Cloud seeding locally and temporarily enhances precipitation
Dispersing certain minerals into clouds with favorable conditions, condenses or freezes small, naturally occurring water droplets into drops or snowflakes big enough to precipitate
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Does it work?
Yeah, was hard to prove for a long time but the SNOWIE project used high resolution radar to measure increased precipitation exclusively in the track of their seeding plane
Each of those lines is millions of gallons of snowmelt!
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Types of cloud seeding: Hygroscopic
This involves dispersing small volumes of minerals (often table salt) into clouds to attract small water droplets into heavier ones
It's often used in hotter regions of the globe (i.e. UAE, Philippines)
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Types of cloud seeding: Glaciogenic
This involves dispersing small volumes (~1kg/100,000km^2) of minerals that freeze small water droplets into snowflakes large enough to fall
Silver Iodide (AgI) has been used for decades and has a crystal structure like ice
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Wait, people have been cloud seeding for decades?
Yes! The technology was invented in the United States in 1946
We used to have large programs, China now spends $100Ms more than us per year (~$300M)
Here's a map of all the active programs in the US and abroad
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Is AgI from cloud seeding safe?
Yup, 78 years of data have shown no impacts on environmental or human health in seeded regions
The US drinking water threshold for safe AgI levels is 100mg/L
To be safe, the most sensitive algae are harmed at 1.4mg/L, so let's go w that
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AgI doesn't bioaccumulate
In an area downstream of a multiyear seeding campaign, the Salt Springs Reservoir in CA, AgI concentrations were measured at <0.0005 µg/L
This is well within naturally occurring levels. Decades of seeding in Nevada has increased concentrations by parts per trillion in soil, and silver is naturally occurring in PPM
so chronic exposure and build up is not a concern
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AgI is also quite safe itself!
I don't endorse eating it ofc
But, if you were to eat AgI, it's 14x less toxic than aspirin (LD50 of 2820mg/kg vs 200mg/kg)
And AgI is insoluble in water and fat, so an adult would need to eat ~0.4lbs in one sitting for a toxic dose
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"You're stealing rain from other people!"
Nope! The body of evidence from decades of American universities is seeding is positive sum
Only ~9% of atmospheric water precipitates, and seeding precipitates ~1% more of the non-precipitating ice/liquid
34 years of data from Utah show mild increases in precipitation downwind!
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"You're going to block out the sun to cool the planet!"
No, that's solar radiation management (SRM): emitting reflective aerosols into the stratosphere
Cloud seeding and SRM are different, here's my testimony to the TN legislature on the difference 11/
How many nuclear bombs would it take to build a mountain in Kansas?
When people discuss terraforming or geoengineering, they're usually referring to atmospheric interventions – but what would it take to create new earthen formations?
Can we engineer geography?
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I'm not the first to think of terraforming w nukes
In the 60s the United States had Project Plowshare: an initiative to investigate using nuclear explosives for construction purposes
There was a proposal to build a new deep water harbor in Alaska with 5 hydrogen bombs
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The USSR had the Nuclear Explosions for the National Economy program
A fine example of their work is Atomic Lake, also known as Lake Chagan
They built this beautiful reservoir with a single 140 kiloton bomb
Full of fish too
Future 🧵how many nukes to end water scarcity? 🤔 3/