Whether it is the Chinese firing weapons into the sky to make it rain, or the Thai government setting up a "royal rainmaking project", the science of weather modification has always had a touch of the sci-fi about it.
So it is perhaps little surprise that the effectiveness of such an eccentric area of research has always been a little foggy. Indeed, no matter how hard you try – say, through launching silver-iodide particles into clouds to make them rain – it's hard to tell how influential you're actually being as it might have happened anyway.
But now, one of the world's leading weather experts thinks that the wind surrounding weather modification is set to change.
Roelof Bruintjes, of the National Center for Atmospheric Research in Colorado, USA, believes that weather-monitoring technology is so hot nowadays that science fiction may soon become science fact.
Speaking earlier this week, he said: "Now we can measure clouds so well – even from the inside – we can get many more answers as to what the effects of man-made intervention are, and separate them from what would have happened naturally.
"For the first time, we can discover whether humans have changed weather patterns. It's a whole new opportunity. We are at the most exciting time for weather modification in its history."
Many of the world's driest nations have dabbled in weather modification since its first major lab breakthrough in 1949, when researchers at General Electric in New York discovered that silver-iodide smoke caused the kind of droplets in clouds to turn to ice, a process vital to rain formation.
Since then, however, experts came to the conclusion that the processes involved in rain formation were just too complex.
But that hasn't stopped many governments from trying. There are currently 150 weather-modification projects taking place in more than 40 countries. In many of these, researchers are using trials in which some randomly chosen clouds are "seeded" while others are not, and both groups are monitored.
Arlen Huggins of the Desert Research Institute in Nevada, USA, is leading one of these studies in Australia's Snowy Mountains, where the snow pack has shrunk in recent decades. Reportedly, their results to date might suggest that seeding works (although there are still two years of the six-year project left to go).
The most extensive operations are taking place in China, however. Here, for example, weather-modification "authorities" use conventional military weaponry to bombard clouds with silver-iodide particles. Under the guidance of the China Meteorological Administration (CMA), local "weather changing" offices employ some 39,000 staff equipped with 7,113 anti-aircraft cannons, which, in 2006, were used to fire a million rounds of silver iodide into the atmosphere (with the country spending over $100 million (Dh375m) a year in the process).
The Chinese state news agency claims that between 1999 and 2006, China produced 250 billion metric tonnes of artificial rain, though researchers take this with a pinch of salt. In the United Kingdom, Philip Brown, the Met Office's cloud-physics research manager, says: "There have been many experiments in the US; Israel had a programme for a long time; and more recently, South Africa has done a lot of work.
"I know it has been done in Switzerland and France, promoted in part by insurance interests, to reduce damaging hail. The firms, which I'm sure part-funded operations, were looking to decrease insurance losses on crop damage. Russia has a semi-operation set up to do cloud seeding, too."
So, what is prompting these gargantuan efforts? Brown explains: "On the one hand, it's the scientific intrigue of trying to understand what makes clouds rain. And then there is the sometimes much more powerful economic imperative. Clearly there are a lot of regions suffering – such as Australia recently – with drought.
"People will try anything to avoid such things, even if the scientific signs supporting it are a little weak.
"The potential economic value outweighs the scientific values. Making it rain where it wouldn't otherwise might allow you to keep agriculture going."
The Chinese have gone public with their intention to stop drizzle ruining the opening ceremony of the 2008 Olympics. The government's concern is that, during the summer, there is a 50 per cent chance of rain.
It has announced that "action units" will "stand alert" upwind of the city, ready to wring the clouds dry before they can drift over any stadium.
The initial response of some scientists – to pour scorn on such proposals – may have been woefully misplaced, however, as for the first time, experts may be able to see if the weather is affected by such schemes.
Bruintjes says: "We have seen that 'changing clouds' does work in certain circumstances. But these often have to happen naturally, and we have to be able to detect those conditions ahead of time.
"However, our models are getting better and better at predicting this."
His comments, likely to cause controversy, prompt the question: how much money would have been saved if the flooding in Britain last year (which cost the economy over £2bn) could have been avoided?
And how many lives could have been saved (at least 1,300) in and around New Orleans if 2005's Hurricane Katrina could have been averted? Such issues will become increasingly pressing across the developing world as the climate changes.
But some weather-watchers are concerned that weather alteration will lead to accusations that governments are "playing God".
These are huge issues for the world's economy, and companies may believe that, even if it does prove costly to create a dry Wimbledon, say, or a rainy crop season, it will be worth the effort.
Wacky weather technologies will doubtless be fizzing into the sky for another few decades yet. (The Independent)
In February, Joe Golden, of the US Department of Homeland Security, organised a meeting on hurricane modification. His ultimate aim? To look into how researchers can banish these devastating tempests from American skies for ever. "It's time for a fresh look at hurricane modification," he said.
BRING ON RAIN
A torrent of US-based schemes (and others worldwide) have tried to tinker with the magic behind rain creation. They include the "Western Kansas Weather Modification Program", which is trying to cut the size of hail or boost rainfall and snow.
MAKE THE SUN SHINE
According to Russian media reports, that nation's military has announced that up to 12 aircraft will "disperse clouds" to "ensure good weather" over Red Square during Victory Day celebrations in Moscow early next month. Last year, the Russian Air Force claimed to have nixed cloud formations by spraying them with potent concoctions including dry ice, silver iodide and cement powder.
Ahead of this summer's Beijing Olympics, the Chinese government hopes to provoke showers, by injecting chemicals into clouds, to "wash away pollutants". The massive drive to reduce smog also includes the planting of a forest twice the size of New York's Central Park on a 1,750-acre site north of the Olympic village, to raise oxygen levels.