Trying to Pull Water From Clouds
Middle Eastern Countries Race to Make the Skies Rain Over Their Parched Land
ABU DHABI, United Arab Emirates — Iranian officials have worried for years that other nations have been depriving them of one of their vital water sources. But it was not an upstream dam that they were worrying about, or an aquifer being bled dry.
In 2018, amid a searing drought and rising temperatures, some senior officials concluded that someone was stealing their water from the clouds.
“Both Israel and another country are working to make Iranian clouds not rain,” Brigadier General Gholam Reza Jalali, a senior official in the country’s powerful Revolutionary Guards Corps, said in a 2018 speech.
The unnamed country was the United Arab Emirates, which had begun an ambitious cloud-seeding program, injecting chemicals into clouds to try to force precipitation. Iran’s suspicions are not surprising, given its tense relations with most Persian Gulf nations, but the real purpose of these efforts is not to steal water, but simply to make it rain on parched lands.
As the Middle East and North Africa dry up, countries in the region have embarked on a race to develop techniques to squeeze rain drops out of clouds that would otherwise float fruitlessly overhead. With 12 of the 19 regional countries averaging less than 25 centimeters of rainfall a year, a decline of 20 percent over the past 30 years, their governments are desperate for any increment of fresh water, and cloud seeding is seen by many as a quick way to tackle the problem.
And as wealthy countries like the emirates pump hundreds of millions of dollars into the effort, other nations are joining the race, trying to ensure that they do not miss out on their fair share of rainfall before others drain the heavens dry — despite serious questions about whether the
technique generates enough rainfall to be worth the effort.
Morocco and Ethiopia have cloud-seeding programs, as does Iran. Saudi Arabia just started a large-scale program, and a half-dozen other Middle Eastern and North African countries are considering it. China has the most ambitious program worldwide, with the aim of either stimulating rain or halting hail across half the country. It is trying to force clouds to rain over the Yangtze River, which is running dry in some spots.
While cloud seeding has been around for 75 years, experts say the science has yet to be proven. And they are dismissive of worries about one country draining clouds dry at the expense of others. The life span of a cloud, in particular the type of cumulus clouds most likely to produce rain, is rarely more than a couple of hours, atmospheric scientists say. Clouds rarely last long enough to reach another country, even where countries are close together.
But several Middle Eastern countries are pushing ahead with plans to wring any moisture they can from otherwise stingy clouds. Today, the regional leader is the United Arab Emirates. As early as the 1990s, its ruling family recognized that maintaining a plentiful supply of water would be as important as the nation’s huge oil and gas reserves in sustaining its status as the financial capital of the Persian Gulf.
While there had been enough water to sustain the tiny country’s population in 1960, when there were fewer than 100,000 people, by 2020 the population had ballooned to nearly 10 million. And the demand for water soared, as well. United Arab Emirates residents now use roughly 556 liters per person a day, compared with the world average of 178 liters, according to a 2021 research paper.
That demand is being met by desalination plants, but each facility costs $1 billion or more to build and requires prodigious amounts of energy to run, said Abdulla Al Mandous, the director of the emirates’ National Center of Meteorology and Seismology and head of its cloud-seeding program.
After 20 years of research and experimentation, the center runs its cloud-seeding program with near military protocols. Nine pilots rotate on standby, ready to fly as soon as meteorologists spot a promising weather formation.
The United Arab Emirates uses two seeding substances: the traditional material made of silver iodide and a new substance developed at Khalifa University in Abu Dhabi that uses nanotechnology that researchers there say is better adapted to hot, dry conditions.
The pilots inject seeding material into the base of the cloud, allowing it to be lofted thousands of meters by powerful updrafts. And then, in theory, the seeding material, made up of water-attracting molecules, bonds to the water vapor particles that make up a cloud. That combined particle attracts more water vapor particles until they form droplets, which eventually become heavy enough to fall as rain.
But many in the scientific community doubt the efficacy of cloud seeding altogether.
“The problem is that once you seed, you can’t tell if the cloud would have rained anyway,” said Alan Robock, an atmospheric scientist at Rutgers University in New Jersey and an expert in evaluating climate engineering strategies.
Israel halted its program in 2021 after 50 years because it seemed to yield at best only marginal gains in precipitation. It was “not economically efficient,” said Pinhas Alpert, an emeritus professor at the University of Tel Aviv who did one of the most comprehensive studies of the program.
Cloud seeding got its start in 1947, with General Electric scientists working under an American military contract to find a way to de-ice planes and create fog to obscure troop movements.
While the underlying science seems straightforward, in practice, there are numerous problems. Even a cloud seemingly suitable for seeding may not have enough moisture. Sometimes the effect of seeding can be larger than expected, producing too much rain or snow. Or the winds can shift, carrying the clouds away from where the seeding was done.
“You can modify a cloud, but you can’t tell it what to do after you modify it,” said James Fleming, a scientist at Colby College in Maine.
Despite the difficulties, Mr. Al Mandous said the emirates’ methods were yielding at least a 5 percent increase in rain annually — and almost certainly far more. But he acknowledged the need for more data.
Over last New Year’s weekend, Mr. Al Mandous said, cloud seeding coincided with a storm that produced 14.2 centimeters of rain in three days — more than the United Arab Emirates often gets in a year.
Like many scientists who have tried to modify the weather, he is ever optimistic. There is the new cloud-seeding nanosubstance, and if the emirates just had more clouds to seed, he said, maybe they could make more rain for the country.
And where would those extra clouds come from? “Making clouds is very difficult,” Mr. Al Mandous said. “But, who knows, maybe God will send us somebody who will have the idea of how to make clouds.”