This article has been prepared by Maldita.es for 'La Vanguardia' within the framework of the Clima Informa project to prevent misinformation related to climate and the environment.
“The desperation of the drought made us think that there were planes that avoided the rain.” Felipe Gómez, a farmer from Castillo de Aguarón (Zaragoza), tells how in the spring of 2023 the idea that someone was manipulating the climate caught on among farm workers. At the end of May last year, virtually the entire Ebro basin was in prolonged drought and, although the rains are better this year, the message that the drought is being artificially caused has continued to circulate, especially during the farmers' protests.
“There are people who are convinced. And I was until I started talking to other people,” continues Gómez, who stopped believing in anti-rain fumigations when asking some friends who worked at the Zaragoza military base. “Now I tend to think that when it wants it rains and when it wants it doesn't rain. But there are many people, many, many, many people on social networks – in Catalonia, where it has rained very little, in Alicante… – convinced that they are manipulating the climate.”
As some tell it, it is a story full of epic: the governments of the world secretly join forces to control the resource on which we humans depend most, water, but only a few realize the reality. From a psychological point of view, it is common for these theories to be easier to believe and internalize than the complex scientific processes by which it stops raining in one region or another.
“About the small planes?” It is the phrase with which many respond when asked about this topic. But in reality there are no planes or contrails that cause drought in Spain.
Of all that is said about the supposed control of the climate, there is something with a real basis: the seeding of clouds with silver iodide, which is currently practiced by the State in agricultural areas of Aragon and Madrid to reduce the impact of hail. on crops.
The way it works is as follows: in the hours before a hail storm, several silver iodide generators installed on the ground release a small amount of this chemical compound into the ascending air current that is rising towards the cloud. The key is that the crystal structure of silver iodide is similar to ice. Therefore, if it reaches the cloud at the right time, the number of points around which a ball of ice or hail forms will increase, giving rise to more but smaller hail balls, explains José Luis to Maldita.es. Sánchez Gómez, research physicist at the University of León. “If you're lucky, the small hailstones can thaw” and remain as rain, the expert continues.
Cloud seeding does not affect the climate, which are the average conditions of temperature, precipitation, winds and other elements that are recorded in a place over several years, but rather the weather, that is, those same conditions but at a specific time. Furthermore, although other countries do use them, in Spain there are no small planes or planes involved in the fight against hail and therefore cloud seeding does not leave trails.
On the other hand, “it is not a miraculous system because the hail continues to fall,” clarifies Fernando Peligero Domeque, managing director of the Aragon Anti-Hail Consortium. “The most effective mechanism is to put a mesh over the crop, but that is very expensive. However, in cloud seeding the efficiency is very high because at low cost it is possible to reduce the energy with which hail falls,” he explains.
In Used, a small municipality south of Zaragoza, the current mayor is also the creator of the Platform “Who dries our fields?”, which he promoted convinced that the anti-hail cannons in his region and some small planes were behind the lack of rains. The platform called for an investigation in this regard and expressed concern about the effect of silver iodide on the environment. In 2016, the Campo de Daroca region, which includes Used, stopped being part of the Aragon anti-hail consortium and currently does not practice cloud seeding. His story symbolizes some of the most common misinformation surrounding this technique.
Silver iodide cannot cause drought because its objective is precisely to force rain. By increasing the freezing nuclei of the cloud “the amount of water it contains does not change, only the way in which it freezes” so that the hailstones fall smaller, explains José Luis Sánchez. Scientific studies that have analyzed this technique in different places around the world, such as those carried out in China in 2010 and 2021 and in Spain and France in 2016, agree that both the objective and the result of planting is an increase in precipitation.
Another reason is that this technique is activated very few days a year. In both Aragon and Madrid, the anti-hail campaign covers the months from May to September, but the generators are only turned on if there is a risk of hail. “There are less than 10 days of lighting per campaign. And on those days, the ignitions last two, three, four hours,” explains Vicente Díez de la Torre, the agronomist of the Madrid Agrarian Chamber, which maintains a network of 14 generators. In Aragon, according to what the consortium tells Maldita.es, there are currently 32 operational generators that are turned on between 30 and 40 days per campaign, that is, around 10% of the days in a year.
“Our anti-hail network has been in operation since 1976. In 2022 we began a renovation of the network, but, as always happens with these things, the deadlines were delayed and we stood at the beginning of the campaign without having the equipment installed. That year there was a drought and everyone blamed the Agrarian Chamber, but it was exactly the year in which we did not defend against hail for a single day. In 2023 it did turn on and we had a very humid October,” the engineer from the Madrid agricultural chamber adds as an anecdote.
On the other hand, regarding the alleged use of small planes, both the Aragon anti-hail consortium in statements to Maldita.es and the documents published by the platform itself Who dries our fields? show that in the 1980s small planes were used in two cloud seeding experiments next to the Zaragoza airport. But according to Fernando Peligero they have not been used again for anti-hail defense and, in any case, silver iodide cannot dry the clouds.
Several recent studies have analyzed the possible environmental impact of cloud seeding with silver iodide, two of them led by Jesús Causapé, a hydrology expert at the Geological and Mining Institute of Spain who is also a native of Used and a personal friend of his current mayor.
According to the results obtained so far, both in those recent studies and those that began in the 1970s, the concentration of silver iodide in the environment is too low to be harmful. On the one hand, studies carried out under laboratory conditions have proven that “large quantities” of silver iodide accumulated in an area can “moderately” affect its fauna and flora. On the other hand, studies carried out under real conditions have not found sufficient concentrations of silver iodide in the environment to cause this impact.
Among the latter is the one published by Causapé in 2021. The work analyzed the concentration of silver in rainwater both in the areas of Zaragoza where cloud seeding is still being carried out and in those that left the consortium in 2016. Except in the Samples taken a few meters from the generators, concentrations were often below legal thresholds.
In a second study, Causapé investigated the possible accumulation of silver in water, fauna and flora, concluding that the levels found were lower than expected after decades of anti-hail campaigns. But they did find a certain concentration of the compound in some cereal fields and in two sheep. This shows that silver “is assimilated by flora and fauna, so it is clear that it can be transmitted to the food chain,” Causapé explains to Maldita.es. However, “at the moment and although there is not much legislation, it seems that the levels are not worrying,” continues the expert.
“We continue to investigate where the silver iodide emitted for so many years goes because it is unknown whether it is not accumulated in wetland sediments,” continues the scientist. For now, the hypothesis is that this silver has been constantly absorbed by the plants and that this has prevented environmental deterioration in the area studied, which includes the protected Gallocanta lagoon.
While cloud seeding is a true but distorted story, about the supposed climate control there is a completely wrong and misinforming story: the chemtrails conspiracy. This idea was born in the United States in the 1990s and argues that the condensation trails left by airplanes when flying are actually the trail of different chemical substances that are sprayed on the population for various purposes, from spreading diseases to stopping the rain.
Everything has already been explained about this conspiracy theory and its lack of logic, but the truth is that almost 20% of the Spanish population believes that humans are changing the climate by fumigating from airplanes, according to a survey by the international organization More in Common provided to Maldita.es. The idea has a special reception among Vox voters (35% believe this hoax), although it is also common among young people and in the rural world.
When talking about these supposed climate modifications, the word geoengineering is also frequently used. But again, there is a little bit of truth in this and a lot of lack of context. Geoengineering is a new field of study that investigates whether it is possible to counteract global warming by causing a cooling in the atmosphere on a planetary scale. This cooling would be achieved by reducing the amount of solar rays that enter the Earth, for example, by introducing tiny sulfur crystals into the clouds so that they function as a mirror to the outside, imitating what happens naturally after some volcanic eruptions.
This would be the most studied and with the most potential of a set of techniques that have been investigated for more than a decade. But currently “there is no mature technology to apply the options for modifying solar radiation,” as indicated by the United Nations intergovernmental group for climate change, the IPCC, which has exhaustively analyzed the four main ones. The group of experts concludes that these techniques could offset global warming, but that their potential to introduce new risks to the planet is still unknown.
The European Commission said last summer that it “does not consider geoengineering to be the solution to climate change because it does not address the root of the problem,” which is the increase in greenhouse emissions as a result of human activities. Furthermore, it sees the modification of solar radiation as “an unaffordable risk for humans and the environment” because its “impacts” are unknown, although it advocates continuing research.
It is common for disinformers to take a real starting point (on a small scale a cloud can be made to discharge water or airplanes leave contrails in the sky) and exaggerate it to make people believe something totally false (drought is because we fumigate). If we add to this the mixture of concepts and technical complexity, it is easier to confuse people, since untangling that tangle requires time that most do not have.
Luis Aguado Alba, from More in Common, says that around 70% of the Spanish population continues to think that climate change “is a real problem and is caused by human action,” according to a survey that was repeated in 2021 and 2024. "Despite the expansion of conspiracy theories, the great consensus around climate change in Spain has not been affected and 'pure' denialism is totally residual, but it evidently muddies the debate and forces us to dedicate time to pedagogy." or to deny hoaxes.”
“They are beliefs that have no reason to exist and make us spend money proving what others have to prove,” says Fernando Peligero. He says that the consortium has called meetings to explain what they do together with university professors to explain it. "But you go to an audience of 300 people and after giving the explanation, a rancher or a farmer jumps up and tells you: 'You can say what you want, but when the storms come and I see two airplanes, the storms disappear, and I don't I believe nothing he says.' Against that… what can you do?”
