Why cloud seeding is not a solution to Delhi’s air crisis:

Context – Delhi Chief Minister Rekha Gupta has said that preparations have been completed to induce artificial rain through cloud seeding, marking a significant technological milestone in the capital’s fight against air pollution.

UPSC PYQ 2019

In the context of which of the following do some scientists suggest the use of cirrus cloud thinning technique and the injection of sulphate aerosol into stratosphere?
(a) Creating artificial rains in some regions.
(b) Reducing the frequency and intensity of tropical cyclone
(c) Reducing the adverse effects of solar wind on the Earth
(d) Reducing the global warming
Answer-(d)

What is Cloud seeding?

• It is a weather modification technique that improves a cloud’s ability to produce rain or snow by introducing tiny ice nuclei into certain clouds.
• Silver iodide, potassium iodide, dry ice (solid carbon dioxide), liquid propane or salts are injected into clouds. This is done with an aircraft, which injects the salts into the cloud.
• Injecting the particles makes clouds more capable of creating ice crystals, that gives rise to precipitation. Depending upon the temperature, these crystals fall as snow flake or melt to lead to rains.
• The amount of rains generated from cloud seeding depends on the number of ice nuclei inside the cloud and the amount of water available nearby to grow around it.
• These nuclei provide a base for snowflakes to form which then quickly grow and fall from the clouds back to the surface of the Earth.

What are its merits?

• It can bring artificial rains in water starved and drought prone areas like Rajasthan, Maharashtra, UAE, China etc.
• It can prevent crop failure, boost agricultural productivity and can support rural livelihoods.
• It can help fill dams and recharge groundwater → crucial for drinking water, irrigation, and hydropower generation.
• It can help in reducing air pollution as it helps wash out PM2.5/PM10 and other pollutants → China and UAE use this to clear smog.
• It can help in mitigating hazards; for e.g. used to reduce hail formation (by spreading water droplets more evenly) and to tackle forest fire.
• It can induce artificial snowfall in mountainous regions to maintain snowpack.

What are the issues involved?

• It can’t create new clouds.
• There is a week evidence that seeding reliably increases rainfall.
• Reduction of pollution is also for a very temporary period. The pollution levels go back up within a day or two.
• The long-term effects on agriculture, ecosystems, and human health remain poorly understood as repeated use of silver iodide can accumulate in soils and water bodies.
• If cloud seeding coincides with intense rainfall, it can lead to flooding, causing damage to infrastructure, crops, and livelihoods, or loss of life.
• Political disputes: If one state seeds clouds, neighbouring state may allege theft of their rainfall.
• Lack of accountability and responsibility – No clear legal or global environmental regulation framework.

Important Case Studies

Practice Question:

What is cloud seeding? How far do you agree that cloud seeding can help India to resolve its issues of air pollution and water scarcity? (10 Marks, 150 words)