Weather modification is the act of intentionally manipulating or altering the weather. The most common form of weather modification is cloud seeding to increase rain or snow, usually for the purpose of increasing the local water supply. Weather modification can also have the goal of preventing damaging weather, such as hail or hurricanes, from occurring; or of provoking damaging weather against an enemy or rival, as a tactic of military or economic warfare. Weather modification in warfare has been banned by the United Nations.
Magical and religious practices to control the weather are attested in a variety of cultures. In ancient India it is said that yajna or vedic rituals of chanting manthras and offering were performed by rishis to bring sudden bursts of rain fall in rain starved regions. Some American Indians like some Europeans had rituals which they believed could induce rain. The Finnish people, on the other hand, were believed by others to be able to control weather. As a result, Vikings refused to take Finns on their oceangoing raids. Remnants of this superstition lasted into the twentieth century, with some ship crews being reluctant to accept Finnish sailors. The early modern era saw people observe that during battles the firing of cannons and other firearms often initiated precipitation. In Greek mythology, Iphigenia was offered as a human sacrifice to appease the wrath of the goddess Artemis, who had becalmed the Achaean fleet at Aulis at the beginning of the Trojan War. In Homer's Odyssey, Aeolus, keeper of the winds, bestowed Odysseus and his crew with a gift of the four winds in a bag. However, the sailors opened the bag while Odysseus slept, looking for booty, and as a result were blown off course by the resulting gale. In ancient Rome, the lapis manalis was a sacred stone kept outside the walls of Rome in a temple of Mars. When Rome suffered from drought, the stone was dragged into the city. The Berwick witches of Scotland were found guilty of using black magic to summon storms to murder King James VI of Scotland by seeking to sink the ship upon which he travelled. Scandinavian witches allegedly claimed to sell the wind in bags or magically confined into wooden staves; they sold the bags to seamen who could release them when becalmed. In various towns of Navarre, prayers petitioned Saint Peter to grant rain in time of drought. If the rain was not forthcoming, the statue of St Peter was removed from the church and tossed into a river.
Dr Walter Russell wrote of weather control in Atomic Suicide 1956."--give him complete power to cause rains, wherever he desires, on deserts or meadows and to dissipate cyclones while forming."page xxvii
In January, 2011, several newspapers and magazines, including the UK's Sunday Times and Arabian Business, reported that scientists backed by the government of Abu Dhabi, the capital of the United Arab Emirates, had created over 50 artificial rainstorms between July and August 2010 near Al Ain, a city which lies close to the country's border with Oman and is the second-largest city in the Abu Dhabi Emirate. The artificial rainstorms were said to have sometimes caused hail, gales and thunderstorms, baffling local residents. The scientists reportedly used ionizers to create the rainstorms, and although the results are disputed, the large number of times it is recorded to have rained right after the ionizers were switched on during a usually dry season is encouraging to those who support the experiment.
Cloud seeding 
Cloud seeding is a common technique to enhance precipitation. Evidence on its safety is strong, but there are still doubts about its effectiveness. Cloud seeding entails spraying small particles, such as aluminium oxide, barium, (like silver iodide) onto clouds in order to affect their development, usually with the goal of increasing precipitation. Cloud seeding only works to the extent that there is already water vapor present in the air. Critics generally contend that claimed successes occur in conditions which were going to lead to rain anyway. It is used in a variety of drought-prone countries, including the United States, the People's Republic of China, India, and Russia. In the People's Republic of China there is a perceived dependency upon it in dry regions, and there is a strong suspicion it is used to "wash the air" in dry and heavily polluted places, such as Beijing. In mountainous areas of the United States such as the Rocky Mountains and Sierra Nevada, cloud seeding has been employed since the 1950s.
Storm prevention 
Project Stormfury was an attempt to weaken tropical cyclones by flying aircraft into storms and seeding the eyewall with silver iodide. The project was run by the United States Government from 1962 to 1983. A similar project using soot was run in 1958, with inconclusive results. Various methods have been proposed to reduce the harmful effects of hurricanes. Moshe Alamaro of the Massachusetts Institute of Technology proposed using barges with upward-pointing jet engines to trigger smaller storms to disrupt the progress of an incoming hurricane; critics doubt the jets would be powerful enough to make any noticeable difference.
Alexandre Chorin of the University of California, Berkeley, proposed dropping large amounts of environmentally friendly oils on the sea surface to prevent droplet formation. Experiments by Kerry Emanuel of MIT in 2002 suggested that hurricane-force winds would disrupt the oil slick, making it ineffective. Other scientists disputed the factual basis of the theoretical mechanism assumed by this approach. The Florida company Dyn-O-Mat proposes the use of a product it has developed, called Dyn-O-Gel, to reduce the strength of hurricanes. The substance is a polymer in powder form which reportedly has the ability to absorb 1,500 times its own weight in water. The theory is that the polymer is dropped into clouds to remove their moisture and force the storm to use more energy to move the heavier water drops, thus helping to dissipate the storm. When the gel reaches the ocean surface, it is reportedly dissolved. The company has tested the substance on a thunderstorm, but there has not been any scientific consensus established as to its effectiveness.
Hail cannons have been used by some farmers since the 19th century in an attempt to ward off hail, but there is no reliable scientific evidence to confirm their effectiveness. Another new anti-hurricane technology is a method for the reduction of tropical cyclones’ destructive force - pumping sea water into and diffusing it in the wind at the bottom of such tropical cyclone in its eyewall.
Hurricane modification 
- Using lasers to discharge lightning in storms which are likely to become hurricanes
- Pouring liquid nitrogen onto the sea to deprive the hurricane of heat energy.
- Creating soot to absorb sunlight and change air temperature and hence convection currents in the outer wall.
Weather modification and law 
US and Canada agreement 
In 1975, the US and Canada entered into an agreement under the auspices of the United Nations for the exchange of information on weather modification activity.
1977 UN Environmental Modification Convention 
Weather modification, particularly hostile weather warfare, was addressed by the "United Nations General Assembly Resolution 31/72, TIAS 9614 Convention on the Prohibition of Military or Any Other Hostile Use of Environmental Modification Techniques." The Convention was signed in Geneva on May 18, 1977; entered into force on October 5, 1978; ratified by U.S. President Jimmy Carter on December 13, 1979; and the U.S. ratification deposited at New York January 17, 1980.
US National Oceanic and Atmospheric Administration 
In the US, the National Oceanic and Atmospheric Administration keeps records of weather modification projects on behalf of the Secretary of Commerce, under authority of Public Law 92-205, 15 USC § 330B, enacted in 1971.
Proposed US Legislation 
2005 U.S. Senate Bill 517 and U.S. House Bill 2995 U.S. Senate Bill 517 and U.S. House Bill 2995 were two bills proposed in 2005 that would have expanded experimental weather modification, to establish a Weather Modification Operations and Research Board, and implemented a national weather modification policy. Neither were made into law. Former Texas State Senator John N. Leedom was the key lobbyist on behalf of the weather modification bills.
2007 U.S. Senate Bill 1807 & U.S. House Bill 3445 Senate Bill 1807 and House Bill 3445, identical bills introduced July 17, 2007, proposed to establish a Weather Mitigation Advisory and Research Board to fund weather modification research 
Future aspirations 
Climatologists have simulated hurricane control based on selective heating and cooling (or prevention of evaporation). Futurist John Smart has discussed the potential for weather control via space-based solar power networks. One proposal involves the gentle heating via microwave of portions of large hurricanes. Such chaotic systems may be susceptible to "side steering" with a few degrees of increased temperature/pressure at critical points. A sufficient network might keep the largest and most potentially damaging hurricanes from landfall, at the request of host nations. Blizzards, monsoons, and other extreme weather are also potential candidates for space-based amelioration. If large-scale weather control were to become feasible, potential negative implications may include:
- Unintended side effects, especially given the chaotic nature of weather development
- Damage to existing ecosystems
- Health risks to humans
- Equipment malfunction or accidents
- Malevolent control or use as a weapon
- ELF hot spots causing slightly accelerated ionospheric depletion by solar wind [not in citation given]
For the 2008 Olympics, China had 30 airplanes, 4,000 rocket launchers, and 7,000 anti-aircraft guns to stop rain. Each system would shoot various chemicals into any threatening clouds to shrink rain drops before they reach the stadium.
See also 
- Weather Modification Operations and Research Board
- Global warming
- Weather forecasting
- Hail cannon
- Operation Popeye
- Beijing Weather Modification Office
- Project Cumulus
- Alberta Hail Project
- Chemtrail conspiracy theory
- Fog Investigation and Dispersal Operation (FIDO)
- Gelt, Joe. "Weather Modification: A Water Resource Strategy to be Researched, Tested Before Tried". University of Arizona. Retrieved April 17, 2012.
- Homer, The Odyssey, book 10.
- Sir James Frazer, The Golden Bough, ch. 5 (abridged edition), "The Magical Control of Rain"
- Christopher Smout, A History of the Scottish People 1560-1830, pp. 184-192
- Adam of Bremen and Ole Worm are quoted as maintaining this in Grillot de Givry's Witchcraft, Magic and Alchemy (Frederick Publications, 1954).
- Frazer, supra.
- Leigh, Karen. , "Arabian Business", January 3, 2011. Retrieved 2011-01-8.
- , "Daily Mail", January 3, 2011. Retrieved 2011-01-8.
- Hunter, Steven M. (U.S. Bureau of Reclamation). 2007. Optimizing Cloud Seeding for Water and Energy in California. California Energy Commission, PIER Energy‐Related Environmental Research Program. CEC‐500‐2007‐008. http://www.energy.ca.gov/2007publications/CEC-500-2007-008/CEC-500-2007-008.PDF
- http://environment.newscientist.com/article/dn7995.html - Alamaro proposal and energy critique
- "Moshe Alamaro's brief bio". Alamaro.home.comcast.net. Retrieved 2011-06-04.
- "Chorin proposal". Newscientist.com. Retrieved 2011-06-04.
- "Kerry Emanuel's Homepage". Wind.mit.edu. 2002-05-15. Retrieved 2011-06-04.
- "Could humans tackle hurricanes? - earth - 14 September 2005 - New Scientist Environment". Environment.newscientist.com. Retrieved 2011-06-04.
- "Oil on troubled waters may stop hurricanes - earth - 25 July 2005". New Scientist. Retrieved 2011-06-04.
- Anti-hurricane invention worth pursuing. Murdock, Deroy. Scripps Howard News Service. 22 Oct 2005.
- WIPO. "(WO/2006/085830) A METHOD OF AND A DEVICE FOR THE REDUCTION OF TROPICAL CYCLONES DESTRUCTIVE FORCE". Wipo.int. Retrieved 2011-06-04.
- . CBC http://cogentbenger.com/documentaries/how-to-stop-a-hurricane/. Retrieved 2012-11-19. Missing or empty
- "Agreement Relating to the Exchange of Information on Weather Modification Activities" (PDF). Retrieved 2011-06-04.
- "Environmental Modification Convention". Fas.org. Retrieved 2011-06-04.
- "Convention on the Prohibition of Military or Any Other Hostile Use of Environmental Modification Techniques". United States Department of State. Archived from the original on 2007-09-14. Retrieved 2007-09-28.
- "15 USC CHAPTER 9A - WEATHER MODIFICATION ACTIVITIES OR ATTEMPTS; REPORTING REQUIREMENT". Retrieved April 18, 2012.
- S. 517 [109th]: Weather Modification Research and Development Policy Authorization Act of 2005, proposed by U.S. Senator Kay Bailey Hutchison of Texas and then U.S. Representative (later Senator) Mark Udall of Colorado (GovTrack.us)
- "H.R. 2995 [109th]: Weather Modification Research and Technology Transfer Authorization Act of 2005". GovTrack.us. Retrieved 2011-06-04.
- [dead link]
- "S. 1807 [110th]: Weather Mitigation Research and Development Policy Authorization Act of 2007". GovTrack.us. Retrieved 2011-06-04.
- Hoffman, R, "Controlling Hurricanes," Scientific American, Oct 2004.
- Kevin J. Zahnle, "Our Planet's Leaky Atmosphere," Scientific American, May 2009.
- Demick, Barbara, "China plans to halt rain for Olympics," Los Angeles Times, January 2008.
- Weather Modification Association Perhaps the largest commercial overhead organization for weather modification research and application.
- The Testimony of Dr. Tom DeFelice (Past President, Weather Modification Association) in support of Weather Modification Operations and Research Board
- 109th Congress S. 517: Weather Modification Research and Technology Transfer Authorization Act of 2005
- Article Montana restricts spraying to a window of months and requires materials and employee lists
- "The Weather Modification Operations and Research Board (passed Oct.2005) - in corporate cooperation with BAE Systems (HAARP apparatus & facility owner) and Raytheon Corporation (HAARP patent owner)
- "NOAA’S National Weather Service Awards $300 Million AWIPS Contract to Raytheon"
- North American Interstate Weather Modification Council
- The Gateway Arch as a weather control device
- Scientific American Magazine (October 2004 Issue) Controlling Hurricanes
- That's Impossible: Weather Warfare, History Channel
- Process for weather control, H. M. Brandau, U.S. Patent 2,756,097
- Weather control by artificial means, Heinz W. Kasemir, U.S. Patent 3,284,005
- Cloud formation and subsequent moisture precipitation, U.S. Patent 3,409,220
- System and method for irradiation of planet surface areas, Arthur G. Buckingham, U.S. Patent 3,564,253
- Weather modification method, Knollenberg, U.S. Patent 3,613,992
- Combustible compositions for generating aerosols, particularly suitable for cloud modification and weather control and aerosolization process, Consiglio Nazionale delle Ricerche, U.S. Patent 3,630,950
- Method and apparatus for altering a region in the Earth's atmosphere, ionosphere, and/or magnetosphere, J. Eastlund[who?], U.S. Patent 4,686,605
- Method and composition for precipitation of atmospheric water, Slavko Mentus, U.S. Patent 5,360,162
- Use of artificial satellites in earth orbits adaptively to modify the effect that solar radiation would otherwise have on earth's weather, Franklin Y. K. Chen, U.S. Patent 5,762,298
- Weather modification by artificial satellites, Franklin Y. K. Chen, U.S. Patent 5,984,239
- Method of and a device for the reduction of tropical cyclones destructive force, Jozef Solc, U.S. Patent 7,798,419
- Combustible compositions for generating aerosols, particularly suitable for cloud modification and weather control and aerosolization process, Consiglio Nazionale delle Richerche, U.S. Patent RE29,142