As devastating droughts threaten regions across the world,
scientists have proposed a solution that sounds like science fiction.
If the water doesn’t come during the winter in the form of snowfall, and doesn’t come during the spring in the form of rain...
what if we just make it rain? Literally?
While this may seem like a far-fetched fix, this idea is actually based on technology that’s been around since the 1940s.
It’s called cloud seeding, and it is what it sounds like:
Tiny particles are released into the air, either by an aircraft or an automated machine.
This technique relies on the answer to one key question: where do clouds come from?
The simple answer is that clouds have nuclei, but not the kind that atoms have.
Water evaporates into the atmosphere as part of the water cycle.
That evaporated water accumulates around micro-scale solid or liquid particles made of dust or pollen...or even bacteria.
These are called condensation nuclei.
As more and more water vapor clings onto a condensation nucleus, it starts to form a cloud droplet.
Once the droplets get big and heavy enough, they fall from the cloud in the form of precipitation—
that can be rain, snow, even hail!
The scientists who came up with the idea of cloud seeding assumed that the limiting factor to how big clouds get
or how likely it is they’ll precipitate is these condensation nuclei.
So, they decided to add some.
They chose silver iodide particles because their crystal structure is assumed to be very similar to that of real ice,
providing a scaffold for water to cling to.
Adding these particles to growing clouds helps water vapor freeze around the nuclei at higher temperatures than it would naturally,
making precipitation come faster.
And after its invention, cloud seeding was widely adopted.
It was put to work by the U.S. government—most notably during the Vietnam War, with the goal of flooding enemy supply routes.
But in the 70s, the UN adopted a resolution to ensure that all its member states would only use weather modification—
like cloud seeding—for peaceful purposes from then on.
So, it may sound like a simple and effective solution:
Just make more clouds to make more rain, right?
But there are four main pitfalls that mean we gotta switch the faucet off on that excitement.
One: we still don’t really know if it works.
Or if it does work, how effective it is.
See, once you’ve seeded a cloud, it’s tough to say how much precipitation that cloud would have yielded if you didn’t seed it.
One recent study DID find that some seeding produced snow where it would not have fallen otherwise...
but the amount of snow was negligible.
And in areas where precipitation was expected, it’s still hard to say if seeding made a difference either way
in what would have fallen naturally.
We also don’t actually know HOW water vapor forms around condensation nuclei into cloud droplets in the first place—
although there’s a lot of interesting research into this right now too, so...
there are just a LOT of unknowns.
Problem two: You can only seed clouds that are already there—
you can’t make clouds appear out of thin air.
There has to be enough water vapor in the air already for cloud seeding to work,
so in extremely dry areas already devastated by drought,
this isn’t much of a fix.
Three: We don’t yet fully understand the implications of adding seeding chemicals to our water cycle.
Take silver iodide, for example.
Silver is toxic to many aquatic organisms in large doses, so we need to monitor the levels of these compounds
that may make their way into the water cycle.
And while dry ice, potassium chloride, and more can also be used for cloud seeding, depending on the situation,
the environmental effects of these will need to be considered too.
And four: Does cloud seeding upset the balance of nature even more than climate change-induced drought already has?
Some scientists worry that increasing the volume of clouds in one place will pull moisture from another area,
interrupting rain that could have fallen there instead…but again.
The dynamics at play in clouds are so complex that it’s really hard to say where rain would have fallen if we had left everything alone.
The fact remains that by 2030, almost half the world’s population will live in highly water-stressed areas due to climate change.
And at least 52 countries all over the world—including the U.S., China, India, and Russia—
have invested in weather modification technologies in the hope of bending the weather to their will.
So, while we investigate if and how cloud-seeding could help,
it’s important to remember that it’s really just a band-aid.
Experts say that if these strategies are seriously considered as a drought solution,
they must be part of a larger plan that involves smart water management.
And even if things like cloud-seeding will help, they treat a symptom, not the cause.
To ensure long-lasting solutions to droughts worldwide, change that will actually make a fundamental difference,
we have to address the root causes of the climate crisis too.
If this video left you thirsty for more info on clouds, check out this other video on cloud complexity here,
and let us know down in the comments what else you’re interested in learning about weather modification.
Subscribe to Seeker to keep up with all your news on weather and climate, and as always, thanks for watching.
I’ll see ya next time.