The UK is preparing to approve outdoor solar geoengineering trials aimed at reflecting sunlight away from Earth in a controversial effort to counteract global warming. These experiments, set to begin within weeks, mark a significant move toward the potential use of solar radiation management (SRM) technologies.
The initiative, led by the government’s Advanced Research and Invention Agency (ARIA), has allocated £50 million for research and development. The planned activities include controlled field experiments involving cloud brightening and aerosol injection, techniques designed to increase the Earth’s reflectivity and reduce solar heating.
Among the proposed approaches are:
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Stratospheric Aerosol Injection (SAI): Involves dispersing fine particles, such as sulphur dioxide, into the upper atmosphere to reflect sunlight.
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Marine Cloud Brightening: Utilizes sea-salt particles sprayed into the atmosphere to enhance the reflectivity of clouds, a method inspired by observations of ship emissions leading to brighter cloud formations.
These methods are modeled after natural phenomena, such as volcanic eruptions and industrial emissions from shipping routes, which have been observed to cause temporary cooling effects.
Professor Mark Symes, ARIA’s programme director, confirmed that all tests will be limited in scale and duration, with stringent requirements to ensure reversibility and environmental safety. No toxic substances will be released.
In addition to physical trials, funding will support climate modeling, indoor simulations, public opinion research, and climate monitoring to assess broader impacts.
While the concept of solar geoengineering is gaining traction, it is not without criticism. Experts have warned that such interventions could trigger unpredictable weather patterns, such as droughts or cyclones, and disrupt regional climates.
A notable study by Rutgers University in 2018 highlighted the potential dangers of halting a geoengineering program abruptly, suggesting it could cause rapid and extreme global warming—up to ten times faster than typical climate change trends. This raises concerns about the reliability and governance of long-term geoengineering efforts.
