Hammond.Fischer+MMA+Spring+2010+Energy+and+Water+wiki

= = Cloud Seeding

**By: Alex Hammond and Ryan Fischer**

Ancient Weather Changes
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 * Present Weather Changes**



Intro
Human beings have been trying to control the weather for hundreds of years. Many ancient cultures had rituals that they hoped would change the weather. The best example is the native american rain dance. Now a days scientists are able to release chemicals into clouds controlling the precipitation. The chemicals are usually released from planes or missiles launched into the air. A primitive version of this technique is when trees release a chemical called Terpenes into the atmosphere. Cloud seeding is mainly used to create rain fall during droughts, but it can also be used to controlling temperature, suppressing fog and cloud coverage. Low lying clouds are able to shield the earth from excess sunlight. Cloud seeding could be the answer to the fresh water shortage and climate change.

The Water Shortage


Due to climate change the earth's fresh water supplies are shrinking fast.The rising global temperature is the main cause of the water shortage. The climate change is changing rich farmland into areas where only the heartiest crops could survive. If the global temperature continues to rise many areas will experience droughts and water shortages. A study was done on rice, it was found that every time the temperature rose by 1 degree Celsius the rice produced will fall 10%. Rice is the main food for more than half the world. All crops would be affected by drought and in many third world country's their entire lively-hood is based on agriculture.Glaciers and the polar ice caps are melting and combining with salt water. Many rivers can be traced back to glaciers located around the world. Ice makes up 70% of the world's fresh water. Experts predict that there will be no ice in the north pole as early as five years from now. Drought and a rising sea level will also affect the amount of drinking water. It is estimated that in 2025 that 63% of the world's population will have trouble finding fresh water. Scientists all over the world are trying to solve the global water crisis. They have come up with many new inventions, cloud seedings is just one of many. New sanitation devices make safe drinking water available to people in third world countries. Wastewater treatment is becoming common in many developed countries. This takes sewage or stagnant water and removes all of the impurities, making it safe for human use. Water desalination follows the same process except it starts with salt water and removes all the impurities. If nothing is done about the water crisis, it has the potential to be greatest disaster humanity has ever faced.

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Cloud seeding starts by releasing salt or silver iodide into an existing cloud. The chemicals can be released from airplanes above the clouds or can be launched into the clouds from below.If the chemical that was released was silver iodide, it causes the moisture in the clouds to freeze. This happens because Silver iodide has a crystalline structure very similar to ice. When the water vapors freeze they become heavy enough to fall as snow or rain. This type of cloud seeding is called Static Cloud Seeding. Another type of cloud seeding that uses chemicals is Hygroscopic Cloud Seeding. This process uses salt to gather the moisture in the surrounding atmosphere into droplets. Once the droplets become large enough they fall to the ground. This technique is still experimental, but it holds the most potential. Dynamic Cloud Seeding is the hardest to implement. It does not use chemicals, instead it requires many different steps. It makes use of the vertical motion of hot air. Dynamic Cloud Seeding is the riskiest of all three types of cloud seeding, but it can be the most rewarding. All three types of cloud seedings increase the amount of precipitation in the immediate atmosphere causing an increase in rainfall or in some cases it will cause it to start raining.

Water Generation


Cloud seeding produced almost 13 billion gallons of extra rain fall in Nevada in six months. Some scientists say that this is only a 5% increase in rain fall, while others put it closer to 15%. Cloud seeding is suited for long term production. Studies have shown that if used over a longer period of time cloud seeding can produce 25% to 42% extra rain fall.


 * Increases the freshwater supply by increasing rain fall.
 * If used correctly it can increase the average rainfall by 25% to 42%.
 * Can help prevent major storm systems from forming.
 * Reduces the size of hailstones caused by thunderstorms.
 * Stops fog from forming near airports and other transportation hubs.
 * Can prevent snowfall, producing a mild winter.
 * Increases the areas that can be farmed and the length of the farming season.
 * Can help prevent global warming by reflecting excess UV rays off of low lying clouds.

Cloud seeding is still a work in progress. Scientists understand the basics of cloud seeding, but they still have to improve it to make it practicable. It is hard to work with something as unpredictable as the weather. Many countries have claim to have proven cloud seeding, but because of this unpredictability skeptics still exist. A major area of concern for critics are the chemicals released into the clouds. Silver iodide is a hazardous material and is harmful to most lifeforms. They are also weary of the chemical trials left behind in the atmosphere. They believe that these will have a lasting affect on the atmosphere. At the moment cloud seeding is to expensive to be a legitimate solution to the water crisis. Since cloud seeding is a relatively new technology, there is a lot of uncertainty surrounding the long term effects of cloud seeding. This is perhaps the greatest are of concern for skeptics.

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Cloud seeding can solve the water crisis by making fresh water more available worldwide. With an increase in rainfall, farmers would not have to worry about droughts. More fresh water would mean drinking water is available in many countries. If cloud seeding was used to create low lying clouds over the ocean, it would reflect excess sunlight. This would help lower the global temperature and the water supply would become stable.

Cloud Seeding Around the World
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Over twenty countries worldwide have active cloud seeding programs. Cloud seeding can be found in eleven states, Canada, China, Australia, India and Russia. China used claims to prevent rainstorms during the 2008 Olympic opening ceremony using Cloud Seeding. Australia is having mixed results, they have found that cloud seeding is more effective in different areas. USA uses it to increase rainfall during droughts and prevent fog from forming around airports. Russia promised citizens that they will have a "winter without snow" because of cloud seeding. In 1978 many countries in the UN signed a treaty banning weather modification during international warfare. Many private companies use cloud seeding. Some ski resorts have been known to use cloud seeding to increase their annual snowfall. Farmers sometimes hire airplanes to release chemicals into clouds above their crops. Cloud seeding is used worldwide both in the public and private sector.

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Cloud seeding is still a new technology and has to be researched further before it becomes available all over worldwide. Cloud seeding is still in an experimental phase, scientists are trying to make it more efficient. They also have to make it more predictable because now it all depends on the local weather which is unpredictable. There is also much concern about the long term effects of releasing chemicals into the atmosphere, but no information has been obtained to prove that it is harmful to the environment. Policy-makers have to convince the general public that cloud seeding is not dangerous and has incredible potential. Other scientists are drawing plans for a fleet of unmanned boats that would follow the wind around ocean releasing chemicals that would be used for cloud seeding. Cloud seeding is full of potential, but in order for it to be used on the larger scale more research has to be done.

At this point in time Cloud seeding cannot solve the water crisis, but it has the potential to. Cloud seeding is to expensive and wasteful to be used globally. Cloud seeding needs to be researched more, we need to know all of the risks surrounding it. Once research is done, it should be used in third world countries because they are the most effective by the water shortage. In the future fleets of unmanned boats could travel around the oceans releasing chemicals into the air. This would be an inexpensive and effective way to combat the water crisis.