Cloud Seeding Explained: What It Is, What They Use, and Why It Matters

What Is Cloud Seeding?

Cloud seeding is the deliberate introduction of substances into clouds to alter precipitation patterns. It has been practiced since the 1940s and is currently active in over 50 countries worldwide, including extensive programs across the western United States, China, and the UAE.

How It Works

The most common method involves dispersing silver iodide (AgI) particles into clouds. Silver iodide has a crystal structure similar to ice, which causes supercooled water droplets in clouds to freeze around these particles and fall as precipitation.

There are two primary delivery methods:

• Ground-based generators that burn acetone-silver iodide solutions, sending smoke plumes into passing cloud systems
• Aircraft-mounted flare systems that release AgI smoke directly into cloud formations at altitude

What Chemicals Are Used?

The primary chemicals involved in cloud seeding include:

• Silver iodide (AgI) — the main seeding agent
• Acetone — used as a carrier solvent for silver iodide
• Liquid propane — used in some ground-based systems
• Dry ice (solid CO2) — an alternative seeding agent
• Hygroscopic salts — used in warm cloud seeding

The Cumulative Problem

While individual seeding events deposit small amounts of silver iodide, the cumulative effect of decades of continuous operations has never been comprehensively studied. Silver ions are toxic to aquatic organisms, and bioaccumulation means levels increase over time in fish, plants, and the water supply.

What You Can Do

Stay informed, share this information, and support legal efforts to require transparency and environmental review for all atmospheric modification programs.