Can reflecting the sun save the planet?

The UN secretary-general says that humanity is on a “fast track to climate disaster” if we continue along our current path of rising greenhouse gas emissions. One possible method to avoid a deadly increase in global temperature—one of the planet’s vital signs that measures the human contribution toward the climate crisis—would be to reflect some of the sun’s energy back into space, effectively blocking out some of the sun’s rays. Solar climate intervention, or solar geoengineering, is a controversial idea that critics say would harm the fight to save the planet. Supporters say that our current strategies seem to be failing, and that we have to consider other approaches.

This conversation between Sir David King and Jennie C. Stephens took place on Twitter Spaces on November 9, 2022, and was hosted by Nelufar Hedayat.