The concept of artificial rain as a way to combat severe air pollution has been making waves recently. New Delhi has struggled with rising levels of air pollution for the past decade, with the recent Air Quality Index measurements being consistently over 450, signifying worsening air quality. These high levels of air pollution have now begun to bring a normal, day-to-day life to a standstill. Headlines about flights being grounded or prevented from taking off in the country’s capital due to poor visibility caused by pollution have now become commonplace. In such a dire scenario, the only way forward is to think outside the box and come up with solutions that not only provide immediate relief in the short term, but also act as a sustainable long-term solution. One such idea that was proposed to tackle the ever-growing problem of air pollution was that of artificial rain.
Artificial rain, or cloud seeding is a method by which one can modify the weather and bring about precipitation. This is done by introducing a variety of substances to clouds in an attempt to induce rainfall. Clouds are made up of condensation particles called ice nuclei. These particles are the ones responsible for precipitation and are essentially ice crystals that are formed when water vapor condenses around dust particles present in the atmosphere. Cloud seeding modifies weather conditions by introducing ice nuclei into “subfreezing clouds”. These ice nuclei then act as a base for snowflakes to form, melt and then subsequently precipitate. Cloud seeding speeds up this process and causes the snowflakes to grow at a quicker rate, and consequently fall from the clouds in the form of rain drops.
While cloud seeding to produce artificial rain has been gaining traction recently as a potential solution to the various problems of climate change, this idea has been around for over 60 years. The concept first originated in the 1940s in the state of New York by Vincent J Schaefer, Bernard Vonnegut, and Irving Langmuir. They studied the size, formation, production and behavior of particles in the atmosphere and found evidence to support their theory on seeding particles into clouds to induce rainfall. They created a man-made cloud in a laboratory freezer and seeded it using dry ice to produce snow. Further research revealed that silver iodide can be used as an effective seeding agent. This discovery shifted the way in which cloud seeding would be used in the future.
Cloud seeding is usually performed via ground-based generators or by aircrafts. Most cloud seeding arrangements use silver iodide to help in the creation and production of ice crystals. According to Desert Research Institute (DRI), cloud seeding operations tend to be performed in the winter months when storm cloud systems pass through the designated project areas. In the event that these storm systems fail to pass through the project area during the winter months, performing cloud seeding becomes impossible due to the lack of moisture-laden clouds in the atmosphere.
Cloud seeding has been successfully applied in countries like the United Arab Emirates and the United States of America. There are quite a few benefits of using cloud seeding. Not only does this method of artificial rain help in improving snow cover and increasing rainfall, but it also supplements the natural water reserves of the local communities in the designated project areas. In the American state of Nevada, cloud seeding techniques were proven to be effective in aiding the enhancement of snowpack in the mountains by over 10% every year. Thailand used cloud seeding operations to suppress wildfires and reduce heat waves. The UAE uses cloud seeding primarily to expand the scope and capacity of its agricultural activity. Countries like Australia, China and USA primarily use cloud seeding to mitigate droughts. They do this by creating artificial rain and subsequently maximizing the utilization of this rainwater.
In India, there have been calls to implement a similar system of artificial rain to combat air pollution in New Delhi. Our capital city is famously known to have the worst AQI in the entire country despite the city government taking measures to reduce pollution like the odd-even vehicle scheme and bans on certain petrol and diesel operated three and four wheelers. Worsening air quality levels have urged government under Gopal Rai (New Delhi Environment Minister), to appeal to the central government to intervene with cloud seeding in an attempt to reduce air pollution in the city. A thick layer of smog has taken residence in Delhi’s atmosphere and is proving to be a cause of concern because it doesn’t seem to be going away anytime soon. Rai appealed to Prime Minister Modi to step in and offer help. He stated that if the center has concerns with the implementation of artificial rain systems, then they are morally obligated to provide alternate solutions to tackle the smog problem. New Delhi administration plans to use cloud seeding and artificial rain to “wash away” pollutants and to help dust and other particulate matter settle down.
While cloud seeding has been used to do a lot of good, the prolonged use of such weather modifying techniques cannot be overlooked. Apart from climatic consequences, questions about the ethicality of using such techniques have also been widely debated. For instance, weather modifying tools have been used as military tools. The use of Cloud seeding in the Vietnam war led to flooding, resulting in a prolonged monsoon. This historical event led to the signing of international treaties in the late 1970s. Further, ecological experts have raised doubts about the effectiveness of cloud seeding as a sustainable tool for change in the context of climate change. They claim that the negative effect or the cost of cloud seeding on the local system seems to be greater than the perceived benefits of implementing such a system. Seeing as cloud seeding can only be performed on certain types of clouds, the application of this techniques on a grander scale, one that takes into account major climate events, seems dubious and uncertain. Further, some experts claim that while artificial rain can positively affect the health of soil and water systems in the short term, prolonged use of cloud seeding may make local biosphere elements more susceptible to erosion and flooding.
Another concern raised is about the use of silver iodide as a catalyst in the cloud seeding process, specifically in places where cloud seeding has been brought up as a potential solution to air pollution. some experts are of the opinion that injecting more particulate matter into the sky, albeit to bring about positive results, may be doing more harm than good, as they believe that while silver iodide might not necessarily directly contribute to air pollution, increasing the concentration of particulate matter in the atmosphere may trigger other pollutants. Concerns about contamination have also been brought into the limelight, elucidating that the possibility of the inclusion of unknown particles in the process of cloud seeding can have disastrous implications.
Cloud seeding operations and artificial rain systems have been successfully used in several cities across the world. While the merit of such techniques cannot be denied, it is of just as much importance that we refrain from turning a blind eye to the negative connotations of using such weather modifying techniques. What is clear however, is that this is a field that requires a great deal of research and testing before it can be rolled out on a larger, maybe even commercial scale. Cloud seeding was devised as a way to help the environment by providing an innovative solution for drought prone areas and as a detoxifying mechanism in areas of severe pollution.
However, it is perfectly possible that this technique will create bigger problems than the ones it seeks to solve.
There is always a risk when one attempts to alter or tamper with the forces of nature. However, years of relentless use and indiscriminate exploitation of all of nature’s resources has led us to a stage where letting nature take its own course to heal and replenish its reserves seems to be nothing short of wishful thinking. The situation that mankind has created for itself is dire and will require carefully controlled and planned intervention with nature’s forces so as to bring back natural equilibria wherein different biospheres may thrive.
Written by Nandini Pillai
Edited by Shruti Shiraguppi
