A leading climate scientist says the CIA approached him to ask for information on how to disrupt the weather.
Professor Alan Robock said he received a call three years ago from two men wanting to know if experts would be able to spot a hostile force’s attempts to upset the US climate. However, he claimed the real intention was to find out how feasible it might be to secretly interfere with the climate of another country.
The professor, from Rutgers University, New Jersey, has investigated the potential risks and benefits of using stratospheric particles to simulate the climate-changing effects of volcanic eruptions.
He said: “I told them, after thinking a little bit, that we probably would because if you put enough material in the atmosphere to reflect sunlight we would be able to detect it and see the equipment that was putting it up there.”
So how feasible is it to control the weather?
Chinese research into weather control is said to date back to 1958. In 2008, the government-run weather modification programme hit the headlines when it was said to have controlled the climate ahead of the summer Olympic Games.
The Chinese government reportedly launched thousands of specially designed rockets into the sky in Beijing to stop it raining during the opening ceremony.
The programme is said to employ up to 35,000 people across China, who are paid to handle anti-aircraft guns and rocket launchers.
These weapons are said to fire pellets containing silver iodide into clouds. Silver iodide is thought to concentrate moisture and cause rain, a process known as cloud seeding.
The High Frequency Active Auroral Research (HAARP) was a little-known US military defence programme in Alaska.
Designed by BAE Advanced Technologies, its purpose was to analyse the ionosphere, a region of the upper atmosphere, with the aim of developing better radio communications technology.
HAARP was a target of conspiracy theorists, who said it was used for weather modification, to cause earthquakes, tsunamis and the disappearance of Flight MH370. In May 2014, the US Air Force notified congress that it would be closing down the programme.
The Russian government is said to have used rain prevention methods since Soviet times, seeding clouds three times a year during Victory Day, City Day and Russia Day.
Ahead of each public holiday, the Russian Air Force often dispatches up to 12 cargo planes carrying loads of silver iodide, liquid nitrogen and cement powder to seed clouds above Moscow and empty the skies of moisture.
However, in 2008, planes are said to have dropped a 55lb sack of cement on a suburban Moscow home by accident. Weather specialists said the cement’s failure to turn to powder was the first hiccup in 20 years.