Expert warns cloud‑seeding ‘didn’t work’ as Puerto Rico revives tactic amid deepening drought
By THE STAR STAFF
A former member of Puerto Rico’s Drought Committee is warning that cloud‑seeding remains an unreliable and largely unproven tool for the island, even as the government has restarted operations over the Carraízo and La Plata reservoir basins to confront an intensifying water crisis.
Dr. Pablo Menéndez Lázaro, who advised the government during the 2015 drought, said in a radio interview that the method relies heavily on probabilities and cannot guarantee rainfall over Puerto Rico’s narrow catchment zones.
“Controlling the dart throw so that the cloud releases precipitation over the catchment area is extremely complicated,” he said, noting that regions with vast basins -- such as Texas, Mississippi, or the Amazon -- have far more tolerance for error.
Menéndez stressed that cloud‑seeding requires complex coordination and is subject to uncontrollable variables like wind direction and speed. He recalled that the Drought Committee advised against the technique in 2015, when the government attempted it with limited results.
“It didn’t work,” he said. “We cannot say it was effective.”
His concerns echo findings from a 2024 report by the U.S. Government Accountability Office (GAO), which concluded that cloud‑seeding’s benefits remain unproven despite decades of use. The GAO found that studies estimate additional precipitation ranging anywhere from 0 to 20%, but that evaluating effectiveness is extremely difficult due to unreliable data, unpredictable cloud conditions and inconsistent reporting across states.
The report also noted that cloud‑seeding can only work when the right type of clouds are present, a major limitation for regions experiencing severe drought. While existing research suggests current levels of silver iodide do not pose environmental or health risks, the GAO warned that the effects of more widespread use remain unknown. The agency identified gaps in federal oversight and said the public often misunderstands cloud‑seeding, confusing it with long‑term geoengineering.
Despite the warnings, the Puerto Rico Aqueduct and Sewer Authority (PRASA) has moved forward with a new cloud‑seeding program, contracting Seeding Operations & Atmospheric Research (SOAR) on an expedited basis for $400,000, or $66,500 per month, to carry out operations over the Carraízo and La Plata basins.
It is the same company hired in 2015, when the government attempted to induce rainfall to ease rationing at Carraízo, La Plata and Cidra. The final report from that effort found that only one of 27 seeding events produced significant rainfall. Three had moderate effects, 16 minimal, and seven produced none.
The renewed push comes after engineer Carlos Pesquera Morales met at La Fortaleza with PRASA Executive President Luis González Delgado to discuss emergency measures amid declining reservoir levels. Pesquera described cloud‑seeding as a complementary tool alongside other initiatives, such as rehabilitating northern aquifer wells.
“This only works if there is humidity,” Pesquera told reporters, emphasizing that the technique does not create clouds but attempts to stimulate existing moisture to produce rain over affected reservoirs.
Menéndez aired his doubts about the efficacy of cloud-seeding a day after Gov. Jenniffer González Colón announced that the government had reactivated the program to increase precipitation over the Carraízo, La Plata and Cidra reservoirs.
“The hiring of a company that was hired in 2014 and 2015 for cloud seeding began on Friday of last week,” González Colón said, referring to SOAR, in response to questions from the press.
The governor said the procedure requires that there be clouds over the areas of interest and that atmospheric conditions allow the operation to be carried out. She said the company used a decade ago then achieved precipitation increases of between 5% and 15%.
“In our case, for Carraízo and for La Plata, five percent is gold when we have nothing,” she said.
González Colón said the program began last weekend, after the presence of dust from the Sahara decreased, and that cloud systems that could favor precipitation over the reservoirs will be taken advantage of.
She noted that La Plata, Cidra and Carraízo are among the bodies of water that require greater attention and that she still did not have a report available on the runoff produced since the beginning of operations.
Meanwhile, as drought conditions intensify across the island and pressure mounts to secure water supplies for the metropolitan region, Puerto Rico is once again betting on a strategy that experts -- and federal researchers -- say remains scientifically uncertain and operationally constrained. Whether cloud‑seeding will produce any measurable relief this time remains an open question.
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