The practice of cloud seeding and the disaster in Dubai

For several years we have been talking about climate change, increasingly hotter summers, days of uninterrupted rain and crops ruined by drought. These remarkable events make it clear how current change is and how necessary it is to put actions into practice to safeguard people and nature from the hostility of the climate.

In the last summers, record temperatures and sporadic rains have caused big damage to crops, leading to poor harvests and economically damaging farmers. In order to overcome the problems of water scarcity, many countries have started building infrastructures for the collection and conservation of winter precipitation by creating reservoirs. In other countries, where rainfall is generally scarce, other actions have been taken, such as the use of the cloud seeding technology.

How cloud seeding works

Cloud seeding, usually translated as “clouds insemination”, was born in the 1940s from the idea of some American chemists and meteorologists. This revolutionary practice gained ground at the end of the 1950s when in the United States started to be used in order to help farmers irrigate their fields, to increase the water reserves of hydroelectric power plants and to fill ski resorts with snow. The cloud seeding technique exploits the natural principle of condensation nuclei, that are present in moisture-laden clouds. These are tiny hygroscopic particles capable of absorbing water molecules which allow the droplets that form the cloud to increase in volume, condense and then become rain.

In 1946, Vincent J. Schaefer, American chemist and meteorologist, discovered that dry ice, by virtue of some of its intrinsic characteristics, could act as a condensation nucleus for water vapor particles present in clouds. Around the same period, his colleague, the climate scientists Bernard Vonnegut, discovered that silver iodide molecules were also capable of acting as a condensation nucleus, like fragments of dry ice.

The most widespread cloud seeding practice exploits Vonnegut’s discovery, introducing silver iodide nuclei into the clouds as a condensation element. In fact, siver iodide, has an extremely compact molecular structure that seems to be ideal for binding with ice particles and for increasing the volume of rainfall. Then, the insemination can take place both from the ground, with special cannons that shoot the compound from below, and through airplanes, which, flying above the cloud banks, sprinkle the particles on their surface.

From data published by research groups in the sector, it’s estimated that the practice of cloud seeding can bring an increase in annual precipitation of between 15% and 30%. For this reason, always more countries are relying on this technique in order to combat the water crisis and improve the climate situation in the driest places.

The extraordinary rain in Dubai

Countries such as India, Indonesia, Malaysia, Thailand and the United Arab Emirates (UAE) have been using climate manipulation technologies for years, in order to increase the water reservers at their disposal.
The United Arab Emirates, in particular, launched in 1990 a Rain Enhancement Science Research Program (UAEREP), which since its start has been concerned with promoting scientific progress, the development of new technologies in this sector, and ensuring access to water in arid and semi-arid geographical areas.

Although the United Arab Emirates has successfully practiced cloud seeding for years, last month extraordinary rainfall hit the country causing significant damage.

On April 16, in Dubai, a violent storm hit the city, which led to over 140 millimeters of rain falling in just 24 hours. The images of the submerged city and the cars dragged by the current have shocked scientists all around the world, who are now wondering whether the cause of all this can be attributed to the intensive use of cloud seeding. The emirate’s National Meteorological Center confirmed to the Bloomberg agency that it had lounced seeding expeditions the days before the natural disaster. However, according to the experts consulted by the BBC, despite the violent flood occurred a few days after the Centre’s operation, cloud seeding may have contributed to the storm marginally, if not minimally, and therefore it would be wrong to attribute all the responsibility for the disaster occurred to it.

Although this time cloud seeding technology doesn’t seem to be directly responsible for what happened, there isn’t full knowledge of the possible negative impacts of this technology. Therefore, a working group within the World Meteorological Organization (WMO) has been created to investigate possible undesired effects and monitor the growing use of this practice.

Although currently there isn’t a complete knowledge of the consequences that this technology could bring, for many countries cloud seeding represents an effective tool to improve water conditions in drought areas. In facts, in countries such as Mexico and the western United States, this technology represents a cheaper alternative to other solutions like the desalination of sea water taken directly from the ocean.

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Translated by Stefania Errico