The State government of Karnataka has taken a proactive step to combat the persistent drought-like conditions afflicting the region. They plan to utilize cloud seeding operations, a process designed to stimulate and enhance rainfall, in the monsoon seasons of 2019 and 2020. The overarching goal is to maximize water capture during these essential rainy periods.
Understanding Cloud Seeding
Cloud seeding is a process wherein either dry ice or more commonly, silver iodide aerosols are dispersed into the upper portions of clouds. The purpose? To stimulate precipitation processes and encourage the formation of rain. Cloud seeding endeavors typically involve the use of planes to spray chemicals into clouds, causing smaller particles to condense into larger, rain-inducing droplets.
Various Methods of Cloud Seeding
There are three primary cloud seeding methods: hygroscopic, static and dynamic cloud seeding. Hygroscopic cloud seeding involves dispersing salts via flares or explosives into the lower sections of clouds. As water merges with these salts, they grow in size.
Static cloud seeding entails dispersing a chemical, often silver iodide, into clouds. This chemical provides a crystalline structure around which moisture can condense. Dynamic cloud seeding, on the other hand, seeks to elevate vertical air currents, encouraging an increased volume of water to pass through the clouds, thus resulting in higher rainfall.
Applications of Cloud Seeding
Cloud seeding serves a broad range of applications. It can be used in agriculture, to create rainfall and provide relief to regions grappling with drought. For instance, ‘Project Varshadhari’ was implemented in Karnataka in 2017 for this very purpose.
Furthermore, it has been used to increase power generation, particularly in hydroelectric projects. This application has been successfully tested over the past four decades in Tasmania, Australia.
In dealing with water pollution, cloud seeding can assist in maintaining minimum summer flows of rivers and mitigating the impact of treated wastewater discharges from industrial and municipal sources.
Other applications include fog dispersal, hail suppression, and cyclone modification – the principle behind the USA’s “Project Sky Water” originated in 1962. Moreover, it can be leveraged to combat air pollution by settling down toxic air pollutants through the rain, as contemplated recently by the Central Pollution Control Board for handling Delhi’s air pollution.
Even tourism can benefit from cloud seeding, by making typically dry regions more hospitable and thus attracting more visitors.
| Method | Uses | Examples |
|---|---|---|
| Hygroscopic cloud seeding | Augment rainfall in drought areas | ‘Project Varshadhari’ |
| Static cloud seeding | Increase power generation | Tasmania, Australia |
| Dynamic cloud seeding | Combat air pollution | Delhi’s air pollution reduction |
Challenges with Cloud Seeding
While cloud seeding offers a range of benefits, it is not without its challenges. Potential side-effects to animals, plants, people, and the broader environment are of concern, due to the chemicals used in the process. There are also fears that it might eventually lead to abnormal weather patterns or climate change. For instance, places that customarily receive moisture might start experiencing drought due to the artificial stimulation of rain.
The process is also expensive. Delivering chemicals to the sky and dispersing them into the air by flare shots or airplanes involves substantial costs and logistic preparations. Furthermore, as the artificially induced rain falls, seeding agents such as silver iodide, dry ice, or salt will also descend. This could contribute to pollution; residual silver discovered near cloud-seeding projects is considered toxic, while dry ice can contribute to global warming as it is essentially carbon dioxide.