Emirates (UAE) experienced the "heaviest rain ever," resulting in flooding in Dubai, with the widespread rain believed to have been induced by "cloud seeding," among other factors.

Cloud Seeding

• About: It is a weather modification technique that improves a cloud’s ability to produce rain or snow by introducing tiny ice nuclei into certain types of subfreezing clouds.
• Cloud Seeding Methods

o Static Cloud Seeding: It involves the dispersion of a chemical, like silver iodide, into clouds. This substance acts as a crystal around which moisture can condense, enhancing the efficiency of rain clouds in releasing water.

o Dynamic Cloud Seeding: It focuses on amplifying vertical air currents, promoting increased water passage through clouds, resulting in more rainfall. This method employs up to 100 times more ice crystals compared to the static approach [source: Cotton].

o Hygroscopic Cloud Seeding: It utilizes salts dispersed through flares or explosives in the lower sections of clouds. These salts grow in size as they merge with water. 

• Process of Cloud Seeding: 

oWeather forecasters monitor atmospheric conditions and identify suitable clouds for seeding based on precipitation patterns. 

oThis technique can increase rainfall by up to 30-35 per cent in clear conditions and 10-15 per cent in more humid conditions.

• UAE's Pioneering Cloud Seeding Program: The UAE initiated its cloud seeding program in the late 1990s, making it one of the first Middle Eastern countries to use this technique.

Environmental Impact of Cloud Seeding

• Cloud seeding changes the expected rainfall distribution, potentially depriving neighboring ecosystems of precipitation originally destined for them.
• Introduction of seeding agents may disrupt natural processes like soil moisture levels, groundwater recharge, and river flows.
• Silver iodide, a common seeding agent, raises worries about silver toxicity, which could harm aquatic life and soil health if cloud seeding becomes widespread.