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Up in the clouds

This fortnight there has been so much science and ecology in the news we barely know where to start! Scientists have reminded us that we should eat less meat (from the health, animal welfare and environmental points of view), the cosmos may not be stable (but it’s lasted 14 billion years so far so it’ll probably be OK for a bit longer) and whales are reacting well to a reduction in noise from ships near Boston.

But the headline that caught our eye was this one: “Is cloud seeding preventing further flooding in Indonesia”. What, we thought to ourselves, is cloud seeding? Well, it turns out that it’s been here for a while, and what happens is that planes are flown above clouds and scatter salt (amongst other things) – this salt encourages the cloud to absorb more water, meaning that it becomes saturated and rains out all its water quicker.

We had a look into this, and there really isn’t a lot of evidence of whether it works, and if it does, what effect it has on local weather systems in the long term. There is some evidence that it has worked in Tasmania, but the people who investigated it urged caution in its use. The problem with studying the technique is that it is impossible to know where and how much rain would have fallen without having seeded the clouds.

Here at the blog we find ourselves feeling quite uneasy about this. On the one hand, if we can use such techniques to avert natural disasters (such as floods or landslides) then that is obviously a good thing, from both the human and environmental point of view. However, excessive flying of planes and scattering chemicals in order to change the local weather system? Surely this a) detracts from the bigger picture that if we don’t stop climate change now then there will be so many more natural disasters in the future, b) flying planes adds to global greenhouse gas emissions, and c) surely adding salt to rainwater will affect the local ecosystem where the rain falls?

As with everything else, this technique is open to corruption and misuse – imagine you live in an area with very little rainfall, but you need water to drink and to water your crops. Now imagine the effect on you if someone who lived in an area near to yours was able to effectively steal the water from clouds that were coming your way? If this technique works then there are a multitude of ways that it can be misused.

Wouldn’t it make more sense to put our efforts in to slowing climate change, rather than trying to stick the broken bits of our planet back together with a plaster?


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Blog post by Linda Seward of Seward Technical Writing, providers of original science content.

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