by With cloud seeding, it could rain, but it does not pour or flood really – at least nothing like what drenched the United Arab Emirates and paralyzed Dubai, meteorologists said.
Cloud seeding, although decades old, is still controversial among the weather community, mainly because it has been difficult to prove that it does much. No one reports the kind of flooding that doused the UAE on Tuesday, which is often deployed on technology in an attempt to squeeze every drop of moisture from a sky that usually gives less than 4 or 5 inches (10 to 13 centimeters) of rain in face of the year. .
“It’s definitely not cloud seeding,” said private meteorologist Ryan Maue, former chief scientist at the US National Oceanic and Atmospheric Administration. “If that happened with cloud seeding, they would have water all the time. You can’t create rain out of thin air per se and get 6 inches of water. That’s like perpetual motion technology.”
Meteorologists and climate scientists said the heavy rain is similar to what the world expects from human-caused climate change, and one way to be sure it wasn’t caused by tinkering with clouds is that it was predicted days in advance. Atmospheric science researcher Tomer Burg cited computer models that six days earlier had predicted several inches of rain – the typical amount for an entire year in the UAE.
Three low pressure systems created a train of storms moving slowly along the jet stream – the river of air that moves weather systems – towards the Persian Gulf, said climate scientist Michael Mann of the University of Pennsylvania. Blame cloud seeding ignore the forecasts and the reason, he said.
Mann and other scientists said that many of the people who point to cloud seeding are climate change deniers who want to draw attention to what is really happening.
“When we talk about heavy rains, we have to talk about climate change. Focusing on cloud seeding is misleading,” said Imperial College of London climate scientist Friederike Otto, who leads a team that quickly attributes weather extremes to global warming. yes. “Rain is getting much heavier around the world as the climate warms because a warmer atmosphere can hold more moisture.”
WHAT IS NATIONAL SEEDING?
The clouds need tiny amounts of water or ice droplets called nuclei to make rain. The weather modification method uses ground-based planes and cannons to shoot particles into the clouds making more nuclei, attracting moisture that falls as snow and rain. Usually silver iodide is used, but dry ice and other materials can also be used. The method, first pioneered in the 1940s, became popular in the Western United States beginning in the 1960s, primarily for snow.
It cannot create water from a clear sky – particles must be shot into a storm cloud that already holds moisture to get it to fall, or to fall more than it would otherwise naturally.
HOW EFFECTIVE IS IT?
A recent study of aerial seeding found a clear precipitation pattern on radar that indicated the seeding and provides evidence that the method works. But it’s not clear how effective it is, scientists say.
The physics make sense, but the results have been so small that scientists can’t agree on whether it’s fair to say it really works, Maue and Mann said.
Atmospheric forces are so massive and chaotic that cloud seeding is technically “too small a scale to create what happened,” Maue said. Cloud seeding wouldn’t bring much additional rain, both said.
WHO USES IT?
Despite not knowing its effectiveness, governments in drought-prone regions such as the Western US and the UAE are often willing to invest in a technology like seeding in the hope of getting even a small amount of water.
Utah estimates that cloud seeding helped increase its water supply by 12% in 2018, according to an analysis by the state’s Division of Water Resources. The analysis used estimates provided by the contractors who were paid to carry out the seeding.
Dozens of countries in Asia and the Middle East also use cloud seeding.
The US Bureau of Reclamation spent $2.4 million last year on a cloud seeding along the heavily obstructed Colorado River. Utah recently increased its seeding budget tenfold.
SO WHAT WAS ON SALE?
That part of the Middle East doesn’t get a lot of storms, but when it does happen, it’s the people in the United States who experience it, Maue said.
“Massive tropical storms like this are not uncommon events for the Middle East,” said University of Reading meteorology professor Suzanne Gray. She cited a recent study that analyzed nearly 100 such events over the southern Arabian Peninsula from 2000 to 2020, with most in March and April, including a March 2016 storm that dropped 9.4 inches (almost 24 centimeters ) on Dubai in a few hours.
The 2021 study said “a statistically significant increase in the duration (of loud storms) was found across the southeastern Arabian Peninsula, suggesting that such extreme events may be more impactful in a warming world.”
While cloud seeding can work around the edges, it doesn’t do big things, scientists say.
“Maybe it’s a little human perception that, yes, we can control the weather like Star Trek,” said Maue, who was appointed to NOAA by then-President Donald Trump. “Maybe on long time scales, climate time scales, we’re affecting the atmosphere on long time scales. But when it comes to controlling individual rain storms, we’re nowhere near that. And if we would be able to do that, I think we would be able to solve much more difficult problems than creating a rain shower over Dubai.”
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Borenstein reported from Washington, Peterson from Boulder, Colorado.
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