Kate Mackenzie Modify your weather, here

China Daily reports that the country’s Weather Modification Office says there is ‘rising demand’ for ways to control the weather:

As drought and hailstorms pose severe threats to rural income and food supply, there is a rising demand for technology to cushion the impact, Zheng Guoguang told China Daily.

What is weather modification, you ask? Well, it’s mostly cloud-seeding, and, in China at least, precipitating snowfall and preventing hail.

China is a big proponent of weather modification, and claimed success with the technology at the Beijing Olympics opening and closing ceremonies, among other events.

Furthermore, It’s also spending a fair bit on these efforts, says China Daily:

Last year, officials used artillery, rockets or planes to induce precipitation for wheat-producing areas and some other regions, thanks partly to a central government fund of 60 million yuan ($8.8 million), Zheng said. In the past, most funds for weather modification projects came from local governments.

In all, a record 840 flights were made to increase rain last year for areas spanning 3.6 million square kilometers – or roughly one-third of China’s territory. Also, at least 116,000 rockets and 890,000 artillery shells were fired to alter atmospheric phenomena.

Nationwide, weather modification projects cost 910 million yuan in 2009, but helped generate output 30 times that amount, according to statistics from the Weather Modification Center.

The difficulty is knowing whether it actually worked: perhaps it would have rained or snowed anyway? As for preventing hail, well that is especially difficult to prove. The US for 20 years investigated ways to modify hurricanes through seeding with silver iodide, but gave it up in the early 1980s.

Weather modification is somewhat marginal in mainstream science, although Nature in 2008 called for more research into the technologies, in an editorial that acknowledged the patchy history of the field.

For more on China’s efforts in particular, Vanity Fair ran an interesting story on the subject in 2008:

So deep is the Chinese faith in weather modification that the claims of success are apparently accepted without question. It’s a minor thing. Who cares? But again, the methods of measurement are unclear. How does one distinguish between artificial and natural rain—between rain induced to fall and what would have fallen anyway? In Beijing last winter I spoke with atmospheric scientists at the C.M.A., who acknowledged the difficulty and excused the official claims as the sort of assertions necessary to motivate operators in the field. Rainmaking is uncomfortable work, poorly paid, and unusually exposed to the weather. The scientists themselves have a better deal. They are paid well enough to buy new cars, and are trained to accept uncertainty. As loyal Chinese government employees, they believe in the existence of progress even if it cannot be measured.

Then there’s the pollution. While the China Daily story asserts that the Weather Modification Office monitors silver ions in local drinking water, this report isn’t particularly reassuring.