UK scientists are set to conduct outdoor geoengineering experiments as part of a £50 million government-funded programme, the Advanced Research and Invention Agency (Aria) has announced. The small-scale trials will be rigorously assessed to provide critical data on the potential of technologies that could temporarily slow climate change by blocking sunlight.
The programme, along with an additional £11 million project, positions the UK as one of the world's largest funders of geoengineering research. However, the field remains highly controversial, with previous outdoor experiments cancelled due to strong opposition. Most proposals aim to reflect sunlight away from Earth, for example by releasing reflective particles into the atmosphere or using seawater sprays to brighten clouds.
Proponents argue that solar geoengineering could offer a temporary brake on rising temperatures, buying time for deep cuts in carbon emissions. Given the failure to halt emissions and recent record hot years, research is deemed vital. But critics warn of unintended consequences, such as disrupting rainfall patterns, and say it could distract from tackling the root cause of climate change—fossil fuel burning.
Prof Mark Symes, leading the Aria programme, cited the threat of climate tipping points as a strong reason to research solar geoengineering. 'The uncomfortable truth is that our current warming trajectory makes a number of such tipping points distinctly possible over the next century,' he said. 'Having spoken to hundreds of researchers, we reached the conclusion that a critical missing part of our understanding was real world, physical data.'
Symes confirmed no toxic substances would be released, and environmental impact assessments and community consultations would precede any outdoor experiments. Details of funded projects are expected in weeks. Meanwhile, a separate £10 million programme by the National Environment Research Council will use computer modelling and natural analogues to study solar geoengineering without new outdoor trials.
Global funding for geoengineering remains relatively small, but the UK could become the leading funder as US research faces cuts under President Trump. Experts stress that geoengineering is not a substitute for emission cuts, and there is no international agreement governing large-scale schemes.
