Cloud Seeding Technologies
Cloud Seeding Technologies
By: Megan Heuschel
Science Article: https://link.springer.com/article/10.1007/s00376-025-4476-8
News Article: https://www.dongascience.com/en/news/65252
Background: Cloud seeding is a temporary local weather modification with various application and procedural methods. Used in both warm and cold season clouds, seeding is used to enhance or induce desired precipitation. Seeding is beneficial especially in areas prone to drought or severe thunderstorms that drop hail. Currently, cloud seeding is legal throughout the U.S.; 9 states currently implement this technology, while others have banned it outright. Feelings about seeding are controversial due to the unknown long term climate effects that may result in negative Earth system outcomes.
The science article covers cloud seeding technologies and the success of different methodologies throughout South Korea, observing precipitation levels and cloud activity at 17 monitoring sites throughout the country. The article explains how cloud seeding has been difficult to quantify and measure, thus producing uncertainty as to the effectiveness and durability. There are a multitude of cloud seeding uses, including but not limited to agricultural, municipal, environmental, and recreational purposes. Benefits to cloud seeding include lessening drought threats to certain types of crops, fish, plants, ecosystems, and even hydroelectric dams. It can also help lessen the damage caused by severe thunderstorms that produce large amounts of hail, as well as help fill local waterways. Currently, there is limited research and funding available for the efficacy of these technologies, and it is hard to measure the actual effect or success of seeding. This comes from the uncertainty of precipitation had the seeding not occurred, as well as how much precipitation is attributed to the seeding itself, apart from how much precipitation would have happened without seeding.
Nonetheless, studies in Korea prove optimistic outcomes from cloud seeding experiments. AgI was used as a seeding material for cold clouds, whereas CaCl2 was used for warm clouds. Varying only in material, the study measured mean precipitation and average particle size after coalescence, ultimately determining July had the highest precipitation and cloud activity, while January had the lowest, depending heavily on the amount of present water vapor in the atmosphere. Ultimately, the study found that clouds with seeding experienced depleted atmospheric water vapor levels as the growth of cloud droplets increased and stronger updrafts catalyzed conversion of these droplets into raindrops.
Overall, the increase in monthly mean precipitation from seeding was highest in summer, lowest in winter, and moderate during the spring and autumn. Thus, cloud seeding proves to be an optimistic course of action for further water resource management, with additional research needed on the exact microphysical processes that allow for a more tailored approach to cloud seeding.
The news article describes Korea’s newest attempts at implementing long term artificial rain projects, with the dedication of two new weather aircraft, new ground-based generators, and one new fixed-wing, rain-inducing drone. This was accompanied by a 7.3 billion won budget and the scheduling of 77 new artificial rain inducing experiments to be carried out over the next 4 years. The cloud seeding experiments will also measure the scale between the weather planes and drones, since a drone offers more launch flexibility, while the planes offer a payload capacity 12 times larger than its unmanned counterpart.
The article describes the new aim is both wildfire prevention and overall weather control, especially in generally arid regions like the mountainous sections of Korea. This demands a stronger understanding of the clouds unique to the Korean peninsula, as well as the further environmental impacts and infrastructural considerations. This artificial rain is designed to help mitigate extreme weather backlash and induce precipitation most effectively, but requires more dedicated funding towards artificial rain advancements.
Analysis: The shortcomings of both articles include the environmental impacts of cloud seeding, whether beneficial or detrimental. Glossing over the potential hazards of iodine- or chloride- rich rainfall, prolonged cloud seeding aftermath, or hazardous seeding pollution, neither article truly mentioned the environmental impacts of cloud seeding. Research is further needed to accurately analyze the second and third order effects of cloud seeding and what environmental factors can be both attributed to or delineated from seeding. The news article would receive a 7 rank due to its descriptive and optimistic tone, yet does not cover much of the potential risks or public pushback that may be induced by a long term experiment like this one. Otherwise, the agreement between the peer-reviewed article and the news article is strong, as the news article offers an implementation strategy and an update to the current events unfolding in Korea’s environmental efforts. The articles agree that cloud seeding is the new face of weather modification and control, and describe steps taken by the government with long-term goals of neutralizing potential threats in the future. The most important issue is cloud seeding is a potentially effective course of action to environmental cohesion between man and nature, yet remains contentious and uncertain of what future endeavors might entail. Seeding is just one method of coexisting with nature and tackling the multifaceted issue of climate change; there is more to be understood and taken action on in other realms of weather modification and environmental engineering.
Hi Megan, I enjoyed reading your post about the potential benefits and uncertainties of cloud seeding. I feel very interested in reading this blog. I would love to know more about the particle size as you mentioned that they measured the average particle size like how do you think the size of the seeding particles affects the amount of precipitation produced? Also, do you think researchers should explore alternative compounds to silver iodide (AgI) and calcium chloride (CaCl₂) to reduce potential environmental risks, as we know halogenated compounds deplete our ozone layer?
ReplyDeleteHi Shatabdi, your question is really good and I was honestly wondering the same thing! The article states the AgI compound was used for cold weather clouds, while the CaCl2 compound was used for warm weather clouds. Because the most precipitation was recorded from the warm/summer months, we know this season was the most responsive to cloud seeding. However, the article mentions this is the case due to the increase of atmospheric water vapor, and not dependent on particle size. The article does not declare why AgI was used for colder clouds, and CaCl2 for warmer, other than this was the precedence established by other experiments and proves to be the most effective per cloud type. My best guess would be that since the AgI compound is larger and heavier, it works best with cold weather clouds to promote stronger/faster droplet collisions within the cloud, resulting in large droplets that specifically help with snowfall. On the other hand, CaCl2 is a smaller compound that probably reacts to form droplets within the warm season clouds at a slower rate, creating smaller droplets and resulting in smaller/lighter droplets that are easily released as rainfall.
DeleteHello Megan, your blog post was very interesting to me. I personally didn't know that we did cloud seeding or even what it was. this post was very informational for me and i wanted to say thank you. i was wondering how could long-term cloud seeding affect the environment, especially if chemicals such as AgL and CaCl2 are used repeatedly, wouldn't this kind of off set the earths natural tendencies and basically make the earth think "oh i don't have to do this if its controlled already"?
ReplyDeleteHi Bryanna, great question! I too wonder about long-term cloud seeding effects, and what makes these predictions difficult is that cloud seeding is relatively new, and so the only long-term effects we know about are purely the ones speculated on. Because these experiments are newly ongoing, we can only rely on simulations and predictions to anticipate the potential side effects of cloud seeding. However, current debate mentions the bioaccumulation of silver iodine and chloride compounds in our atmosphere. While these are naturally occuring compounds, long-term/chronic cloud seeding could potentially cause concentration levels too high for these natural systems to properly dispose of.
DeleteI think it is interesting because in the article they mention that the drone technique only works on clear days. However, I believe most wildfires occur under these conditions. I am curious how this technology can still help in these situations with that huge limitation. If they are not used in wildfire circumstances but as a means to control weather, do you think this is an issue? Is there such a thing as too much science involvement in this, like weather, that maybe should not be controlled?
ReplyDeleteHi Allison, thank you for this! I completely agree that if the push for researching more into this tech is to help mitigate wildfire damages, then the deployment of such technologies should probably be amenable to such harsh atmospheric conditions. I think this type of tech is probably more helpful for drought/hail/snowfall control, as opposed to helping limit the catastrophic conditions of wildfires. I definitely need to learn more about how active controls are placed on wildfires in real time (like planes dumping water over the forests), but -- yes -- in my opinion this type of tech is least likely to be helpful during an active blaze. I am hopeful this could potentially help with agricultural and humanitarian aid efforts, but I would personally like to see proactive and early policies from government officials on how to not OVERuse this potentially helpful environmental modification.
DeleteHi Megan! I found it really interesting that cloud seeding is legal in some states but has been banned in others, especially since there is still so much that isn't known about how effective it actually is. It makes me wonder how much of those differences are based on the science versus concerns about the potential environmental effects. Do you think having more research on the long term impacts, as well as the effectiveness of this practice, could eventually lead to more consistent policies between states?
ReplyDeleteThis was a really interesting read! You mentioned that one problem with the article is that it lacks substantial mention of potential pushbacks or limitations to this type of technology. I'm curious if there was any mention of opinions, either positive or negative, from different sectors like policymakers, the scientific community, or the people residing in areas that employed/wish to employ this technology because I imagine this sort of interference with nature could be controversial to some while popular with others. Did the article mention any common sentiments or any reason to doubt cloud seeding from certain perspectives?
ReplyDeleteHi Megan! This was a really interesting post, great job! I have heard about cloud seeding before, but I had no idea that it was already being used on such a large scale or that South Korea is investing so much into expanding the technology. I thought it was especially interesting that cloud seeding was more effective during the summer and depended so heavily on how much water vapor was already present in the atmosphere. It also surprised me that despite countries investing in this technology, it is still difficult to determine how much precipitation is actually caused by cloud seeding versus how much would have naturally occurred. I also agree that the possible environmental impacts seem like an important issue that both articles could have discussed more. I am curious about what happens to the AgI and CaCl2 after they are released into the atmosphere. Could repeatedly using these materials eventually cause them to build up in the environment, and how would researchers determine whether any long-term effects are actually caused by cloud seeding?
ReplyDeleteHi Jasmine, thank you for your question! After doing some additional research, I discovered that while both AgI and CaCl2 are naturally occurring compounds, they exist in such low concentrations throughout our environment that they are easily handled throughout Earth's biosphere and hydrosphere. However, when cloud seeding occurs, the concentrations of these compounds risks over accumulating, and entering our environment at rates that may be toxic. Essentially, AgI causes water molecules to freeze around it, inducing ice particle formations within the clouds. Prolonged exposure/use of this molecule may cause localized accumulation that could potentially enter watersheds, soil, and lake sediments if overused. Likewise, CaCl2 absorbs water vapor and dissolves into a liquid, depositing into the ground when released in precipitation. While Ca and Cl2 are abundant in nature, repetitive, and localized, deposition of salts can subtly increase the ionic strength and salinity of localized soils and freshwater streams. This has the potential to chemically alter baseline nutrient cycles. Scientists can isotopically tag these particles and measure their concentrations throughout ecosystems, but at the cost of potentially harming delicate and susceptible species like aquatic plants or amphibians.
DeleteHi Megan! I wasn't previously aware of cloud seeding technologies, so this blog was particularly interesting to read. I agree with you that the article does not do a great job of mentioning the potential risks/pushback around implementing a large-scale project like cloud seeding, and I probably would give the article a 7 too. Additionally, I was wondering whether you have any thoughts on why South Korea is promoting cloud seeding while many U.S. states are banning it. I understand the two countries may have different environmental regulations, but I'd love to hear your thoughts on why they may value the technology differently. Maybe because they weigh the importance of increasing water supply/stopping wildfires against the potentially harmful environmental impacts differently?
ReplyDeleteHi Megan, I really liked your blog post. It is very striking to me the news source did not note the potential environmental impacts of cloud seeding. I am wondering if perhaps the article intended this since you did mention it had an optimistic tone. However, I do know people are more prone to narrowing in onto negative statements, which these potential environmental impacts could be categorized in. Do you think it is due to an overall tone or wanting to have a greater emphasis on the benefits than possible downsides?
ReplyDeleteHi Samantha, good point! I also agree that maybe these articles were on the optimistic side of things and intentionally avoided mentioning the environmental impacts. I think it is very possible these qualities were left out in order to push towards more research, more cloud seeding, and ultimately more funding. I believe a more holistic review of cloud seeding would certainly include a thorough description of the potential downsides and negative effects repeated and prolonged cloud seeding can induce.
DeleteHey Meagan, this post is fascinating! I remember learning about cloud seeding freshman year of high school and haven’t really heard much about it since. It’s a shame that there hasn’t seemed to be much progress in the field given the incredible potential this technology has. Although, reading through your post, it’s very clear why that is the case. I think the point you made about the difficulties in verifying the validity of this technique is one of the main reasons why there is so little funding for this type of research. Additionally, there’s also the question of whether or not we should be altering the local climate in such drastic ways. Besides the potential harms of the chemicals used in these studies, like the AgI or CaCl2 you mentioned, the unintended effects on the environment could be extremely unpredictable and destructive. Even if the technology were already perfected, our current understanding of the environment still seems to be insufficient to meddle with such complex systems. What is your opinion on whether or not this technology should be expanded upon? And what opinions do the researchers have on this?
ReplyDeleteI thought this was an interesting post to read. While I have heard about this technology/method before, it wasn't in any scientific, so it is great to learn more about it within that context. I was interested in learning more about why this practice is banned in 9 states, and whither it is due to scientific reasons (such as environmental concerns or a lack of research into potential consequences) or just a bias/ fear of the technology due to a misunderstanding of its operation. Additionally, it would be interesting to learn more about the cons, such as environmental costs, if they exist.
ReplyDeleteHi Carson, very good question! I, too, was wondering about the ban in 9 states, and why this has not been standardized. I think you hit the nail right on the head with this, because to my understanding the bans have occurred due to public pushback. It seems to me these legislations are done proactively (or at least preemptively) based on the perception of what cloud seeding and geoengineering entails. It is my personal opinion that these bans may be a little bit premature, because they disallow for continued research in these fields, based on the idea that too much research will lead to bioaccumulation that cannot naturally be disposed of. However, I think continued research is not a bad thing, but requires additional oversight, guidance, and guardrails from elected officials on how much is too much and how we can ensure there are not too many chemicals being placed into the atmosphere.
DeleteThe idea that humanity can actively engineer the atmosphere to combat climate change while simultaneously on the edge of uncovering massive, untouched scientific mysteries about how our planet reacts to it is quite amazing. Do you think the potential environmental risks of engineering the weather outweigh the benefits? With our problems with global warming and what we discussed about the ozone depletion, I fear anything that could change our environment.
ReplyDeleteHowdy Megan. I am interested in the assertion that the news article makes; that cloud seeding might serve to mitigate wildfires in Korea. Aside from the troubling notion that the artificial rain might contain pollutants/environmental contaminants we have yet to know the effects of, it is also possible that the mitigation of small wildfires would cause large wildfires to have more devastating effects. Often in pine forests deprived of high-frequency and low-severity fires, especially when in dry hot conditions ushered in by the changing climate, when a fire starts, it will accelerate the severity of the fire and clear large areas of trees it likely would not have otherwise ("fire suppression paradox"). I wonder if cloud seeding might potentially contribute to the problem which it attempts to fix; and if not for the mitigation of forest fires, then I wonder who stands to benefit from this.
ReplyDeleteHi Megan! Great work. Two things I overall found interesting from this article were that South Korea is planning 77 artificial rain experiments over the next four years and that they are using both planes and drones for these experiments. I think it’s cool that they are testing different types of technology instead of relying on just one method. I’m curious to see whether the drones will actually be useful enough to make a difference compared to the larger planes? Do you think that this could be an actual feasible technology that they develop in the coming years?
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