Wednesday, December 8

In search of an à la carte climate to alleviate the drought


China wants sow clouds in more than half of their territory by the year 2025 and in the United Arab Emirates they have spent months trying to make it rain in the desert. It is not a futuristic utopia. The World Meteorological Organization (OMM) has endorsed the effectiveness of several methods to increase rainfall, but the proliferation of conspiracy theories and deceptive deals on the internet they have overshadowed scientific advancement.

At least in Europe, where there are already luxury companies like Oliver’s Travel that in exchange for 150,000 euros they ensure rain-free weddings for healthy pockets. In Spain, without going any further, there have been towns that have come to demonstrate for the suspicion that a legion of planes were stealing their clouds and with them, its storms. “The world of atmospheric modification is full of scammers and misinformation,” says José Luis Sánchez, professor of Applied Physics and climate researcher. But, is it really the human being capable of solving the problems of drought through the creation of artificial rain? What about propaganda and what about reality in the ambitious plan of the Chinese government? How do you plant a cloud?

The ability of man to create rain was something reserved for science fiction novels or mythology until in 1946, the Nobel Prize Irving Langmiur sprinkled dry ice on a cloud. The American chemist managed to make it rain, but the water generated by condensation evaporated before reaching the ground. He failed, but left the forecast that in the future “it would be easier to change the climate to our liking, than to predict its capricious changes or twists.”

Years after his death, it was shown that instead of injecting dry ice on the cloud mass it was more effective to do it with silver iodideOf course, for the process to culminate in precipitation, a very specific type of cloud had to be acted upon. ‘Cold’ clouds, less than 0 degrees Celsius, which are usually embedded between mountain peaks and are called orographic clouds. José Luis Sánchez, who has participated in several investigations aimed at knowing the potential of clouds and their behavior, explains that the methods for creating artificial rain are based on a very simple maxim: «The drop, so that it leaves the cloud and becomes in rain has to exceed 150 microns in size. All the processes are aimed at the droplets growing, because as their size increases, their internal bonds weaken and they are more likely to mix with each other and end up falling to the ground. Small droplets are impenetrable, like billiard balls. ‘

Each cloud has “tons of water in it”. But if a cloud mass gives rise to rain, it never precipitates more than 10 percent of the total water it houses. “This great water potential is what has prompted us to investigate whether the precipitation processes can be accelerated so that instead of the cloud discharging 5 percent of the water it contains, the percentage rises to 5.5. A small amount and that may be less, but that would be part of the solution in areas that suffer intense periods of drought», Says this expert.

Silver iodide or hygroscopic salts are dispersed in the clouds by means of airplanes or generators that send the chemical compound from the ground
Silver iodide or hygroscopic salts are dispersed in the clouds by means of airplanes or generators that send the chemical compound from the groundABC

The World Meteorological Organization collects in several reports how the cloud seeding process occurs through the injection of silver iodide and in them emphasizes that it is a method in which “The negative effects of pollution are totally ruled out”. An argument that a certain sector of environmentalism usually uses without any scientific basis. «It is curious that in places like Australia have been the greens who have promoted cloud seeding in natural parks and ecosystems that, due to climate change, they were having problems because it was snowing less and less. In California, for example, have increased snow for more than 40 years to help fill the reservoirs, because the state’s water is concentrated in the north.

Cheap and ecological

How do they do that? Through planes –If there is no air traffic– or thanks to generators that launch the compound from the ground taking advantage of the updrafts of air. The amount of silver iodide to be emitted is extremely low, which makes the method cheap: for every gram of silver iodide and at a temperature of around 10 degrees below zero, about a trillion freezing nuclei are produced that act on a million million droplets. Silver iodide has a crystalline structure that causes the drop to freeze. That ice crystal begins to grow at full speed and ends up raining. At first glance, it may seem that the sky is getting more and more cloudy, since in the process of freezing heat is transferred to the outside, and the clouds expand.

In Spain this method could be incorporated in areas such as the Central Cordillera, the Penibetica or the Pyrenees. Areas with a complex orography and where there are clouds. «In places like Murcia or Almería, silver iodide would not solve the problem of water stress. Seeding does not create the cloud. But if it exists, it favors it to discharge rain ». A few years ago, the Canal de Isabel II participated in a research project on snow increase and it was concluded that the Sierra de Guadarrama was a space with great potential for planting.

However, in Europe these technologies do not enjoy a great presence, among other reasons because in the countries of the center and north of the continent there is no concern about the lack of water resources. «The ballast of the drought is carried by the countries of the south. But the rumor mill has left us paralyzed. There is a false belief that if a cloud is intervened, when it continues to advance, another place can be deprived of rain. This is absolutely false, in no scientific report has it been proven otherwise “, recalls Sánchez.

Sowing can achieve that at a specific moment more water precipitates in the Madrid municipality of Pinto. But this does not mean that when the cloud rises above neighboring Valdemoro, its neighbors will be left without a downpour.

From 2012 to 2017, China spent the equivalent of more than a billion euros on weather modification programsAlthough for the next five years he plans to increase the amount to implement a plan that “although it uses a method that according to the WMO can increase precipitation by 15 percent, it has some propaganda. Results are difficult to evaluate. The statistics are not robust enough to affirm that the Asian country is going to decide when it rains in almost 5,000 million square kilometers, ”says Juan Esteban Palenzuela, from Aemet.

Something they are also ‘playing’ at United Arab Emirates. Until this year, the method that was being carried out in the Middle Eastern country was endorsed by WMO reports. As there are no mountains there, they acted on clouds closer to the ground and warmer. Instead of silver iodide they used hygroscopic salts (similar to common table salt) and instead of looking for the freezing of the drop, it was about accelerating the precipitation through the condensation process.

Drones in the desert

However, they are now promoting a system that is not scientifically endorsed by the WMO at the moment: ionization. Through drones, the cloud is acted upon by charging it electrically. «On paper, what is tried is that some drops are negatively charged and others positively and by attraction, condense and become rain. However, nobody assures that the drops are loaded with opposite signs. If this does not happen, instead of attracting each other, they would repel each other, ”explains Sánchez.

UAE is testing a new drone system to make it rain in the desert
UAE is testing a new drone system to make it rain in the desertABC

The reality is that, in 2016, more than 50 countries around the world embarked on artificial climate modification programs, due to the urgency marked by climate change. “Not only aimed at increasing snow or rain, but also at suppressing hail or dispersing fog,” says the Aemet expert.

China, the United States, Japan, Israel, Australia or the United Arab Emirates «have understood that atmospheric modification it is not an ideological question, but a future necessity. It will not be the panacea, but it contributes to the solution of the water problem, ”says Sánchez. In Europe, at the moment, it has only bet on hail control programs, which have been applied successfully since 79 in autonomous communities such as Madrid, Catalonia, Aragon or the Valencian Community.

But not all the methods that have been presented have been equally respectful of the environment. “In Colorado experiments have been done with a curious formula, but risky: propane at 20 degrees Celsius below zero in the clouds it produces a brutal freezing, but if it runs into a spark of fire it can cause a catastrophe, ”warns Sánchez.

Although what is truly dramatic, says this professor, are the frauds that have proliferated. «In Murcia thousands of euros were spent on sonic cannons that claimed to drive away hail. A joke that discredits other scientifically based methods. It is better to bring a dozen eggs to the Poor Clares than to shell out 150,000 euros to let chance do its thing.


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