Have you ever wondered… how you can artificially make it rain?
While we still have not reached the point where we can control the weather (and thank goodness for that!), it does seem as if the winds are changing. The technology of cloud seeding has enabled Mother Nature’s force of precipitation (i.e. rainfall, hail, snowfall, etc.) to be artificially induced. Before understanding what cloud seeding is, let us first take a look at what clouds are and how they cause precipitation.
The fluffy pillows that you see flying on top of you are basically a bunch of water droplets or ice crystals floating in the sky. Clouds are formed from the evaporation of water, which then rises, cools, and condenses. These droplets, while large enough to exist as clouds, may still be small to fall as precipitation. In most regions, these droplets are super-cooled. This means that they are below freezing point yet remain liquid. For the most parts, these droplets require the presence of solid particles to which they can adhere to. These particles (also referred to as condensation nuclei) range from dust and smoke particles to meteoritic debris and enable the tiny droplets to accumulate as they bump around. The drop eventually grows heavy enough to fall, in form of precipitation.
In cloud seeding, chemical agents are delivered to encourage the collision and huddling of droplets and ice crystals inside the clouds to induce rain. Airplanes, equipped with pyrotechnic flares, are used to scatter chemicals, like salts, dry ice, or silver iodide in the air. These agents are spread when the plane flies over a cloud layer, with the assistance of winds, swirling behind the plane, that helps distribute the particles. With enough nuclei now present, the supercooled droplets in the clouds can transition from liquid to solid states, causing crystal structures to grow and eventually fall on Earth.
As exciting and promising as this technology seems, cloud seeding is disputed for its overall effectiveness in actually inducing precipitation. This is because it is very difficult to conduct studies and gather statistically solid data on this approach and answer the crucial question of whether it would have rained the same way or not, without any intervention. Moreover, many researchers also question the possible impacts this technology may have on our health and environment in the long run. Nevertheless, there are numerous cloud seeding projects operating across the globe, especially in dry regions that are plagued by a lack of water. UAE, for instance, is currently operating such initiatives on a national level and actively funding projects that study rain enhancement technology, to combat its arid climatic conditions.
