Last month Dubai was hit by an epic storm when a year’s rain fell in one day. Conspiracy theorists blamed the UAE’s cloud-seeding programme, which for years has launched flares into warm cumuliform clouds, releasing compounds to act as seeds for droplet formation.
This seeding is supposed to produce more frequent and heavier rain than the clouds would otherwise release, but the effect is small. As with drugs that only helps a small percentage of patients, it is impossible to compare the result with what would have happened anyway, and a large number of tests are needed. Enthusiasts and sceptics have argued about cloud-seeding statistics for decades.
There is no evidence the Dubai storm was artificially caused, but it highlights the legal aspects of such work. A 1972 flood in South Dakota triggered a lawsuit against the US government because it happened on the same day as a cloud-seeding experiment. The suit was finally dismissed, but the legal situation was never fully resolved.
More topically, in 1977 the attorney general of Idaho accused neighbouring Washington of “cloud rustling” by extracting rainfall. Iran made similar accusations against Israel last year. In a world of water shortages, cloud seeding, whether or not it works, may increasingly be a focus for international disputes.
