“While this is a good initiative, when we conduct experiments in a lab, we can control most factors. However, when we take this to the real world, conditions are not always ideal,” said Manju Mohan, an atmospheric scientist at the Indian Institute of Technology-Delhi (IIT).
At the press conference announcing the launch of the mission M. Ravichandran, secretary, Ministry of Earth Sciences, gave the example of how rain often mars Independence Day celebrations, which falls during the peak monsoon season. “During an important event like Independence Day, we can push the clouds to avoid rain over Delhi,” he said.
Adding, “We want to go for initial experimental artificial rain suppression and enhancement. Lab simulations (cloud chambers) will be done in the next 18 months, but we’ll definitely go for artificial weather modification in the five-year time scale.”
Suppression and enhancement, in this context, likely refer to mitigation of rainfall through seeding, which can be theoretically used to advance rainfall or push it to a later time. But outside a lab, that’s easier said than done. “Clouds are very complex. Atmospheric factors like humidity, etc. play a major role in ensuring the success of such a project,” said Mohan.
Also Read: Population density, land scarcity: CEEW lists roadblocks to India realising its renewable energy goals
Cloud experiment lab
The IMD will soon be setting up a first-of-its-kind cloud experiment laboratory at the Indian Institute of Tropical Meteorology, Pune, which will help the agency study and analyse clouds and, by extension, modify weather systems. The lab will eventually help scientists “modify” weather systems to “suppress and expand” rain, hail, thunderstorms and even fog.
“The lab will be like a simulation to understand the dynamics and processes of a cloud. We will be setting up the lab in Pune over the next 18 months. So, by March 2026, we will have the lab,” said Ravichandran.
The tender for building the lab will be floated, where private and government labs will be called to build various equipment and machines required to analyse different aspects of a cloud. Once the machines are built, the simulation lab will be integrated.
Currently, the efficacy of cloud seeding in increasing rainfall in a region is only about 10-15 percent, according to studies.
Such experiments will, however, not be “on-demand” services that can start and stop weather systems on command, at least with the current available technology.
Utility of cloud seeding
On some days, knowing the weather for the day is top priority.
The Indian Independence Day, which is celebrated on 15 August—peak Monsoon season in northwest and central India—is one of the busiest periods for the Met Department. Senior officials from the department said that the science of studying the clouds will help seed or disperse them.
Cloud seeding is a weather modification technique that increases the amount of rain or snow that falls from clouds.
Rain is formed when water condenses around an aerosol particle (a “seed”), falling to earth as it becomes heavy.
This has been observed to happen with both naturally occurring particles, as well as anthropogenic emissions, explained Dr Thara Prabhakaran, project director of Cloud Aerosol Interaction and Precipitation Enhancement Experiment (CAIPEEX) at the Ministry of Earth Sciences. “Ship trails have been known to seed clouds and cause rain because the sulphates and sulphur particles ships emit are hygroscopic and attract water,” she said.
When a cloud starts to get saturated, this can be simulated by simply spraying particles into the clouds and forcing it to release water in the form of rain. For instance, cloud seeding can be used to cause rains in an area which is experiencing long periods of drought. However, this will only work if the area or any nearby area has conducive conditions, like active clouds, which can be pushed to cause the required rainfall.
Similarly, if a city is experiencing prolonged rainfall and flooding, active clouds can also be pushed away from the region.
“All this can be done if we study the cloud. Once we know exactly how the process works, we can tweak the cloud to cater to certain requirements,” Ravichandran said.
Scientists further explained that once the lab in Pune is up and running, in the next five years—by around 2031—Met Department will be able to conduct experiments to artificially suppress or enhance not only rainfall but also hail, thunderstorms, fog and lightning.
They will also be able to play around with altering the drop size distribution, suppressing ice crystals, coagulating droplets, etc.
Modifications of such parameters including raindrop size and ice crystal distribution becomes important depending on the area of rain, such as for agricultural crops.
Each aspect influencing the formation and precipitation patterns of clouds will be studied by altering temperature and moisture levels, and seeding will be done in different conditions to assess varying results.
Prabhakaran stated that projects like CAIPEEX, and now ‘Mission Mausam’, are excellent opportunities to understand cloud dynamics better, and thus eventually help modify extremely localised weather in a small area. “There is a large lack of data currently, and we are presently building up data for various experiments around the phenomenon of cloud seeding. Over the next two years, we will be building cloud chambers, such as those that exist in countries like USA, UK, Germany, and South Korea, to perform experiments.”
Today, the atmospheric scientists who make up India’s CAIPEEX experiment for the past decade, continue to do controlled small-scale seeding experiments and publish their results. Soon, Prabhakaran says, ‘Mission Mausam’ and other such projects aspire to also have airborne vehicles like planes that can help disperse aerosols with affinity for water for seeding, and also to document changes in clouds and rain.
Reliability & limitation
While cloud seeding and weather modification are being marketed as the “next big thing” to circumvent increasing impacts of climate change and extreme weather events, MoES scientists admit to the technique’s limitation—the fact that it won’t be an “on-demand” service.
Many conditions from the formation of the cloud itself to humidity levels will have to be considered before it is initiated. IMD’s experiments may not be effective in such a scenario. Even its own weather scientists acknowledge this.
Cloud seeding and modification can only be conducted if there is a presence of cloud over or around the affected area, said Ravichandran. “I cannot cause rainfall when there is no cloud. In the months when the pollution levels are high in Delhi and surrounding areas, cloud formation is uncommon,” he said.
Rain clouds are often low lying and tall, produced by warm air rising up from the surface. Heavy smoke and pollution prevents this convective process working effectively, hampering the formation of rain clouds.
Research studies and experts have also highlighted the limitations and concerns over weather modification in the long run. For instance, injecting silver iodide into the clouds is a standard method to seed the cloud. However, the impacts of introducing these particles into the atmosphere could, in turn, trigger the formation of other pollutants.
Mohan also highlighted that the unpredictability of weather systems is also increasing with climate change and a rise in extreme weather events. In such a scenario, there is a risk of technology becoming quickly outdated.
“Weather is becoming increasingly unpredictable and the vulnerability is also increasing. This means that we might not be able to use old technology to attain the same results. We will have to constantly upgrade our technology to keep up,” she said.
It’s been done in China, Russia, UAE
While cloud seeding and the artificial modification of weather systems might seem like a futuristic idea in India, several countries around the world have already attained some level of expertise in the area.
In 2019, the Chinese Meteorological Department relied on cloud seeding to “artificially alter the weather, causing rain to fall to meet the needs of the population and economy”. China has since developed a local cloud seeding plan for each city, which is being implemented with a coordinated team of researchers, civic agencies, and defence resources.
The primary reason for carrying out this exercise is the country’s unequal distribution of water resources. According to one report, China carried out seeding between June and November 2022, where 241 planes and 15,000 rockets were used to cause 8.56 billion metric tonnes of additional rainfall in the Yangtze River basin. The country has taken its ambitions much further than others, with their planned Sky River project working to divert rain to an extra 1.6 million sq km in the dry Tibetan mountains some time in the future.
The UAE has been experimenting with cloud seeding and weather modification techniques since 1990. Being an arid and water-parched terrain, the idea behind the experiments was to enhance rainfall and reduce water shortage. In the 2000s, the Emirati government also sanctioned 20 million USD for research on cloud seeding.
Russia and Thailand too have used this technique to suppress heat waves and wildfires.
(Edited by Amrtansh Arora)
Also Read: Gujarat flooded, eastern India parched & no ‘monsoon breaks’. IMD predictions hit the mark