Cities Fall Out Over Cloud

Chinese meteorologists are accusing each other of what could prove to be one of the defining crimes of the 21st century: rain theft.

The use of cloud-seeding guns, rockets and planes to induce rainfall has created tensions between drought-plagued regions, which are competing to squeeze more drops out of the sky than their equally arid neighbours.

With water resources of only 2,200 cubic metres a person a year - less than a quarter of the global average - China is one of the world's leading users of rain-making technology.

The technique usually involves dropping dry ice or silver iodide on cumulus clouds to induce or accelerate precipitation above reservoirs and rivers.

Planes are the most common method of delivery, but scientists have also experimented with anti-aircraft guns, rockets and weather balloons.

The municipal authorities in Beijing, which has suffered a drought for each of the past five years, were among the first to use this method to improve the city's water supplies. And the central government has set aside £30m for similar weather management systems to be adopted nationwide.

The technique is now so widespread that it is reportedly sparking rows between neighbouring areas.

"The practice has caused considerable controversy in recent days, with some saying that one area's success with rain has meant taking moisture meant for one place and giving it to another," China Daily reported yesterday.

The paper cited the case of central Henan province, where five arid cities are racing each other to induce precipitation. When clouds passed over the area last Saturday, Pingdingshan enjoyed a downpour of more than 100mm, but Zhoukou had to make do with less than 30mm. Meteorological officials in Zhoukou accused their counterparts in Pingdingshan of intercepting and overusing clouds.

Legal experts are now calling for the government to draft laws on cloud-farming, but scientists say the technology's effect is not yet clear enough to measure and regulate.