OPINION:China has a government office to meddle with Mother Nature called the Beijing Weather Modification Office, a name Orwell would be proud of, writes CLIFFORD COONAN

IT WAS like a hole in the sky, as the clouds dissipated to reveal bright blue sky over Tiananmen Square. Gradually the clouds disappeared completely, as if blasted away, and blazing sun shone down on the Red Detachment of Women in their mini-skirts and white jackboots as they marched past the Forbidden City to mark 60 years of the People's Republic of China.

A few short weeks later, Beijingers woke up on a Saturday morning in early November to see a winter wonderland, as snow blanketed the ground. The snowfall was months earlier than usual, almost as if it had fallen on government orders. Let it snow.

It appears the Chinese are becoming masters at cloud seeding, a process of launching chemicals into the atmosphere to cause water vapour in the air to crystallise at temperatures it otherwise would not, bringing about rain or snow or simply clearing fog. So have the Chinese innovated a process that can reliably produce weather on demand? Hard to say, but they certainly take making the weather seriously.

China has a government office to meddle with Mother Nature called the Beijing Weather Modification Office, a name Orwell would be proud of. This department employs 40,000 people, 3,000 of whom work with an arsenal of 7,000 cannon and 4,687 rocket launchers.

Ensuring the right weather was deemed essential for the 60th anniversary celebrations on National Day. Literally, nothing could rain on the parade - a showcase of China's military strength up Chang'an Avenue at the city's heart.

The snowfall was induced early in the year to help alleviate a long-term drought blighting the capital and most of the rest of northern China. In the event, more than 16 million tons of snow fell on the city, causing havoc with the power grid, stopping people from going to work as traffic snarled up and delaying hundreds of flights at Beijing Capital International Airport. People were furious, more at not being told than at the seeding itself.

And there was the fortuitous weather for the Olympic Games last year. The weather makers fired 1,110 rockets from artillery emplacements all around the city into the evening sky to make sure the opening ceremony was precipitation-free, and to disperse pollution in the capital.

The authorities claim the credit for this, although meteorologists still debate the effectiveness of cloud seeding. Most agree the principle is sound but are wary about judging the impact. Some studies show cloud seeding can increase precipitation by up to 30 per cent, but others worry about the effect on the environment.

Cloud seeding sounds like an invention from science fiction in the 1950s and, indeed, the technology behind it was developed in the 1940s. One of the earliest pioneers of cloud seeding was the atmospheric scientist Bernard Vonnegut, brother of the novelist Kurt. King Bhumipol Adulyadej of Thailand, a trained scientist, also has a patent for a method of cloud seeding.

The basic science sounds simple. Particles are injected into a cloud and act as freezing nuclei. Cloud droplets stick to the injected particles and fall as rain or snow. The key is getting the right sort of clouds.

The earliest attempts at cloud seeding involved dropping crushed dry ice, or carbon dioxide, pellets into the top of a cloud from an aircraft. Later, scientists started to use silver iodide because it was a better agent. Liquid propane is also used in some countries.

The silver iodide is fired at the clouds using aircraft or artillery batteries. To make it snow in early November this year, for example, the Beijing Weather Modification Office fired 186 canisters of silver iodide into the clouds. This after more than 100 days without rain. It was the earliest first snow in 22 years in Beijing.

It's not just China. In the United States, there are occasional rows between neighbouring states over who "owns" the rain produced by clouds. Soviet Russia seeded clouds to make sure the sky was clear for their famous May Day parades, and the mayor of Moscow does the same thing today.

But no other country seems to go about weather modification in such a sustained way as China. Some citizens are worried about the environmental impact, especially because of rumours in the city that rain-bringing agents killed 10,000 trees in 2005. However, Zhang Qiang, the deputy director of the Beijing Weather Modification Office, went on record around the time of the Olympics insisting there was no environmental danger from using silver iodide to disperse rain and clouds, as only one gram of the chemical was released per square kilometre, a level safe for humans.

Environmental fears aside, I say damn the begrudgers. I'm going to call the Beijing Weather Modification Office to order a white Christmas.