Water Security Risk – Part Three
Amirhossein Khodaei – Researcher
The Astonishing Transformation of Weather Modification: From Dream to Reality
Have you ever wondered what the world would look like if humans could, with the push of a button, make rain fall wherever they wanted? Perhaps this idea sounds more like science fiction than science, but the truth is that humanity has been trying to do exactly this for decades, sometimes with limited success and sometimes with controversial results. Today, more than fifty countries around the world are involved in this technology in one way or another, and the frontiers of knowledge in this field are expanding every day. However, what has transformed this field unprecedentedly in recent years is the entry of artificial intelligence and advanced technologies, a development that is turning cloud seeding from an experience-based art into a precise, data-driven science. This eventful journey, from early experiments to large-scale national projects, is a fascinating story that we will explore below.
Classical Methods: Cloud Seeding
The simplest and best-known method of weather modification is called cloud seeding, which has existed since the 1940s. In this method, substances such as silver iodide or dry ice (frozen carbon dioxide) are injected into cold clouds (below zero degrees Celsius) using aircraft, drones, rockets, or special cannons to create artificial ice crystals and induce rain or snow. Silver iodide has a crystalline structure similar to ice and, without the need to cool the environment, causes supercooled cloud droplets to freeze.
For warm clouds (above zero degrees Celsius), substances such as table salt (sodium chloride), potassium chloride, calcium chloride, or urea are used. By absorbing moisture, these substances create larger droplets and accelerate rainfall. Methods for dispersing these materials include ground-based generators, airborne flares, and rockets carrying the seeding materials.
It should be noted that increasing rainfall is different from making rain. Cloud seeding is effective only when rain-capable clouds already exist. In other words, its role is like adding salt to food, not creating the food from nothing. Scientific evidence indicates that, at best, this method can increase precipitation by around 1 to 10 percent, and its effectiveness depends heavily on weather conditions and cloud type. The World Meteorological Organization (WMO, 2020) has also emphasized in its report that cloud seeding can be effective under specific conditions and with strict adherence to protocols.
Fog Dispersal
Another operational application of cloud seeding is the removal of fog at airports and on highways. In supercooled fog, artificial ice crystals are created using silver iodide or dry ice, causing the tiny fog droplets to be consumed and visibility to improve. This method is used at many airports around the world and is considered one of the most successful applications of cloud engineering.
Hail Reduction
By injecting seeding materials into hail-producing clouds, the number of ice nuclei is increased. This causes a larger number of smaller hailstones to form, which melt before reaching the ground. This method is widely used in countries such as China, the United States, and Russia, and experience in North Dakota has shown that seeding was effective in reducing hail in approximately 20.8 percent of cases.
The Artificial Intelligence Revolution in Weather Modification
Perhaps the most important development of the past decade in cloud engineering has been the introduction of artificial intelligence into this field. AI is no longer merely an auxiliary tool; it is becoming the brain behind cloud-seeding operations. But exactly what does AI do?
