The UK government's Advanced Research and Invention Agency (Aria) is funding real-world geoengineering experiments to test methods of blocking sunlight and slowing the climate crisis. The £56.8 million programme includes trials of sun-reflecting particles in the stratosphere, brightening clouds with seawater sprays, and pumping water onto sea ice to thicken it.
Aria says the experiments are vital to gather “critical missing scientific data” as the Earth nears several catastrophic climate tipping points. If proven safe, geoengineering could temporarily cool the planet, buying time to address the root cause of climate change: fossil fuel burning.
The projects will be small-scale and rigorously assessed before deployment. They include releasing non-toxic mineral dust from a weather balloon in the stratosphere, seeding clouds over the Great Barrier Reef and UK coast, and thickening sea ice in Canada. Modelling and international governance research are also part of the programme.
Critics, including Prof Raymond Pierrehumbert of Oxford University and Mary Church of the Center for International Environmental Law, warn that solar geoengineering is unpredictable and risks normalising dangerous technologies. They argue it distracts from cutting emissions and lacks governance.
Aria’s CEO Ilan Gur defended the research, saying it is essential to understand whether cooling approaches could be used safely. Prof Mark Symes, programme director, stressed that decarbonisation remains the priority, but with current trajectories threatening tipping points, exploring emergency options is prudent.
