In 1946, American scientists conducted the first cloud seeding experiments. They made the snow fall in a fridge and then moved on to full-scale tests. With an airplane, they dispersed silver iodide in the water vapor of a cloud. The silver iodide agglomerates the droplets, forming drops or flakes, depending on the temperature. Between 1947 and 1952, the United States army financed no less than 255 experimental flights: this is the Cirrus project.
The army continued its research and launched Operation Popeye in 1966. Planes then disseminated tons of silver iodide over the Ho Chi Minh trail – a set of roads used during the wars of Indochina and Vietnam by the Viet Minh to transport equipment from north to south — to intensify the monsoon and slow down the enemy. The operation was made public in 1971 and went poorly. A convention of the United Nations (UN) banning military weather modification, dubbed the Convention ENMODcame into force in 1978.
- During the Vietnam War, the United States Army used cloud seeding in an attempt to drown the Ho Chi Minh Trail, which was used for transporting goods. Wikimedia Commons/CC0/Stewart, Richd W. “ Deepening Involvement, 1945-1965, » Center of Military History, United States Army
Sowing rain, from Beijing to Addis Ababa
This convention did not prohibit the use of climate control for civilian purposes. China is now the world leader in this field. In 2008, the country made every effort to ensure good weather during the Olympic Games. A hundred soldiers and two planes were mobilized. This sowing operation cost half a million dollars.
In 2016, China considered a gigantic climate modification program. The country wanted to deflect water vapor from the humid south to the arid north. Four years later, Beijing promised to build hundreds of turbines on the Tibetan plateau to increase the amount of snowfall. The megasystem should be operational in 2025. Difficult to obtain more detailed information. But the announcement was enough to cause concern in neighboring countries, including India. Ten major Asian rivers originate in the Himalayan heights.
- By 2025, the Tibetan plateau could be the scene of the largest cloud seeding project in the world. Unsplash/CC/Jiasong Huang
Since the 2000s, cloud seeding programs have multiplied. United Arab Emirates, India, Morocco, Australia, Ethiopia… around fifty countries use this technology. In Europe, it is used to fight against hail. Twenty French departments have generators deployed in the event of a weather alert. These more than 1,000 generators send silver iodide to high altitudes to reduce the size of hailstones that hit farms. On April 13, they operated in twelve departments. It is an association, Anelfa, which oversees these operations. Its management emphasizes that they allow beneficiaries to reduce the cost of their hail insurance. The insurers consider that this preventive measure justifies a less salty addition.
Despite their success with governments and insurers, cloud seeding programs leave the scientific community dubious. If they can work in the laboratory or on occasion, it is difficult to estimate their effectiveness, especially if they are deployed on a large scale.
Israel has seeded clouds in the north of the country for six decades. Researcher at Tel Aviv University, Pinhas Alpert compared rainfall levels between seeded areas and areas without human intervention from 1969 to 2007. His goal: to understand if the program increased the amount of rain in a statistically significant way . His study has disturbed seeding advocates, and his results have contributed to Israel shutting down the use of the technology altogether in 2021 for lack of return on investment.
The Israeli researcher explains that it is extremely complicated to predict the behavior of rain. The phenomena at work are too vast. “ We do not yet have a model to describe the interactions between aerosols and clouds on a large scale, at the synoptic scale. » Same story on the American side. “ The increase in precipitation is small, to say if the rain or snow fell naturally or if it was triggered by the seeding remains difficult »wrote, in March 2022, William R. Cotton, professor of meteorology at the University of Colorado.
- Abu Dhabi, capital of the United Arab Emirates, in April 2021. Flickr/CC BY–CN–n/a 2.0/Nasa Johnson
For Pinhas Alpert, if certain countries like the United Arab Emirates persist in this way, it is because the fertile crescent is drying up. Rainfall amount decreased by 20 % over the last three decades. An inhabitant of the United Arab Emirates consumes an average of 500 liters of water per day, more than three times the world average consumption. Faced with this impossible equation, the idea of artificially increasing the amount of rain is attractive, even if it means taking the risk of creating tension. In 2018, Iran accused the United Arab Emirates and Israel of stealing “ her ” rain.
An increasingly political weather
Sowing rain is not the only avenue of meteorological innovation being studied. Some states propose to solve the problem of rising temperatures by modifying the composition of the stratosphere. Others, to fertilize the oceans so that they store more CO2. These “ solutions » worry the scientific community, environmentalists… and members of international institutions.
Tracy Raczek, former climate adviser at the United Nations (UN), underlines the risks of this race to control the weather: “ The first threat comes from the fact that their deployment in one territory could affect another. The second is the difficulty of distinguishing a negative effect on a neighboring country from an insignificant effect. The last is the ease with which these technologies could be deployed in an officially peaceful manner, but secretly be used to harm an adversary. » The expert calls on the international community to dust off and enrich the Convention ENMOD — formally Convention on the Prohibition of the Use of Environmental Modification Techniques for Military or Any Other Hostile Purposes — of theUN, to regulate the use of these technologies in times of peace. With the environmental crisis, the weather is becoming a geopolitical subject.
Costly, misunderstood, potentially fraught with political consequences, why do these technologies continue to seduce States? ? Climate control projects could be symptoms of a deeper evil. The philosopher Pierre Charbonnier observes the way in which capitalism tries to adapt to climate change. He recalls that capitalism bases its legitimacy on a promise: to create a society of material abundance, where everyone is free to fulfill themselves by consuming the goods at their disposal. This promise implies a specific vision of resources, is that innovation abolishes natural scarcity.
With machines, the agrarian and then industrial revolutions, humans freed themselves from the constraints of nature. In an interview with France Culture, Pierre Charbonnier explained in 2021 that the environmental crisis shows the limits of this model: “ We are committed […] on the path of modern societies, which we realize leads to a dead end. » Because in practice, the Earth cannot support infinite growth.
To admit this impasse is to admit that it is necessary to reinvent the meaning that our societies give to freedom. For example, by considering water as a precious resource whose use must be better regulated. Even if this must be detrimental to freedom of enterprise when the latter leads to overexploitation of the resource. It is to invent a freedom within the limits of natural resources. If more and more States are believing in the promises of sowers of rain, it is because they do not require a radical change. For meteorologist William R. Cotton, in the face of the environmental emergency, pretending that we can make it rain on command is a “ political placebo ».