EcoHearth: Come Home to the Earth

Does cloud seeding help or harm the environment? While Moscow’s mayor has promised a snow-free winter this year, others fear there may be unintended environmental side-effects from firing silver iodide and other substances into clouds. Even if cloud seeding proves harmless, can humans be trusted to decide where the rain, snow, fog or hail should fall without upsetting nature’s fine balance, as well as each other?

The Uses of Cloud Seeding
Since its invention in 1946, cloud seeding has entered the history books: Americans seeded clouds to extend the monsoon over the Ho Chi Minh Trail from 1967 to 1972 during the Vietnam War, and Russians seeded clouds over Belarus in 1986 to stop radioactive particles reaching Moscow after the Chernobyl nuclear disaster.

The potential for weather warfare has led to 75 countries signing the United Nation’s Environmental Modification Convention since its launch on October 5, 1978 under the name of the ‘Convention on the Prohibition of Military or any other Hostile Use of Environmental Modification’ (ENMOD). While this allows citizens to use weather modification for peaceful purposes, most countries enforce strict licenses and rules for anyone wishing to do so.

China operates the world’s largest cloud-seeding system. It has used the process to prevent rain during Beijing’s 2008 Olympic Games and a 2009 parade celebrating 60 years of communist party rule. Common sponsors of global cloud-seeding projects today include water agencies, municipalities, airports and recreational areas such as ski resorts.

The potential benefits of being able to control the weather are endless: reducing flooding and drought, extinguishing brushfires and creating favorable conditions for ships and planes, to name a few. Many areas of the world have ongoing weather-modification programs, including 11 western states in the US, Alberta province in Canada and Tasmania province in Australia.

How Cloud Seeding Works
Cloud seeding can be carried out from the ground or air, and the materials used fall into two categories: ice-forming (glaciogenic) and water-attracting (hygroscopic). Silver iodine (AgI), dry ice, compressed liquid propane and carbon dioxide are all ice-forming materials, while water-attracting materials include salt, urea and ammonium nitrate.

There are also two cloud-seeding processes: cold and warm. Cold cloud seeding uses ice-forming materials to freeze super-cooled water droplets within a cloud, while warm cloud seeding uses water-attracting materials to cause droplets to condense within a cloud (droplets condense when they collide).

Environmental Dangers
While intense exposure to silver iodide (the most common seeding material) can cause temporary incapacitation in humans and mammals, the concentration used in cloud seeding is 100 times less than individual tooth fillings, normally only 0.1 micrograms per liter of water, which is well below the 50 microgram limit set for drinking water by the US Public Health Service. Australia originally banned cloud seeding for fear of endangering the protected pygmy possum, but as silver iodide is used instead of pure silver, the Weather Modification Association disputed such fears by drawing the following conclusion from peer-reviewed research:

“Environmental impact studies related to silver iodide usage in cloud seeding were conducted starting in the 1960s and continue to be conducted today; all findings to date indicate no adverse environmental and human health impacts.”

Cloud-Seeding Accidents
The life-changing impact of weather modification provides the potential for serious accidents. One such example is the Operation Cumulus project, carried out by the British Royal Air Force and Western scientists during the period of August 4-15, 1953, which led to 35 flood-related deaths in Devon.

A more recent, smaller-scale mishap occurred in June 2008, when the Russian Air Force tried seeding clouds over Moscow using bags of cement; one crashed through a roof after failing to turn to powder.

Water Wars
Weather-modification techniques will become more highly sought after in the future due to the effects of global warming, as two-thirds of the world will be suffering from water shortages by 2025, according to the South African Weather Service. It is predicted that Yemen will be the first country in the world to run out of water—in as little as 10 years time, or less if its population continues to grow.

While weather control will always be in demand for recreational purposes, such as forcing a black cloud to rain before it reaches your garden party, the obvious way to reduce the need for drought relief is to tackle the root cause: global warming. After that, unless anyone secures enough evidence of harmful environmental effects, weather control offers the potential to combat extreme weather conditions across the globe. Let’s just hope neighboring areas won’t accuse each other of stealing their rain, otherwise a seeming solution to our water woes may spur the unintended and deadly consequence of water wars.

Additional resources:
World Weather Research Programme (WWRP)
Weather Enhancement Technologies (WET) International

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