Can ‘fog harvesting’ help solve water scarcity in Chile’s Atacama Desert?

- Communities living in Chile’s Atacama Desert, one of the driest places on Earth, look for creative ways to fight water scarcity, including “harvesting” water droplets from the foggy climate. - Local groups erect large mesh structures that can intercept thousands of liters of water droplets per day from fog being carried by the wind. The water is used for drinking and cultivating fruits and vegetables. - Researchers have studied the factors that increase harvesting results, including sea level, temperature, solar radiation, and wind speed. - With more research and support for pilot programs, they say local governments could one day adopt the strategy into their water management plans. Chile’s Atacama Desert is one of the driest places in the world. Some areas only see rainfall a few times in a century, while others have never recorded rainfall at all. In many rural communities there, local governments have to truck in water from other parts of the country or extract it from deep underground wells. But in harder-to-reach settlements, these solutions still aren’t cost-effective or reliable. To address the problem, residents and researchers have looked for more innovative methods of getting water out of the environment. Some have begun using the fog that often blankets northern Chile. Off the Pacific coast, cold air currents cool into low cloud cover that blows inland, getting stopped by coastal mountains and settling at ground level. With the right approach, groups have found ways to “capture,” or “harvest,” the fog, turning it into useable freshwater. “In a very simple way, we have to understand that clouds are made up of water droplets,” Camilo del Río, director of the Catholic University’s Atacama Desert Center in Chile, told Mongabay. “They’re already formed, they’re already condensed. So whenever a cloud is transported by wind and comes into contact with the Earth’s surface, what is touching the surface is thousands and thousands of liters [of water].” Local groups have found ways to harvest enough fog to supplement drinking water and bolster agricultural projects. But many challenges with the strategy still remain. Researchers want to harvest the fog more efficiently and at scale, one day convincing local officials to buy into it and expand. ‘Crazy cloud people’ and the origins of fog harvesting For centuries, groups across the globe have been experimenting with ways to harvest fog and moisture. In the Canary Islands, people collected the water dripping from “fountain trees,” like junipers and pines. In Oman, they built cisterns beneath trees that formed water droplets on their branches. Others tried to build structures conducive to creating condensation. In the early 1900s, researchers in South Africa began modifying rain gauges to figure out how much water vegetation could capture from fog. By 1969, they had developed a more systematic approach to fog harvesting, with plastic screens that would “intercept” water droplets. But much of the advances in fog harvesting have taken place in northern Chile and then spread to other parts of the world. “Fog catchers … are a Chilean invention,” said Orlando Rojas Figueroa, president of the Atacama Fog Catchers Group, which according to Rojas has harvested thousands of liters of water per day, and continues to raise awareness about the practice. In the 1950s, researchers in the region of Antofagasta developed nets that intercepted water droplets. Then, in 1987, the Chungungo fishing community in northern Chile installed one of the biggest projects up to that point: 100 fog collectors capable of providing around 33 liters (8.7 gallons) of clean water per day to the community’s approximately 300 residents. Two poles held up large mesh sheets, the largest measuring 12 by 4 meters (39 by 13 feet), that intercepted the movement of water droplets carried by the wind. The droplets eventually fell from the mesh into a receptacle below and were filtered for drinking. Rojas said he had heard about the project when it was originally installed but didn’t start participating until the 1990s, when a researcher recruited him and several friends. At first, people in nearby communities thought the idea was absurd. “They called them the crazy cloud people,” he said. “People would say, ‘What are these guys going to do with the clouds?’” Nevertheless, they continued to experiment with larger and larger collectors, placing them in different spots around the desert. They found that the tops of hills produced the best results, in those days around 400 liters (106 gallons) of water a day, Rojas said. It required them to drive on isolated roads in the desert and hike for several hours. By 2004, he said, they managed to improve their harvesting results to around 1,000 liters (264 gallons) per day. They’ve been able to harvest 1,400 liters (370 gallons) per day and have reached as much as 12,000 liters (3,170 gallons) per day. The water is used for cultivating potatoes, lettuce, and numerous fruits, including lemons, peaches, pomegranates and figs, among others. The association also sells its water in glass bottles. “A large part of the success … doesn’t depend so much on the physical phenomenon itself, but rather on investment and communities that are well organized and see a benefit in this,” del Río said. “The successful cases happen precisely in those kinds of circumstances.” Scaling up the effort, engaging communities In 2023, researchers in Chile started conducting a study into fog-water collection potential and whether it could really serve as a complementary freshwater resource. They focused on the community of Alto Hospicio, an area that has historically relied almost entirely on groundwater. They used the standard fog collector (SFC), a mesh frame erected on vertical posts, the internationally accepted device for fog-water collection potential. They also used numerous meteorological factors to determine the best locations to set them up, including air temperature, solar radiation, relative humidity, and wind speed. They determined fog collection has the highest potential outside of urban areas, less than 1 kilometer (0.6 miles) from the limits of Alto Hospicio, at spots between 700 and 1,100 m (2,300 and 3,600 ft) above sea level. In those areas, they found they could potentially collect 0.2-4.9 liters of water per square meter of fog-collecting surface per day, or about 0.6-15 ounces per square foot. Based on the study’s estimated collection rates, that means if the community invested in 1,000 m2 (nearly 10,800 ft2) of fog collectors, they could potentially have between 200 and 4,900 liters (about 53-1,300 gallons) of water per day. However, these results are still highly variable, and researchers said they’re hesitant to include hard numbers in discussions about fog-harvesting potential. They said more fieldwork using FSCs needs to be carried out to better understand the potential of fog harvesting in northern Chile. They also said Alto Hospicio officials should consider integrating fog harvesting into the municipality’s water management strategies. That doesn’t mean immediately investing in large, costly infrastructure for fog harvesting, the study said. Instead, officials should first back pilot projects and develop guidelines over several years until there’s a better understanding of how the strategy could be implemented. In addition to determining how much water can realistically be collected, the pilot projects would help officials and residents prepare for storage and distribution challenges, and the cost of using fog harvesting on a municipality-wide scale. “We have the problem, and we also have the solution,” Virginia Carter, lead author of the study and associate researcher at the Atacama Desert Center, told Mongabay. Carter is also an assistant professor at Mayor University and a National Geographic explorer. Last year, Carter started a freshwater conservation project with the backing of the National Geographic Society to provide the Atacama Fog Catchers Group with a fog-monitoring station and scientific analysis of its results. The project also included the installation of a fog-monitoring station in Paposo, a rural coastal town of around 250 people who rely on water trucked in from other parts of the country. Carter is in the process of creating a fog-water map of the area to help improve results. “My goal is to strengthen the role of fog collection in water policy,” she said. “By promoting it, we’ll be able to expand the use of this technology beyond isolated pilot projects. My goal is to create awareness in order to put this water resource on the public agenda in Chile.” Another community-level initiative began in 2022, when Alto Hospicio’s tourism and heritage office conducted a survey of the area’s natural and cultural history. It identified species that depend on fog, specifically Tillandsia plants that absorb water from the air. The location of the Tillandsia gave officials an idea of where fog-harvesting equipment could be installed. With support from the Atacama Desert Center and funding from the Ministry of the Environment, the officials set up four fog harvesters, each capable of collecting 7-10 liters (1.8-2.6 gallons) of water on a foggy day. For now, however, the project’s primary goal is not to provide a complementary source of freshwater but rather to raise awareness about fog harvesting. The tourism and heritage office also organizes tours of the site for residents and school groups. In the future, officials hope to establish a center for environmental and cultural education related to the fog ecosystem, and even make it a tourist attraction. Government buy-in is still a long way off, said Nicolás Prado, an anthropologist and official in the tourism and heritage office, who said he couldn’t speak for the rest of the municipal government. If the practice is going to grow, he said, it will likely happen at the grassroots, community level. “There’s still a lack of confidence. There’s still a lack of political will,” he told Mongabay. “There’s still a need to move beyond the idea of making money from these things. Because in the end, fog collectors are something anyone can build at home with very simple materials: just a little bit of mesh and a couple of posts.” Citations: Keim-Vera, K., Lobos-Roco, F., Aguirre, I., Merino, C., & Del Río, C. (2024). Fog types frequency and their collectable water potential in the Atacama Desert. Atmospheric Research, 312, 107747. doi:10.1016/j.atmosres.2024.107747 Fessehaye, M., Abdul-Wahab, S. A., Savage, M. J., Kohler, T., Gherezghiher, T., & Hurni, H. (2013). Fog-water collection for community use. Renewable and Sustainable Energy Reviews, 29, 52-62. doi:10.1016/j.rser.2013.08.063 Olivier, J. (2004). Fog harvesting: An alternative source of water supply on the West Coast of South Africa. GeoJournal, 61(2), 203-214. doi:10.1007/s10708-004-2889-y Carter, V., Verbrugghe, N., Lobos-Roco, F., Del Río, C., Albornoz, F., & Khan, A. Z. (2025). Unlocking the fog: Assessing fog collection potential and need as a complementary water resource in arid urban lands — The Alto Hospicio, Chile case. Frontiers in Environmental Science, 13. doi:10.3389/fenvs.2025.1537058 Klemm, O., Schemenauer, R. S., Lummerich, A., Cereceda, P., Marzol, V., Corell, D., … Fessehaye, G. M. (2012). Fog as a fresh-water resource: Overview and perspectives. AMBIO, 41(3), 221-234. doi:10.1007/s13280-012-0247-8 Banner image: Flamingos on the Atacama salt lake in Chile. (AP Photo/Karen Schwartz) See related from this reporter: In Honduras, solar power has done more harm than good, communities say FEEDBACK: Use this form to send a message to the author of this post. If you want to post a public comment, you can do that at the bottom of the page.