The cloud seeding phenomenon

Rain clouds hovering over a field
Rain clouds hovering over field (Photo credit: Jean-Luc Crucifix)

When you come from the islands the abundance of rain is no caveat. Needless to say, the rain is so plentiful that we complain when it pours and stay indoors all day long. In Trinbago we say, “it’s raining bucket ah drop” meaning we could get buckets full of water because the droplets seem so big.

This is not the case for a lot of countries around the world. I first heard of “cloud seeding” during the Beijing Olympics but was not worried a tad bit about it, until now. Now I’m no scientist, but from research I found “cloud seeding” to be a type of weather modification that aims to change the amount of precipitation that falls from clouds by dispensing substances into the air that serve as cloud condensation or ice nuclei, which alter the microphysical processes within the cloud. 

Some say it’s the enhancement of natural precipitation. So, to understand the process of cloud seeding, it’s better to understand clouds. As we already know clouds are a bunch of water droplets or ice crystals floating in the sky. The water droplets are too small to fall as precipitation but large enough to form the cloud that is visible to the human eye. The cloud droplets are super-cooled or below freezing but they remain liquid. Sometimes these droplets are just floating around pushing past each other and not sticking together kind of like a missed connection. Other times these droplets bump into each other like commuters on a train during a busy rush hour. The water vapors collide and stick to particles floating in the air. It could be dust, smoke particles or meteoric debris. 

So cloud seeding can basically produce what we want more or less of, more snow, more rain or smaller hail pellets. This process can be done by introducing a seeding agent (usually from an aircraft or drone) through pyrotechnic flares. The mission of those flares is to deliver the condensation nuclei that encourage more collisions and group huddles of ice crystals inside the cloud.

Why would we even want to do this and who does it benefit?

The implementation of cloud seeding may increase harvesting and make food more available from a wide variety of crops for the ever-growing human population. Cloud seeding is mostly seen as a tool to fight drought or other low moisture conditions. Hail suppression and fog management are additional forms of this activity that you see happening at airports when challenging weather conditions exist.

No amount of precipitation can go without consequence. Some of these disadvantages include the dangerous substances released into the atmosphere.  There are times when the process doesn’t work, when the solid carbon dioxide or liquid propane is released and these particles become part of the local environment. We do not yet know the adverse effects on the human body, food and water systems. Cloud seeding is not 100 per cent guaranteed and even scientists disagree on its overall effectiveness. Then there are also the effects on some regions of the world that may not have any opportunities to use this technology. Some regions receive most precipitation events through thunderstorms, an event that aircraft aren’t always recommended to fly through thanks to the presence of lightning.

Cloud seeding is an expensive venture which means the expense of producing additional precipitation could be higher than the economic benefit it provides.  When clouds receive seeds that encourage more rainfall in a specific area, then that activity could rob other regions of the moisture that they’d typically receive and change the patterns of what other people receive hundreds of miles away.

Subrina Hall Azih is a Trinidadian Educator residing in New York.

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