With advancements in science and technology, weather modification to control the local environment has been made feasible globally. Cloud seeding is one of the weather modification approaches to tweak artificial rain.
This approach is feasible only in an atmosphere filled with pre-existing clouds. Global warming has intensified the scramble for water worldwide and has battered the different regions with heatwaves, wildfires, and other abiotic stresses like drought. Cloud seeding has emerged as a wonderful technology to help the snow Gods. When the moisture in the clouds after reaching some threshold level cannot be held for longer, it causes rain. Therefore cloud seeding is the process of altering the structure of clouds to enhance precipitation.
How is cloud seeding facilitated?
In the process of cloud seeding, the rain 'seeds' like silver iodide (AgI), potassium iodide, liquid propane, table salt, or solid CO2 (dry ice) are dumped onto the pre-existing clouds to tweak artificial rain. The seed dispersal is done either through special aircraft or artillery guns to yield rain shower. The silver iodide is an excellent seeding agent having a physical structure similar to natural ice crystals, and dumping dry ice into supercooled clouds can generate ice crystals. The seeding agents like silver iodide helps in lowering the cloud temperature to generate more ice crystals. Through liquid freezing, ice crystals grow and then fall to create snow. The cloud seeding efficacy relies on the prevailing weather conditions as some moisture or pre-existing clouds are a must for cloud seeding.
History of cloud seeding
During the 1940's Dr. VJ Schaefer, while studying cloud formation for General Electric, postulated the idea of cloud seeding. Subsequently. This process has been used frequently to promulgate precipitation, altering hurricanes, dissipate fog, and reducing lightning or hail. Cloud seeding has been used across countries, including India. China is a regular user of cloud seeding to induce rainfall during droughts.
Cloud seeding in military operations
During the Vietnam war (1967-1972), the operation' Popeye' was a military operation of the United States airforce for cloud seeding. It was a highly classified mission to modify the environment of specific locations in Vietnam's war zone area to extend the monsoon season and impede the military supply to Vietnamese soldiers. They used silver iodide as a seeding agent for this operation.
Why cloud seeding?
Cloud seeding is practiced for a variety of reasons globally. It is successfully utilized by Ski resorts to enhance snowfall.
The hydro-electric firms also exploit this approach to make more water supply available for the generation of electricity.
It is used to clear the weather by removing fog and also manage hail.
Cloud seeding is also employed to reduce the severity of air pollution.
To generate artificial rain during droughts.
How safe is it to mess with the environment?
Recently, China has announced its ambitious plan of expanding the weather modification program to cover an area bigger than India's size. The large scale weather modification will surely impact the neighbors. The seeding agent like silver iodide is considered toxic to aquatic life and hence harmful for our environment. We must look for an alternative, non-toxic seeding agents. Global cooperation is a must for the safeguard of the health of humans and the environment.
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