Experts blame climate change for Dubai floods, say extreme rains not linked to cloud seeding.

 

Many wondered whether it was cloud seeding - a weather modification technique to induce rains - that led to flooding of Dubai, but scientists involved in such projects in India categorically dismissed any link, and meteorologists and climatologists rather blamed climate change for the record precipitation in arid West Asia.

Since parched UAE periodically conducts cloud seeding to increase level of its dwindling groundwater, extreme rainfall between Monday night and Tuesday evening raised questions on the artificial rain mechanism. The country received a record 255 mm of rain in less than 24 hours, flooding Dubai.

Though it rained heavily in neighbouring Qatar, Oman, Bahrain and Saudi Arabia as well, Dubai in UAE faced the maximum impact.

What is cloud seeding?

Cloud seeding is a type of weather modification that aims to change the amount or type of precipitation, mitigate hail, or disperse fog. The usual objective is to increase rain or snow, either for its own sake or to prevent precipitation from occurring in days afterward1. Here’s how it works:

1. Purpose: Cloud seeding is undertaken by dispersing substances into the air that serve as cloud condensation or ice nuclei. These agents encourage the formation of ice particles or water droplets within clouds.

2. Common Agents:

   • Silver Iodide: Often used for cloud seeding.
   • Potassium Iodide: Another common chemical.
   • Dry Ice (Solid Carbon Dioxide): Expands into a gas and can produce ice crystals at higher temperatures than silver iodide.
   • Hygroscopic Materials: These include substances like table salt, which can attract moisture and enhance cloud condensation.

3. Methods of Dispersion:

   • Aircraft: Cloud seeding can be done using planes that release seeding agents into clouds.
   • Ground-Based Generators: These generators disperse the agents from the ground.
   • Newer Approaches: Drones delivering electric charges to stimulate rainfall or infrared laser pulses aimed at inducing particle formation.

4. Effectiveness and Debate:

   • Despite decades of research and application, cloud seeding’s effectiveness remains a subject of debate among scientists. Some studies suggest it is “difficult to show clearly that cloud seeding has a very large effect” on precipitation enhancement1.
   • Environmental and health impacts are considered minimal due to the low concentrations of substances used, but concerns persist over their accumulation in sensitive ecosystems.

5. History and Applications:

   • Cloud seeding has a long history, with initial experiments dating back to the 1940s.
   • It has been used for various purposes, including agricultural benefits, water supply augmentation, and event planning.

6. Legal Frameworks:

   • Legal regulations primarily focus on prohibiting the military or hostile use of weather modification techniques.
   • Ownership and regulation of cloud-seeding activities are left to national discretion.

In summary, cloud seeding continues to be explored and applied worldwide as a tool for weather modification, despite skepticism and ongoing debate

How is it done?

• It is only effective in certain locations in a limited number of weather conditions. Also, cloud seeding requires existing clouds. It will not produce rain out of thin air.

• Not all types of clouds are suitable for seeding. Clouds must be deep enough and of a suitable temperature to be seeded effectively. The wind must also be below a certain speed.

• A seeder aircraft is flown to the seedable target area. The aircraft is equipped with cloud-seeding flares that can produce seed particles. When the aircraft reaches the target area, cloud properties are investigated by the aircraft. If found suitable, the cloud seeding flares are burned near the cloud base where there is upward air motion, which takes seed particles into the cloud.

• Seed particles aid the water molecules present in the cloud to condense around them rapidly. Large cloud drops are formed when small and large drops collide and coalesce, resulting in rainfall. 

• This weather modification technique has been utilised in various parts of the world, primarily in regions experiencing water scarcity or drought conditions. 

• However, the effectiveness and environmental impact of cloud seeding remain subjects of ongoing research and discussion.

Cloud seeding in India

• Last year, cloud seeding experiment in Solapur region of Maharashtra resulted in 18 per cent more than normal conditions, according to a study published in the Bulletin of the American Meteorological Society (BAMS). Scientists from the Indian Institute of Tropical Meteorology in Pune and other institutes conducted the study.

• In June 2023, IIT-Kanpur successfully conducted a test for artificial rain via cloud seeding over a limited area on the campus.