Cloud seeding to enhance precipitation (unproven at decision-relevant scale)
#00202
Silver-iodide or hygroscopic seeding of clouds to increase rain or snow. Politically attractive, but the US GAO found estimated effects often statistically indistinguishable from zero, and no drought-scale water yield has been demonstrated anywhere.
Utah, USA
InconclusiveUtah Division of Water Resources with contracted seeding operators · Region
Utah has run a statewide winter cloud seeding program since the 1970s, operated by the Utah Division of Water Resources with contracted seeding operators, and expanded funding substantially in 2023 amid Colorado River s…
Claimed precipitation increaseUnverified per GAO → 5–15% (program claim)% precipitation
GAO finding on statistical significance of program effectsOften statistically indistinguishable from zero
State of Utah, with expanded appropriations in 2023