The French National Assembly was confronted with a demand this week to have the clouds in our skies protected by Unesco. The move comes amid concerns that weather systems could be scientifically manipulated for military or civilian use.
Who owns the clouds? A group of high school students, fearing the potential weaponisation of weather systems, put this question to the French parliament.
They were accompanied by French author and lawyer Mathieu Simonet who, in his book The End of Clouds, argues they are a precious natural resource in need of protection.
"Since the 1940s, experiments have been carried out on clouds in around 50 countries with the aim of manipulating the climate," Simonet told French daily Le Parisien.
The technique consists of injecting silver iodide or other substances into clouds from aeroplanes or canons on the ground, producing crystals of ice, Laurent Deguillaume, a physician at Clermont-Auvergne University, explained.
"They absorb humidity and turn into snow, ice or rain," he added.
Another technique involves injecting salt into clouds at high altitudes so water particles grow and are released faster.
"The impact of these experiments is not yet well documented, and the idea could lead to exacerbating tensions between states," Simonet warned.
He cited the 2018 example of an Iranian general who accused Israel of "stealing clouds". The cliam was quickly refuted.
War tactics
There was also "Operation Popeye", run by the Americans during the Vietnam War.
Between 1967 and 1972, the US carried out cloud seeding over the Ho Chi Minh Trail. They caused floods that disrupted North Vietnamese military supplies by causing landslides.
The tactic created a scandal that resulted in a UN convention banning the "weaponisation of clouds".
France was not a signatory.
Rosa, a 15-year-old student from a school in a suburb near Paris, asked: "Who owns the clouds if they don’t belong to the Earth?"
"At first I wasn’t concerned about this subject, but then I realised it could be dangerous to have experiments going on," she told Le Parisien.
"We have no real understanding of the effects this may have on military operations or the climate."
Harmful consequences
As droughts worsen with global warming, more countries are turning to cloud seeding.
"If everyone starts bombing the atmosphere with silver iodide, then it will undoubtedly have harmful consequences due to the stocking of chemicals in the ground," Deguillaume warned.
China, meanwhile, has invested more than a billion dollars into research. In 2022 Chinese authorities bombed the atmosphere to provoke rainfall over the Yangtze River to counter a historical drought, Simonet said.
Other Southeast Asian nations, like Indonesia, have turned to the technology to combat forest fires and smog.
Geoengineering has evolved considerably since World War II.
"In the last five years there has been a sharp increase in the number of countries using cloud seeding and the techniques are evolving quickly," Simonet told RFI.
Last year saw 70 projects linked to environmental manipulation, many focused on clouds and solar energy.
The United Arab Emirates regularly uses cloud seeding techniques. In Dubai, drones are sent into the clouds to set off electric shocks to force rainfall.
But many scientists agree that when it comes to consequences there is much uncertainty.
Climatologist and member of the International Panel on Climate Change Robert Vautard said that allowing "apprentice wizards" to experiment sets a dangerous precedent.
Large quantities of chemicals would need to be used over two decades before visible effects could be measured. In the meantime, we can't see the full impact on clouds, rainfall cycles and carbon emissions, Vautard said.
Petition
More than 450 scientists and climate experts signed a petition in 2022 against geoengineering experiments of this kind, citing the "risks of uncontrollable side effects".
Even if outright bans might not be possible, Simonet said, at the very least there should be best practice rules with future procedures documented and monitored by the scientific community.
He suggested that a parliamentary inquiry be launched in France to address the issue.
Gaëtan de Royer, the president of Koz, a consulting firm for public affairs supporting Simonet, said the request to Unesco makes sense.
"Our dream is that the Declaration of Human Rights will be revisited to include the rights of nature," he told Le Parisien.
"By asking MPs to consider jurisdiction for the protection of the sky, we’re asking them an offbeat albeit serious question: doesn’t this cause deserve support seeing as the clouds are shared by all of humanity?"
