Yup, humans have been messing with Mother Nature as soon as they stood upright. One of the newer techniques for messing with the Earth is known as Cloud Seeding.

It's a pretty simple concept, dump material in to a cloud which encourages it to form ice crystals. Those ice crystals, once there are enough of them, will turn to rain. Bam! you've just solved a drought!

Or does it really work that way?