Countries increasingly influence the weather. But to whom do the clouds belong?

Generating rain, dissolving fog or suppressing a hailstorm. Increasingly, countries are tinkering with the weather. But who legally owns a cloud?

For a while it looked like Elon Musk would grit his teeth over water. The newest Tesla factory, strategically planned in northern Mexico to take advantage of both low-wage and U.S. climate subsidies, met with objections from President López Obrador. “If there is no water, there will be no permit,” the president said in February. It was not infrastructure, available labor or the tax system that determined the business climate here, but something as basic as water.

The years of drought in northern and central Mexico are beginning to take on permanent features. The main water reservoir is at its lowest level ever, forcing the water pressure on taps in Mexico City to be lowered. It is forcing the president to take unorthodox measures, such as discouraging water-intensive investments. For example, he has already gotten a brewery to locate in the south. With Musk, he struck a deal: Tesla will reuse all the water it needs and thus will still be allowed to build its factory (a $5 billion investment).

Another stakeholder group, the farmers, desperately asked the government to “bomb the clouds. In March and April, the Air Force conducted dozens of flights over the northern states of Nuevo León and Baja California to disperse silver iodide in the clouds. Cloud seeding is called this, cloud seeding, to artificially generate rain.

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“Seeding clouds to systematically generate more rain is a rearguard action,” says Pier Siebesma, professor of clouds and precipitation at TU Delft and a researcher at KNMI. “The demonstrated precipitation increase is currently at most only about 10 percent. Many countries say they are hugely successful, but that is difficult to prove. On the other hand, Israel has stopped after decades of experimentation because the yield does not outweigh the cost.”

Therefore, for southern Europe, burdened by a particularly hot and dry spring and where water is so scarce that it leads to arrests of illegal avocado growers (Malaga) and premature forest fires (Pyrenees), cloud seeding is not a solution, Siebesma says. “It doesn’t produce enough. Besides, it’s often cloudless there. You need clouds that are on the verge of raining. These countries benefit much more from storing precipitation as much as possible once it falls.”

So still, there are countries that want to squeeze out of their clouds what is in them. China is the champion: in 2020, when, according to international media, 35,000 Chinese were already working on weather modification, the Communist Party announced it would increase the land area where cloud seeding is applied fivefold by 2025, to 5.5 million square kilometers, an area the size of one and a half times India.

That scale raises new questions. In India, for example, fears arose that Chinese plans could alter India’s monsoon rains. Rain theft, it is soon called. Professor Siebesma thinks this will not be too bad. “Most monsoon rain in India comes from the southwest, not from over the Himalayas,” he said.