Cloud Seeding: What Danger?

Controlling the weather to make it rain on command or to combat hail has long been a human fantasy. Since the 1950s, this dream has become a reality thanks to the technique of cloud seeding. However, this manipulation of clouds to alter the weather is not without danger. Explanations.

1- What does cloud seeding involve?

Cloud seeding is a technique that involves adding aerosols or small particles to clouds in order to influence precipitation and modify the weather.

Most often, silver iodide particles are used. They are released by airplanes flying over the clouds or sent from the ground by huge cannons called generators. In both cases, the particles released into the clouds interact with the water vapor already suspended in the air.

This human manipulation allows for controlling rainfall, dispersing fog, or even reducing the size of hailstones and thus the extent of damage that hail could cause.

2- When did cloud manipulation begin?

The technique of cloud seeding was developed in the United States in 1946. It was first applied the same year to induce artificial rain during a severe drought in the New York area.

Starting in the 1950s, this manipulation of clouds was also used to reduce the size of hailstones and minimize the damage caused by hail on crops.

In 1951, the National Association for the Study and Control of Atmospheric Pests (ANELFA) was created in France to apply this technique and measure its effects. Even today, this association conducts operations to trigger rain and hail at the request of French farmers.

In the 1950s and 1960s, this technique was also used for military purposes during the Indochina War and the Vietnam War. It was used to trigger rain to slow down enemy troops. When this information was made public in 1971, a UN convention was convened and prohibited climate modification for military purposes.

3. Which countries use cloud seeding?

Today, the technique of cloud seeding to combat hail is used on all continents, from Australia to North America, including Italy and Brazil.

Meanwhile, Russia and China have already used this technique to extinguish forest fires or for more trivial reasons. These two countries are known to trigger rain the day before major events (such as the opening ceremony of the Beijing Olympics or military parades) to ensure favorable weather on the big day...

While China is considered the world leader in cloud manipulation, more than 50 countries around the world are interested in this technique and invest money in cloud control. This is especially true for countries in arid and semi-arid regions of the planet, such as Australia, the United Arab Emirates, Morocco, and Ethiopia.

As early as 2004, the World Meteorological Organization counted more than 100 artificial weather modification projects worldwide. With climate change, the temptation to control the weather is likely to increase.

4- What are the dangers of cloud seeding?

Even though cloud seeding has been used for more than half a century and has proven its usefulness in certain circumstances, this cloud manipulation technique is controversial.

It fulfills humanity's age-old dream of controlling the weather and using it to its advantage in weather-sensitive activities such as agriculture or organizing outdoor events. But it is not without consequences on the environment and the geopolitical balance of the planet.

On one hand, silver iodide used to trigger precipitation is among heavy metals and constitutes a toxic substance for aquatic species, which has led scientists to seek alternatives like calcium chloride.

On the other hand, we still do not know how to measure and control all the consequences of this technique, including the risk of triggering excessive rainfall and floods or the risk of drying out a neighboring region. In 2018, Iran accused the United Arab Emirates of "stealing its rain."

Due to the potential harmful effects on the environment and the geopolitical balance of the world, some people like jurist and novelist Mathieu Simonet advocate for clouds to be considered a common good of humanity. If they were ever listed as a UNESCO World Heritage site, no country could unilaterally decide to manipulate them...