Cloud seeding is a form of weather modification. The goal of this work is to change the amount of precipitation that falls from the sky or to alter the type that would reach the ground. It occurs when substances are dispersed into the air that serve as ice nuclei or condensation.
Most efforts at cloud seeding try to increase the levels of precipitation that fall, providing more rain or snow resources to fight drought or other low-moisture conditions. Hail suppression and fog management are additional forms of this activity that you can see happening at airports when challenging weather conditions exist.
Silver iodide, dry ice, and potassium iodide are the most common items used to initiate the cloud seeding process. Liquid propane is also an option used in some situations because it forms ice crystals at a higher temperature. Dispersal occurs through aircraft release.
There are several advantages and disadvantages of cloud seeding to consider before initiating this practice locally.
List of the Advantages of Cloud Seeding
1. There are three primary methods of cloud seeding that we can use.
Cloud seeding offers some flexibility because there are three different methods that have shown to be effective at least partially. Static seeding involves spreading silver iodide into the clouds to provide crystals around which moisture condenses. That makes the cloud more effective at dispersing water.
Dynamic cloud seeding tries to boost vertical air currents. This process is more complex than the static model because it encourages more moisture to pass through the clouds. Then Hygroscopic seeding disperses salts through explosives or flares in the lower portion of a cloud. As the water joins with them, they grow in size to contribute more precipitation.
2. The efforts at cloud seeding can help to produce more precipitation.
Cloud seeding attempts to create more precipitation because of the need to have more condensation fall to the ground. When the conditions are right for rain but the clouds are not strong enough to produce it, this work can make a positive impact on the regions of our world that see consistent drought problems. This technique helps agricultural workers produce more crops of better quality. It allows groundwater ecosystems to recharge. When we are effective at this technology’s distribution, it begins to reduce the risks of famine on our planet.
3. Cloud seeding can make the land more suitable for living.
We have regions of our planet that are difficult for human survival because there is a lack of moisture present. Although we don’t want to turn every desert green, the work of cloud seeding creates the potential for more precipitation. If we use this method along mountain ranges where the snowpack serves as the water supply for local communities, then it is possible to make more land suitable for living because we have additional resources available to use consistently.
4. This work helps to regulate weather patterns in specific locations.
Airports frequently use cloud seeding as a way to create consistent conditions around their runways. When fog, hail, or ice are present, then the impacts on the aircraft can limit the ability to take off or land. The processes used in this situation help to transform the precipitation or change its visual impact for pilots so that passenger travel becomes safer.
This adaptation of local weather conditions can work in reverse when there are specific conditions present in the sky. Seeding clouds that are already primed to provide rain or snow allows us to maximize the impact of an upcoming precipitation event.
5. Economic improvements occur because of cloud seeding.
There are several economic benefits to think about when looking at the advantages and disadvantages of cloud seeding. If farmers can improve their crop quality and yield, then they will make more money to support their families. Tourism improves when there are more recreational waters and snowy slopes to use. Additional resources create new jobs that boost wages and spending in communities so that new support businesses (like restaurants, grocery stores, or entertainment destinations) can begin.
Cloud seeding offers opportunities to limit famine, reduce drought, and create better freshwater resources. Each is an economic opportunity that can improve the quality of life for the impacted community.
6. We can use cloud seeding to reduce the impact of drought.
Cloud seeding activities encourage condensation to form around more dust and ice particles in each cloud. When they are present over drought-stricken areas, the lack of moisture in the region can cause the rain to evaporate before it has the chance to hit the ground. Adding more nuclei to the clouds can encourage heavier snows or rain events to occur, increasing the chance that some of the moisture will reach the dry ground below. This advantage isn’t a guarantee of relief, but it could add more water condensation into the weather patterns so that the incidents that do occur are less frequent.
7. It can help us to reduce the issues that occur with precipitation damage.
Hail damage in the United States can cause more than $20 billion in damages annually to cars, homes, people, and crops. The Insurance Information Institute reports that there were over 4,600 significant hail storms in 2018. Using only State Farm as an example, policyholders experienced $2.7 billion in losses in 2018. There were 508 hail events in Texas, 493 in Kansas, and 332 in Colorado. Over 10 million properties experience damage because of this one specific form of precipitation.
Cloud seeding offers us an alternative that can save money because it can alter the precipitation profile of a cloud. By offering more nuclei, there are fewer opportunities for hail to recycle and grow larger. Some efforts could even transform hail into rain or snow.
8. The cost of cloud seeding can be offset by regional contribution efforts.
Colorado has had a cloud seeding program in place since the 1970s. The effort costs about $1 million per year to manage. The expense isn’t paid for by local residents. Water districts as far away as Los Angeles contribute to the program because snow melting in the Rocky Mountains will create better supplies in the surrounding river basins. Precipitation from Colorado sustains over 30 million people per year.
There are currently eight states that have active cloud seeding programs. Many of them are in the Rocky Mountain region or benefit directly from snows that happen in that area. Arizona, California, and Nevada have an agreement with Utah, Wyoming, New Mexico, and Colorado to split the annual commitment costs.
9. Ground-based machines can contribute to cloud seeding efforts.
Airplanes are not the only way to contribute more nuclei to clouds so that more precipitation occurs. Some states rely on machines that release these materials from the ground. If these options are placed at high altitudes where clouds like to form in the first place, then the benefits can be just as measurable as a pilot dropping silver iodide smoke into a cloud or flying through one with flares on the wings.
Even small increases create large benefits. People in the western portion of the United States are consistently in water-stressful situations. Places along the Colorado River have people being promised more water than is available. A 10% increase can sustain an additional 150,000 homes throughout an entire year.
List of the Disadvantages of Cloud Seeding
1. Specific atmospheric conditions must exist for cloud seeding to work.
Cloud seeding will not work if there are clear skies in the forecast. The correct atmospheric conditions must be present for this technique to work. Clouds that are capable of rain are the only ones that respond well to this effort. When airplanes fly through them, then the seeds they release provide more nuclei that help to form condensation points that can lead to rain or snow. If you were to fly on a clear day to release silver or potassium iodide, then the released chemicals would simply fall to the ground without doing anything.
2. Cloud seeding requires us to use potentially dangerous substances.
Cloud seeding happens when we release specific chemicals or substances into the clouds. The goal is to create seeds that can attract condensation, but this process doesn’t always work. There are times when airplanes can seed clouds and have nothing happen. If we’re releasing solid carbon dioxide or liquid propane into the sky, then these elements could become part of the local environment.
Silver iodide is not currently listed as being harmful to human health in the quantities used for cloud seeding. We also don’t know a lot about this activity, and scientists disagree on its overall effectiveness. These unknowns are a disadvantage that must be taken into consideration.
3. The effectiveness of cloud seeding is still under review.
Cloud seeding is not a 100% guarantee. We can deliver new nuclei into clouds that look like they’ll spawn rain only to receive zero results. The best successes happen when dark clouds receive additional nuclei since there is an expectation that they’ll release precipitation quickly anyway. If you try to add seeds to the typical fluffy white clouds that float along under a blue sky, you’re at a 50/50 chance at best to experience a positive outcome.
Since that means we need to seed clouds that are highly likely to produce rain, some regions of the world may not have many opportunities to use this technology. Some regions receive most precipitation events through thunderstorms, an event that aircraft aren’t always recommended to fly through thanks to the presence of lightning.
4. Cloud seeding is an expensive venture.
When cloud seeding takes place under ideal conditions, then it can increase the levels of precipitation locally by up to 15%. According to Smithsonian Magazine in 2014, the cost of an active program could be as high as $427 per acre-foot. That means the expense of producing additional precipitation would be higher than the economic benefits it provides. Even if we were to take the lowest cost estimates published, it would be somewhere between $27 to $53 per acre-foot to produce additional precipitation.
The results of this study show that cloud seeding won’t solve every problem. It could be a tool that we can use that turns a bad year into an average one.
5. This work could alter weather patterns in other areas.
When clouds receive seeds that encourage more rainfall in a specific area, then that activity could rob other regions of the moisture that they’d typically receive. There are times when this technology helps to regulate the weather locally, but it can also change the patterns of what other people receive hundreds of miles away. If we solve a drought problem in one region, then we might create another one somewhere else. Artificially changing what clouds typically do by themselves requires us to think about the equal and opposite reaction that could happen with the choices we make in this area.
6. The impact of long-term exposure to cloud seeding is unknown.
Most people receive low levels of silver exposure from their drinking water and food. It is present in soil and water deposits all over the world. You can also have it come from anti-bacterial compounds, medicines, and even photographic film. Exposure to high levels of it over time can result in argyria, which changes the coloration of the skin permanently. The EPA does not have an enforceable standard for it in the drinking water, but secondary concentrations of 100 ppb or lower are recommended.
Cloud seeding may not reach the EPA secondary threshold, but these activities will double the silver iodide concentration at ground level. This result can impact plant life and animal habitats in unpredictable ways.
7. The studied benefits of cloud seeding are within the scope of natural variation.
Research into cloud seeding shows that it is most effective during about 30% of the storms that happen during a summer or winter season. That means the 5% to 15% benefits that are possible with this activity are a challenge to evaluate. That places the additional rain or snowfall within the natural variation of a storm. Water districts are willing to take chances on investment here since the work is rather cheap. Any results that become possible will help entire communities have access to more water.
That doesn’t mean it is proven to work. It is a reflection of the hope that it could work, and people are okay with the technology and process if it does not for some reason.
8. Cloud seeding could produce different forms of weather-related damage.
The goal of cloud seeding is to prevent hail and other forms of damaging precipitation in some regions. When we transform ice into water to create more rain or snow, then we are increasing the risk of other adverse events. Flooding is a significant issue that can happen from this work. Dry ground does not readily absorb moisture, which is why flash floods can be a significant problem in deserts. Communities in regions that experience chronic water shortages are often ill-equipped to manage a sudden surge of water availability.
Floods can damage crops just as easily as large hail. Excessive snow can grind economic activities to a halt. There are legitimate concerns that the disadvantage of cloud seeding is that you’re solving one problem by creating another problem that requires management in the future.
Utah initiated a cloud seeding program during the winter of 2012 to see what would happen to their local snowpack. The results showed that there was an 11% increase in precipitation during the active period of this project compared to the times when no seeding occurred. Similar results have been achieved around the world when duplicating this activity.
We also know that cloud seeding can work to reduce fog and hail events locally. This change in the weather can help us to manage our crops better, keep our transportation networks active, and reduce economic damages from adverse events.
The science of cloud seeding may still be inconclusive in 2019, but there are some studies that show this work can provide positive results.
As we continue to look at this work, the advantages and disadvantages of cloud seeding will become ever-more important to evaluate.
Keith Miller has over 25 years of experience as a CEO and serial entrepreneur. As an entrepreneur, he has founded several multi-million dollar companies. As a writer, Keith's work has been mentioned in CIO Magazine, Workable, BizTech, and The Charlotte Observer. If you have any questions about the content of this blog post, then please send our content editing team a message here.