Several Gulf countries experienced torrential rains at the start of the week. The city of Dubai, in the United Arab Emirates, is particularly affected, giving rise to impressive images.
Since Tuesday, a theory has been popular both in certain conspiracy circles and in the press: these floods could have been caused by cloud seeding – a technology which aims to influence the weather artificially, by sending chemicals in the clouds.
The United Arab Emirates are in fact known for developing this practice for several years, to deal with drought. For conspiracy communities, this very real technology is mixed with that of chemtrails, this conspiracy theory which claims that the trails left in the sky by planes are in fact harmful chemicals.
Conflicting claims from the United Arab Emirates
It must be said that the idea that floods are the cause of cloud censing is not new, and was especially supported by the comments of a meteorologist from the National Center of Meteorology (NCM) of the United Arab Emirates. . An article from the American media Bloomberg published on Tuesday in fact cited the words of Ahmed Habib, a meteorologist from the NCM, making a link with seeding flights on Monday and Tuesday.
Information which he finally returned to in an article in the American media CNBCasserting that “ [les] “pilots had flown missions as part of regular protocol, but had cast no clouds.” In the same article, NCM Deputy Director General Omar Al Yazeedi stated that the center “did not carry out any seeding operations during this event”. When contacted, the NCM did not respond.
“The rains were already here”
According to experts interviewed by 20 minutes, the cause of the floods at the start of the week is not to be found in cloud seeding either. This is particularly the opinion of Andrea Flossmann, professor at Clermont Auvergne University and co-chair of the World Meteorological Organization’s team of experts on weather modification. “You can’t sow where there is no humidity. Seeding is just a little extra push to get it rocking when there is sufficient moisture. In this case, the rains were already there,” explains the scientist.
Conclusions which echo those of Olivier Boucher, climatologist and deputy director of the Pierre-Simon Laplace Institute. “In the case of the floods in Dubai, [le fait que l’ensemencement ait joué un rôle] is extremely unlikely. These are air masses that were so loaded with humidity that it was going to rain anyway.” The expert also points out that seeding clouds does not create more precipitation. “The goal is only to trigger the rush. There is also no memory, so no long-term effect of this seeding. »
For Olivier Boucher, the heavy rains are due to “a meteorological system undoubtedly quite unusual, but not impossible”, with “probably a link with global warming, which increases the probability that this type of event will happen, but it would be necessary a study to confirm it. Finally, Dubai, which is highly urbanized, undoubtedly has “insufficient drainage of the rainwater evacuation system, which was not designed for large quantities of water,” adds the climatologist.
Relative efficiency
In addition, “the big problem is that of measuring effectiveness” on a scientific level, explains Andrea Flossmann. “No two clouds are alike, even in similar atmospheric conditions. So it’s very difficult to prove that it was because of the seeding and not just naturally. Recently we have made progress on this but only in particular cases. »
As Olivier Boucher explains, there are “two main seeding techniques”: “The first is based on the injection of silver iodide particles, which is aimed at so-called cold clouds, where there are liquid water at negative temperatures. The idea is to transform these liquid water droplets into ice crystals so that they aggregate, become heavier and trigger precipitation. Today, research shows that in this case, when it is seeded at the right time and on the right type of cloud, there can be locally 10 to 15% more precipitation compared to what would have happened if we had not sown. »
However, “this is not the type of seeding used in Dubai, contrary to what may have been written in the press. They have another technique, because it is too hot, which consists of trying to inject particles which are giant condensation nuclei, which will attract water, to generate droplets larger than the others, which will be able to continue to grow and trigger precipitation. On this technique, I have not seen any studies which showed that it worked,” explains Olivier Boucher.
In vogue since the 1940s, this idea had “a little bit been forgotten,” explains Andrea Flossmann. Before “more and more countries turn to it, with the consequences of global warming. » The Gulf countries, like the United Arab Emirates, have been “particularly active” in these programs for around ten years.