Scientists agree that cutting carbon emissions as soon as possible is key to tackling global warming. But as emissions continue to rise, some are now calling for more research into measures that could be used alongside decarbonisation, including – controversially – what’s known as ‘solar geoengineering’ technologies. One idea being considered is spraying light-reflecting particles into the atmosphere to temporarily cool down the earth. It may sound far-fetched, but the idea is based on naturally observed effects following volcanic eruptions. Scientists are now asking whether we could mimic those effects to avoid the worst climate impacts. But research into this technology is not without opposition. A recent solar geoengineering experiment in Sweden got cancelled following a fierce backlash from indigenous and environmental groups. Many say tampering with the climate in this way is too risky to ever try in the real world. So how does solar geoengineering work? What are the risks? And will we ever have to use it? Contributors: Elizabeth Kolbert, staff writer at the New Yorker and author of Under a White Sky Asa Larrson-Blind, Vice-President of the Saami Council Raymond Pierrehumbert, Halley Professor of Physics at the University of Oxford David Keith, Professor of Applied Physics and Public Policy at Harvard University Presenters: Neal Razzell and Graihagh Jackson Producers: Zoe Gelber and Jordan Dunbar Series producer: Rosamund Jones Editor: Emma Rippon