system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: China creates 55 billion tons of artificial rain a year using cloud seeding. Why can't California use the same technology to combat droughts?
gpt
Artificial rain is just water that's forced to fall out of the sky as rain by some chemical. So a plane will "seed" a cloud with this chemical, and the chemical reacts with the water in the cloud to make it form drops and fall.

It doesn't actually create any new water moisture though. So in California's case, where it's not just a lack of rain, but a lack of moisture in the atmosphere, seeding the clouds wouldn't help because there wouldn't be very much rain to seed in the first place.