What causes heavy rains in Dubai?

For meteorologists and climatologists, this extreme rainfall is an example of the disruptions the world must now expect due to climate change.

For meteorologists, Cloud seeding may not be responsible for the torrential rains that paralyzed Dubai this week.

This method, although it has been used for several decades, is still controversial in the meteorological community, mainly because its effectiveness is difficult to prove.

But Cloud seeding has never led to flooding like the UAE experienced this week. Earth often uses technology to try to wring every last drop of moisture from a sky that usually yields only 10 to 13 centimeters of rain per year.

“Cloud seeding is not the culprit. Otherwise there would be water all the time. You can’t create 15 centimeters of rain out of nothing.”suggests private meteorologist Ryan Maue, former chief scientist of the US National Oceanic and Atmospheric Administration.

This was stated by meteorologists and climatologists this extreme rainfall is an example of the disruptions the world must now expect due to climate change.

According to them, the fact that this precipitation was forecast several days in advance is irrefutable evidence that cloud modification is not responsible.

Tomer Burg, an atmospheric scientist, points to computer models that six days earlier had predicted a few centimeters of rain – the average amount for an entire year in the United Arab Emirates.

According to Michael Mann, a climatologist at the University of Pennsylvania, three low pressure systems formed a storm front that moved along the jet stream— a corridor of strong winds in the upper atmosphere — towards the Persian Gulf.

The charge of cloud seeding ignores these factors, he adds.

Many of those who point the finger at this method are also climate change deniers who are trying to distract attention from what is really happening, say Michael Mann and other scientists.

“When we talk about heavy rainfall, we have to talk about climate change. Focusing on cloud seeding is wrong”says Friederike Otto, a climatologist at Imperial College London, who leads a team tasked with rapidly studying extreme weather events to determine whether or not they are caused by global warming.

“Precipitation is increasing worldwide as the climate warmsbecause a warmer atmosphere can hold more moisture”she explains.

What is cloud seeding?

Clouds need tiny droplets of water or ice, called nuclei, to produce rain. Using planes and ground cannons, this method involves sending particles into the clouds to form more nuclei, thereby attracting moisture that falls as snow or rain.

Usually silver iodide is used, but it can also be dry ice or other materials. This method, developed in the 1940s, became popular in the western United States in the early 1960s, primarily to stimulate snowfall.

On the other hand, it does not create water in a clear sky: particles must be thrown into a storm cloud that already contains moisture in order to fall or to fall more abundantly.

Does cloud seeding work?

A recent aerial seeding study found a correlation between precipitation and cloud seeding, proving that the method works. But not all scientists are convinced of its relevance.

If results are observed, they are usually so weak that scientists cannot agree that this method really workssay Ryan Maue and Michael Mann.

Atmospheric forces are so enormous and chaotic that, technically, cloud seeding occurs “is on too small a scale to create what happened”, says Ryan Maue. Both say additional precipitation from cloud seeding would be minimal.

Who uses cloud seeding?

Even before determining their effectiveness, governments in drought-stricken regions such as the western United States and the United Arab Emirates are often willing to invest in technologies such as seeding in the hope of obtaining even a small amount of water.

Utah estimates cloud seeding helped increase water supply by 12% in 2018, according to an analysis by the state Department of Water Resources. The analysis relied on estimates provided by contractors who were paid to seed.

Dozens of countries in Asia and the Middle East also use cloud seeding.

Last year, the US Bureau of Reclamation spent $2.4 million on cloud seeding along the swollen Colorado River. Utah recently increased its initial budget tenfold.

So what caused the deluge of rain that hit Dubai?

“This part of the Middle East doesn’t see many storms, but when they do, they’re huge”explains Ryan Maue.

Giant tropical storms of this type “not rare events for the Middle East”says Suzanne Gray, Professor of Meteorology at the University of Reading.

She cites a recent study that mentions nearly 100 such events in the southern Arabian Peninsula between 2000 and 2020, most of them in March and Aprilincluding the March 2016 storm that dropped almost 24 centimeters on Dubai in just a few hours.

According to a 2021 study “statistically significant increase in duration [grosses tempêtes] in the southeast of the Arabian Peninsula was recorded, which suggests that these extreme events could have an even greater impact in a warming world“.

According to Ryan Maue, it is presumptuous to think that humans can cause such weather phenomena using an artificial method such as cloud seeding.

“On long timescales, climate timescales, we can certainly affect the atmosphere. But when it comes to controlling individual rainstorms, we’re way off the mark. What if we were able to do that, I think we could solve much more difficult problems rather than making a splash in Dubai.”he concludes.