Concern about access to water and water availability is not a recent issue, there are records of aqueducts (pipes to take water to distant locations) for almost 2,000 years and some of them more than hundreds of kilometers apart, dating back to the time of the Roman Empire. Its importance was such that it was a fundamental part of expanding empires, maintaining populations and enabling agriculture and animal husbandry.
Today, the monumental aqueducts have been transformed into kilometers of distribution networks, water reservoirs, pumping and water treatment stations to guarantee universal access to water. But water is not always available at the home tap, either due to the lack of a nearby water source or the large demand required such as irrigating crops, containing fires, recharging groundwater levels or large hydroelectric dams.
Several places around the world do not have abundant water availability and yet are home to thousands of people, such as locations in the United States, Mexico, United Arab Emirates, Russia, South Africa and even Brazil. And it is no coincidence that these places need to adopt water supply measures such as water desalination plants or underground wells. But both alternatives are expensive and groundwater levels drop year after year.
Thinking about alternatives to water scarcity in these places, scientists raised the possibility of artificially producing rain. However, the technique depends on minimum prerequisites such as the presence of rain clouds.
The “cloud seeding” technique involves the use of chemicals, such as silver iodide and dry ice (solid carbon dioxide), to stimulate the formation of rain. Using aircraft and drones, these products are launched into the clouds with the aim of increasing the water supply in dry areas. The process aims to increase the volume of rain that would fall naturally.
The process is based on understanding the states of water. Raindrops do not form spontaneously; vapor in the atmosphere needs particles (condensation nuclei) to condense. Silver iodide, for example, has a similar geometry to rainwater and acts as fragments to which moisture can cling, resulting in the coalescence of clouds and, consequently, precipitation.
So it is not correct to say that it is possible to create rain artificially, but that there is a way to encourage the water to go from a gaseous state to a liquid, in the form of rain and to precipitate over the place where the clouds are. In addition to combating widespread drought, the technique can be an alternative for fighting forest fires, recovering degraded or burned areas and even raising the level of dams used for human supply or electricity generation.
But not everything is rosy, some scientists question the ability to actually sow rain artificially, the question that remains is how much rain would be precipitated naturally without the stimulus of particles added to the clouds, although some places like the United Arab Emirates have already achieved good results with the artificial rain method.
The technique can be a good ally to promote an increase in precipitation in places where there are favorable conditions and the formation of clouds with sufficient humidity, but this cannot be seen as the solution to droughts and lack of rain in several locations. Scientists increasingly associate dry periods and lack of rain with climate change and human influence on the climate.
References:
https://www.nexojornal.com.br/expresso/2024/04/18/chuva-em-dubai-artificial-como-funciona