Not thought through
I guess they didn't read the bit in their Dummies Guide to Climate Engineering about water actually being a greenhouse gas, so if you're increasing the amount of water vapour at lower altitudes, some will be forced up to higher altitudes where its less humid simply by natural equilibriums, and at these higher altitudes it will keep more heat inside the atmosphere.
Then there's the weather influences these actions will have, the most obvious detrimental effect would be flooding, perhaps even flash floods, and the legal repercussions of this once the damage is determined to be from a cloud formed by these machines. There's also the question of how much impact this will have on regional and global climate processes over the short term, will it affect crop growing seasons, will the increased cloud cause rain to fall before it reaches areas it used to reach, thus creating new arid regions.
IMO this seems as badly thought out as the idea several years ago of just dumping millions of tons of iron dust into the oceans to encourage algal blooms (consuming CO2, but using up nutrients and killing whole areas of the ocean ecosystem). Natural systems operate in a fine balance, they can counteract or stabilise changes over a long period (hence past climate change), but its far better for us to reduce our impact on the climate than to try and tinker with these systems even more in the hope that we fix something, and can carry on polluting without a care.
Biting the hand that feeds IT
