Unfortunately, the internet contains many misleading ideas about cloud-seeding. Below is a series of misconceptions and questions about the common scientific practice.
FAQ:
1. Is cloud-seeding producing so-called “chem-trails”?
No. Those fluffy white lines zig-zagging across the sky are jet contrails, and they are the aviation equivalent of visible plumes of steamy breath on a cold morning. Warm water vapor produced during jet fuel combustion interacts with the cold atmospheric air to create strings of ice crystals that behave like high-altitude cirrus clouds. When a plane passes through an area of high pressure, which leads to low winds and clear skies, the trails will linger. Jet contrails have no connection with cloud-seeding activities.
2. Is cloud-seeding “geoengineering”?
Cloud-seeding is a well-researched and monitored form of small-scale weather modification. Other examples of ways that humans change the weather and the global climate include: driving a car, deforestation, and air pollution from industry.
3. Who is funding cloud-seeding programs?
Cloud-seeding programs occur worldwide. In the Western U.S., state and agency-supported efforts occur across California, Nevada, Colorado, New Mexico, Wyoming, Kansas, Oklahoma, Texas, North Dakota, Utah, and Idaho.
4. Is silver iodide toxic?
No. The silver used in cloud-seeding is silver iodide (AgI, or silver bonded to iodine), which can be confused with other molecular forms of silver. When silver is isolated as an ion (Ag+) it is biologically active, meaning it interacts with bacterial or fungal cell walls — which is why it’s often used for medicinal purposes and for sterilizing drinking water. Silver ion (Ag+) can be hazardous in aquatic environments because it can also interact with proteins and other parts of cell membranes, but silver iodide (AgI), not silver ion (Ag+), is used for seeding clouds. Silver iodide retains its form in water and does not break down into the potentially toxic silver ion. When the silver iodide particle falls to the ground with rain or snow, it separates from the water molecules that formed an ice crystal around it, essentially becoming a speck of dust no different from the silver naturally occurring in the soil.
Although the chemistry can be a bit complicated, you can think of it as the difference between water (H2O) – the life-giving force that forms much of your own body – and hydrogen peroxide (H2O2), which is used as a sterilizer and bleaching agent and is hazardous at high concentrations .
5. Is cloud-seeding used for military purposes?
Following the (now declassified) use of cloud-seeding by the U.S. military during the Vietnam War, a 1977 international treaty banned the use of weather modification in warfare.
6. Does DRI continue cloud-seeding during intense winters like the winter of 2022-2023?
DRI pauses all cloud-seeding activities when the snowpack reaches 150% of the historical average. In the Lake Tahoe region, this means that cloud-seeding activities halted in mid-December, 2022, due to the remarkable amount of natural snowfall occurring.
More information:
The Cloud Seeders
A short video about DRI’s cloud-seeding team
Where to find more water: eight unconventional resources to tap
The Conversation
By Manzoor Qadir and Vladimir Smakhtin, Deputy Director and Director of the United Nations Institute for Water, Environment, and Health
Can cloud seeding help quench the thirst of the U.S. West?
Yale e360
Wintertime Orographic Cloud Seeding—A Review
Journal of Applied Meteorology and Climatology, Vol. 58, No. 10 (October 2019), pp. 2117-2140
Quantifying snowfall from orographic cloud-seeding
PNAS, Vol. 117, No. 10 (February 2020), pp. 5190-5195
Does cloud seeding really work? An experiment above Idaho suggests humans can turbocharge snowfall
Science Magazine
