Cloud Seeding: Clouds with A Silver Lining

Farmers’ suicides, droughts, urban water crunches. Erratic monsoons have cast a long history of suffering on India through the ages. Coupled with inadequate irrigation systems, they leave the large agricultural sector perpetually looking skywards.

It’s time to say goodbye to ancient rain dance rituals. The geeks in the labs want to create rainfall, and not just invoke it. Cloud seeding or weather modification is the new kid on the block, welcomed by some and regarded cynically by others.

Cloud seeding is an advanced scientific method which aims to artificially create rainfall by inducing precipitation in clouds. This is done by releasing substances into the atmosphere that serve as nuclei around which the clouds can condense. Generally silver iodide is used for cold clouds, and hygroscopic materials such as salts for warm clouds. These can be introduced into the air by aircrafts or rockets fired from the ground.

Although the technology has been explored in the West since the 1960s, cloud seeding emerged in India very recently when the Karnataka government began using it successfully in 2003-2004. China shot to the environmental wall of fame when it claimed to have used it to prevent rains from disrupting the Beijing Olympics in 2008. The Chinese government reputedly spends 80$-90$ million a year on cloud seeding.

The apparent success of the Chinese experiment has led to an explosion of this technology in India and other parts of the world. The Andhra Pradesh government has put a new cloud seeding project in place this year, the tender for which was given to Hyderabad-based company Agni Aviation. It aims to target 12 districts which fall under the rain shadow regions of the state. The cost of conducting the aerial experiments is approximately Rs.25 crores. Sounds steep, but building dams and irrigation canals is arguably more expensive and time consuming.

The Brihan Mumbai Municipal Corporation jumped on the bandwagon in August and engaged the same aviation company to undertake similar efforts, which have had unsatisfactory results so far. Mumbai’s daily water requirement is 4,100 litres, but it receives only 3,400 litres from its reservoirs and lakes.

Unfavourable cloud formation was the reason cited for the failure of the experiment in Mumbai. This is where the silver lining gets eclipsed – there are no precise methods yet to measure the effectiveness of a cloud seeding experiment. Proponents of the technology say that it can increase rainfall by 30-40%, but this is dependent on many changeable variables like cloud composition and temperature. Moreover, even if it rains, there is always room to wonder whether the same might have happened without human intervention and costly labour.
There are also deeper problems to be addressed – such as the possibility of cloud seeding in one area causing clouds to be diverted from their original course and depriving other areas of moisture. There have allegedly been feuds between neighbouring regions in China because of this literal ‘’side effect’’.
Nevertheless, weather modification remains an attractive bandaid for watery woes as well as an inviting territory for more research. These techniques have been used for various other purposes such as reducing fog levels around airports in the U.S. This idea is not yet on Indian scientists’ priority lists, but it could well become popular soon. The inconveniences surrounding air traffic control in northern states like Delhi in winters is calling out for radical scientific solutions.

With state governments pumping money into this field, there are prospects of cloud seeding becoming a permanent aid for the agricultural economy. Let’s hope it showers some good fortune upon our parched lands.

Kruttika Nadig

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