Fact-checking claims about the UK's geoengineering experiments

Euronews

12-05-2025

Misinformation is circulating online after a recent announcement that the UK government is going to fund outdoor geoengineering experiments.
Geoengineering refers to deliberate, large-scale interventions in the Earth's environment to try to stave off the effects of climate change. It takes two main forms: solar radiation management (SRM), where a small portion of sunlight and heat is reflected back into space to cool the Earth, and carbon dioxide removal.
The UK is focusing on the former, with the government allocating some £56.8 million (€67 million) to the project, according to reports. The experiments will work with sun-reflecting particles in the stratosphere and spraying seawater on reflective clouds.
The Advanced Research and Invention Agency (Aria), which is backing the plan, has said that the tests will be small in scale, and that they will also look into how geoengineering could be governed internationally.
It's believed that if geoengineering proves to be safe, it could be used to cool the planet and slow global warming, giving more time to tackle the climate crisis.
Yet despite assertions that the UK's plans are in the experimental stage, they haven't stopped social media users from claiming that the country has already been engaging in geoengineering for years without public consent as a way to control the population.
The claims also feed into the widely debunked "chemtrails" conspiracy theory, whose believers insists that some vapour trails from planes contain harmful chemicals that are sprayed over the public around Europe or that others are being used to dim the sun and block out the light.
EuroVerify put these notions to experts, who resoundingly rejected them.
"It would be impossible to conduct large-scale weather modification experiments in secret. It just can't be done," said Jim Franke, researcher at the University of Chicago's geophysical sciences department.
"The amount of aircraft needed to fly this material to where it needs to go, and the radiative effect, would be easily obtainable by publicly available information," he added.
Wolfgang Cramer, professor of global ecology and researcher at CNRS, the French National Centre for Scientific Research, said that while there is plenty of valid criticism of geoengineering, it's disingenuous to accuse governments of looking into it with malicious intent.
"I am sure that governments such as the UK and others have an honest purpose, that there's a real wish to solve one problem of humanity," he told EuroVerify. "I think there's a debate about this,* and there are not necessarily bad guys and good guys."
They also refuted assertions that the UK's geoengineering experiment announcement is a cover for the fact that it and other countries have already conducted SRM in secret for years.
"That's complete nonsense, there's absolutely no evidence for that," Cramer said, noting that people should be careful not to confuse SRM experiments with cloud seeding techniques used in some parts of the world to increase precipitation and produce rain.
"That's not what I'm talking about when I talk about solar radiation management, because solar radiation in this definition is the long-term manipulation of the radiation balance of the atmosphere," he added.
Franke made a similar point, noting that some isolated, small-scale experiments have been carried out in the past, in addition to geoengineering computer simulations, but ultimately it's unreasonable to think that governments could have been carrying out such wide-ranging procedures for so long.
"Papers get published [by reputable universities] about geoengineering, so I'm sure that trickles into the online spheres and is misinterpreted in whatever way people interpret those things," he said. "There's material being generated which can be fed into this kind of conspiracy."
The international community's generally sluggish attempts to slash greenhouse gas emissions have sparked widespread frustration and prompted many to turn to geoengineering in search of a weapon against global warming.
However, the scientific community is divided on the technology's merits, in part due to the perception that it would divert resources away from tackling the root cause of climate change and reduce motivation to decarbonise, and also partly due to questions about how such schemes would be governed internationally.
"Technically and financially, [SRM] would be possible," said Cramer. "It would require a fleet of aircraft positioned around the planet in critical places that would basically fly day and night and inject the particles into the atmosphere."
"You could, based on model calculations, reduce global mean temperature a little bit by doing so," he said.
However, he added that his main concerns about SRM geoengineering are how long it would all take to come into effect, how much different parts of the world would benefit from it, and how it would be overseen.
"It will probably take a decade or so before you can even see the effects," he said. "And some areas would see more warming, others would see a lot less, maybe even to the point where they wouldn't even be happy about it."
"You will clearly have winners and losers ... The atmosphere is a highly dynamic structure, and if you want to control the amount of radiation that goes through it at every point in time and every point of space, due to the chaotic nature of the atmosphere, this cannot be done."
Experts say that a global SRM scheme would require an international body to govern its implementation, leaving it vulnerable to the political whims of the day. Any given country could in theory decide to withdraw at any point, thus harming the initiative and undoing any progress made.
The body would also potentially have to last for decades or even centuries until global temperatures had been sufficiently reduced and SRM slowly phased out, requiring significant financial and technical resources.
On the unwanted environmental effects, meanwhile, Franke said that SRM geoengineering could provoke a slowdown of the hydrological cycle.
"If you reduce incoming solar radiation a little bit, you will reduce evaporation and the atmospheric transport of water vapour and then the corresponding precipitation," he said. "So this general slowdown of the hydrological cycle could have regional impacts as far as reduced rainfall in some regions."
He added that pending further research, the extent and magnitude of this is still highly uncertain, and so whether or not solar geoengineering is beneficial in terms of water availability to people and plants across the globe is an open question.*
Other side effects, such as harming photosynthesis in plants due to a reduction in sunlight, have also been raised as a potential issue, but they are not well understood and are precisely why further research and experiments are needed.
Nevertheless, computer modelling so far does show that a moderate amount of SRM "would reduce almost all key climate hazards", Franke said.
"Pick whichever climate hazard is most relevant to your area: extreme wet-bulb temperatures in the summertime; some sort of coastal erosion driven by sea level rise; snowpack; ice sheet melting," he said. "Whichever it is, for pretty much all of them, solar geoengineering moderates that climate hazard."
"I am pro-researching geoengineering, I'm not pro-implementing geoengineering," Franke added. "The decision to do this has to be made by some international coalition of governing bodies, and using hopefully the best available research to do so."
Thousands of people took part Sunday in the solemn ceremony commemorating the 80th anniversary of the liberation of the Mauthausen concentration camp, an event that has been held annually since 1946 on the initiative of the survivors and their associations.
The slave labour camp in upper Austria was known for its extremely harsh conditions, considered to be even more severe than in other Nazi German death camps. It held nearly 190,000 prisoners during World War II, half of whom did not survive.
Those who died in the camp must not be forgotten, as the organisers of the event insisted.
"Nothing can be erased. Neither the transports, nor the forced labour, imprisonment, barracks, illness, cold, lack of sleep, hunger, humiliation, degradation, beatings, screams. Nothing can, nothing must be forgotten," said Guy Dockendorf, president of the International Mauthausen Committee (CIM).
Austrian President Alexander van der Bellen and several members of the Austrian government, including Chancellor Stocker, Vice Chancellor Babler and Foreign Minister Meinl-Reisinger, were in attendance.
Many high-ranking international guests, including the king and queen of Spain, attended the ceremony.
The concentration camp — which targeted Jewish and Romani people, socialists, anarchists and homosexuals, but also others who posed a threat to the Nazi regime — mostly consisted of inmates from Austria, Germany, Czechoslovakia and Poland, as well as Spanish Republican fighters and Yugoslav partisans, majority of which were deported from today's Slovenia and Serbia.
The event, organised by the Mauthausen Committee Austria, the successor of the Austrian Mauthausen Survivors' Association, brought together international representatives to honour the memory of the victims and renew the commitment to the values of freedom, human dignity and mutual respect.
The first official commemoration in Mauthausen — the last Nazi concentration camp to be liberated — took place in 1946, barely a year after liberation.
More than 10,000 people gathered at the foot of the "Todesstiege" ("Death Stairs") in the camp's quarry. On that occasion, the national delegates signed an official document stating that this commemoration would be held annually.
For decades, the commemoration ceremonies were mainly a matter for the survivors, always maintaining an international character but with little impact on Austrian society.
Over time, the Austrian Mauthausen Committee has taken over the event's organisation in cooperation with the International Mauthausen Committee and the Austrian Lagermeinschaft Association, with public financial support and, to a greater extent, private donations.