Iran has feared for years that neighbors are depriving the country of one of its vital sources of water. But the concern was not directed at a dam or an aquifer being drained. In 2018, with severe drought and rising temperatures, authorities concluded that someone was stealing their water from the clouds.
“Israel and another country are mobilizing to stop Iranian clouds from giving rain,” General Gholam Reza Jalali, a senior official in Iran’s powerful Revolutionary Guard, said in a 2018 speech.
The unnamed nation was the United Arab Emirates, which launched an ambitious cloud seeding project, injecting chemicals to try to force fallout. Iran’s suspicions are not surprising given its strained relations with most Persian Gulf countries, but the real aim of the efforts is not to steal water, but simply to make it rain on scorched land.
Faced with the growing dryness of the Middle East and North Africa, countries in the region have embarked on a race to develop chemicals and techniques that make it possible to rip raindrops from clouds that would otherwise just float in the sky.
With 12 of 19 nations averaging less than 25 centimeters of rainfall a year down 20% over the past 30 years, governments are desperate for any additional freshwater sources.
As rich countries like the United Arab Emirates pump hundreds of millions of dollars into the effort, others are joining the race looking to avoid running out of their fair share of rain before all the moisture is drained from the sky. All this despite questions about whether the technique generates enough precipitation to justify the effort and expense.
Morocco and Ethiopia already have cloud seeding programs. Iran too. Saudi Arabia has just started a large-scale program, and half a dozen other countries are considering doing the same.
China has the most ambitious project in the world, aimed at stimulating rain or preventing hail across half the country. It is, in fact, trying to force clouds to produce rain over the drought-stricken Yangtze River.
Cloud seeding has been practiced for 75 years, but experts say its scientific validity remains unproven. They especially reject the idea that one country can drain the clouds and thereby harm others downwind.
According to scientists, the lifetime of a cloud, especially those of the cumulus type, rarely exceeds two hours. Occasionally they can last longer, but rarely long enough to reach another country. Middle Eastern nations reject these doubts.
Today the undisputed leader in the effort is Abu Dhabi. As late as the 1990s, the country’s ruling family recognized that maintaining an abundant supply of water would be as important as the vast reserves of oil and gas in maintaining its status as the financial and business capital of the Persian Gulf.
There was enough water in 1960, when its inhabitants were less than 100,000 people, but by 2020 the population had grown to almost 10 million — and demand followed suit. Today the inhabitants of the Emirates consume 670 liters of water per capita per day; the world average is 214 liters.
Demand is being met by desalination plants, but each costs $1 billion or more to build and requires massive amounts of energy to operate. After 20 years of research, the National Center for Meteorology and Seismology operates its cloud seeding program with quasi-military protocols. Nine pilots take turns on duty, ready to take off as soon as the meteorologists spot a promising meteorological formation.
The country uses two substances for seeding: the traditional silver iodide and a substance that has just been patented, developed at Khalifa University in Abu Dhabi, which uses nanotechnology and would be better adapted to the dry and hot conditions of the Persian Gulf.
Pilots inject the materials at the base of the cloud, letting the updrafts lift them to tens of thousands of feet.
In theory, the seeding material, made up of hygroscopic (water-attracting) molecules, binds to the vapor particles that make up the cloud, attracting more particles to form droplets, which eventually become heavy enough to fall as rain — the Sowing materials, according to scientists, do not have any relevant environmental impact.
In theory. Many members of the scientific community question the tactic’s effectiveness, pointing out among the obstacles the difficulty — or impossibility — of documenting concrete increases in precipitation. “Once you seed the cloud, you can’t know if it would have produced rain anyway,” says Alan Robock of Rutgers University.
Israel, a pioneer in cloud seeding, suspended its program in 2021 after 50 years because it appeared to deliver only marginal gains. “It wasn’t economically efficient,” says Pinhas Alpert, professor emeritus at Tel Aviv University.
Despite the difficulties in collecting data, the Center in the Emirates argues that the methods are generating an increase of at least 5% in annual precipitation – but recognizes the need for data that cover more years to satisfy the scientific community.
