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While the heavy rainfall was part of a larger storm system in the region, some have blamed the use of cloud seeding. But what exactly is this technique?
On Tuesday, the United Arab Emirates got hit with the most rain it’s recorded in 75 years, causing flooding and temporarily halting flights at the heavily trafficked Dubai International Airport. The flooding resulted in the death of a 70-year-old man whose car was swept away, and there were at least 18 more fatalities in neighboring Oman, including schoolchildren.
By the end of Tuesday, some areas of the UAE had received as much as 10 inches of rain in 24 hours, the UAE’s National Center for Meteorology said in a statement. Dubai had been hit with 5.59 inches of rain in a 24-hour period. On average, Dubai receives 3.12 inches of rain per year, according to the World Meteorological Organization.
As videos of airplanes weaving through floodwaters like boats spread across social media, the conversation quickly turned to one topic: cloud seeding.
Although the rainfall coincided with a larger storm system that hit other countries in the region, including Oman and Iran, some people were quick to blame the UAE’s use of this decades-old technique to artificially stimulate precipitation in the atmosphere.
The UAE has denied cloud seeding took place prior to the rain that started on Monday night.
Cloud seeding has become a popular target in the wake of other rain events. In California, people were quick to point a finger at cloud seeding after storms hit the state in February, despite the fact that California’s cloud seeding pilot program hadn’t started yet. Fact-checkers at Reuters have also previously debunked similar claims that heavy rainfall in Australia in 2022 was linked to cloud seeding.
But what exactly is cloud seeding?
The technique works by artificially creating the conditions under which rain occurs in nature, says Auroop Ganguly, a distinguished professor in Northeastern University’s College of Engineering.
Small droplets of water vapor in clouds will coalesce around dust particles, pollen or even salt from the ocean. Eventually enough water collects around these aerosoles to form an ice crystal that falls and, if it’s warm enough, melts, creating rain.
Cloud seeding gets this process started by “seeding” clouds with a substance like silver iodide, giving the water droplets something to cling on to so the precipitation process will trigger. This usually is done using specialized drones or generators on the ground.
It seems futuristic, but cloud seeding has been done for over 60 years. Ganguly says cloud seeding has become particularly useful in “arid regions to ensure water supply and replenish groundwater.” With its dry, rain-light environment, the UAE has been using cloud seeding since the 1990s.
While the link between cloud seeding and flooding is still unfounded, there are other concerns regarding the practice that should be considered, Ganguly says.
“While the implications for environmental pollution are lower probability unless the experiment goes seriously wrong, it cannot be discounted entirely,” Ganguly says. “The implications for longer-term climate are not well understood.”
The efficacy of cloud seeding is also worth considering to address complex problems such as water shortages or climate change, wrote Laura Kuhl, an assistant professor of public policy and urban and international affairs at Northeastern.
“Cloud seeding is perhaps the ultimate silver bullet, in which literal silver in the form of silver iodide is infused into clouds, causing ice crystals to form and water to condense into rain or snow. Cloud seeding is a form of planned weather modification,” she said.
A 2003 report from the National Academy of Sciences was uncertain about the effectiveness of cloud seeding. However, a 2020 study from the U.S. National Science Foundation found proof that it does work, albeit with limitations. The UAE says cloud seeding helps it increase rainfall between 10% and 30%, while California officials said it helps increase rain by about 5% to 10%.
Ganguly says that “while a complete ban [on cloud seeding] everywhere may not be justified, there is a need for caution” around the practice.
“One question to explore is what other alternatives may exist (e.g., is desalination an alternative?) and what are the tradeoffs,” Ganguly says.
A focus on more basic things like infrastructure investment can get lost amid all the conversation about pie in the sky practices like cloud seeding, Ganguly adds.
“The other point is that mundane things get less noticed: Often major floods in a city relates to urban drainage and related infrastructures, and a city which experiences heavy rainfall very rarely, may be woefully unprepared for such events, thus increasing the propensity for flooding when such extreme precipitation events do happen,” Ganguly says.
Ganguly warns that while cloud seeding might have its uses, there are too many unknowns to put much faith in it as a silver bullet solution.
“The cloud seeding phenomenon where humans try to influence the weather brings to mind, as a rough analogy only, the freakonomics-type solutions to global warming by injecting chemicals like sulfur dioxide into the atmosphere,” Ganguly says. “Such meddling of the atmosphere, especially over longer time scales and larger regions, may have side effects that we may not even understand too well, let alone [know how to] deal with.”