The erratic rainfall in some parts of India, especially less than expected performance of southwest monsoon in southern states like Andhra Pradesh and Karnataka has forced the state governments to explore the option of cloud seeding, an artificial method to induce rain over parched fields and to restore the water levels in reservoirs. While Andhra Pradesh government is using the airplanes to seed the cloud, Karnataka government has opted for ground based cloud seeding technology, using small rockets.
The technology of using 'rain rockets', in which small rockets carrying finely ground sodium chloride (common salt) are launched from the ground to induce precipitation of clouds. The minister claims that this will be cheaper and different from the expensive cloud seeding technology of using airplanes. These mini rockets would be launched form temporary towers erected specially for this purpose or from skyscrapers. However, for launching of this mini rockets the weather conditions should be favorable.
With rising concerns about global warming and climate change, some Indian scientists are advocating for adoption of cloud seeding technology to mitigate these problems and address the issue of recurring drought. This technology has been used in 40 countries and China claims to produce an additional annual rainfall of 60 billion cubic meters through cloud seeding.
How effective is the cloud seeding technology? In early eighties the Karnataka government used this method to bring rain to drought-affected areas. It had little impact, and the results were controversial. Still, it was extensively used in Andhra Pradesh and Maharashtra to mitigate drought. Kapil Sibal, as minister for science and technology in the previous government, had informed the Parliament that the effectiveness of the cloud seeding experiment in Maharashtra during 2003-04 could not be ascertained and that the central government had no plans to develop cloud seeding as an effective technology to address drought.
The physical processes of each cloud's life cycle are different and provide very narrow window of opportunity for intervention via cloud seeding, which makes it difficult to predict when and where the effect of seeding will occur.
The cloud seeding experiments in USA during 1950s clearly indicated that it had very marginal impact but it could lead to harmful effects on weather modification.
The doubts about the time and place of cloud seeding still persist. The physical processes of each cloud's life cycle are different and provide very narrow window of opportunity for intervention via cloud seeding, which makes it difficult to predict when and where the effect of seeding will occur.
As forestry science evolved on the experience of temperate forest in Germany proved to be inadequate and disastrous when applied to the tropical forests in India. Similarly the cloud seeding experiments carried on in USA and Europe are done for orographic clouds that are structurally different from the tropical cumulus clouds, which are warmer. Despite this basic structural difference of clouds many states in India have actively sought the assistance of cloud seeding to resolve the natural phenomenon of receiving the precipitation.
American Meteorological Society has categorically stated that "the use of untested weather modification techniques during severe droughts, as a means of increasing precipitation, is not recommended. Opportunities to increase precipitation are typically minimal during droughts and only well-tested techniques should be considered, realizing that only limited precipitation augmentation will probably result".
There is concern among scientists about the clouds seeding technology resulting in long-term adverse impact on the environment as well on the people. Will the government pay the costs of this adverse impact to people and property or damage to the natural resources?
Current knowledge about cloud seeding indicates that it might have very marginal impact on the total precipitation, leading to an increase of ten percent of rainfall. With such limited possible impact, are our politicians and bureaucrats taking a rational decision?
There is concern among scientists about the clouds seeding technology resulting in long-term adverse impact on the environment as well on the people. Will the government pay the costs of this adverse impact to people and property or damage to the natural resources? In the wake of Bhopal accident, there is need to address these ethical and legal problems before going ahead with cloud seeding.
It is strange that the natural phenomenon of cloud formation and rainfall is being treated as a stage to wage the war on nature. Rockets and airplanes are being used to target the clouds as if nature can be forced to yield through precipitation. The belief that technology can solve all the natural problems needs to be taken with a pinch of salt.
The companies who are engaged in cloud seeding are basically commercial companies who want to earn handsome profits. In order to sell the untested cloud seeding technology they would use all available means to back their claims of producing results. The mini rocket technology is still in primacy stage and yet to develop into a time tested method in India. The state of Karnataka is willing to become the testing ground for this new technology. To embark on rain making without adequate certainty of positive results is nothing but putting taxpayers' money at stake by our political establishment.
Should we allow these private profit motives to get priority over well-tested methods of drought proofing?