How China became fixated on cloud seeding

It all means the cost could often be outweighing the output, especially when using airborne methods. Ground-based methods, on the other hand, which rely on generators sending silver iodide or another trigger up into the clouds via air currents, are cheaper but far less predictable. "Airborne seeding is pretty efficient, but it's also very expensive, so that's why people do the ground-based seeding," says Friedrich.

It's also impossible to know what the outcome will be of wider, consistent climate modification, in China or elsewhere. "It is very difficult to assess, let alone predict, regional climate impacts and remote anomalies from weather modification operations," says Manon Simon, a lecturer at the University of Tasmania, who's done extensive research on the potential geopolitical implications of China's weather modification. It's particularly hard to know whether long-term programmes may result in more frequent or intense droughts or floods, says Simon. Ascertaining these risks, she adds, needs ongoing assessment and monitoring as well as extensive international cooperation.

In the almost 10 years since Snowie, seeding techniques and radar technologies have improved, which could mean more precipitation is being produced. As drone technology has improved in recent years, China in particular has increased the use of advanced drones and begun leaning on AI to improve the accuracy of silve r iodide drops. 

Both China and the United Arab Emirates are also experimenting with flare seeding and sending negative ion charges into clouds to help kickstart droplet bonding, which leads to precipitation.

And yet, just as with traditional cloud seeding, there remains a scarcity of independent research showing these new methods definitively produce more precipitation. Scientists now fear that rising droughts worldwide due to climate change will fuel uptake of cloud seeding technology, but not the research needed to show when and where it works cost effectively.