Beware the Toll Dodgers: defending the Tollgate Principles for governing solar geoengineering

Abstract The Tollgate Principles (‘TGPs’) aim to represent ‘the price that must be paid’ by anyone claiming to be ethically serious about pursuing solar geoengineering (Gardiner and Fragnière, Ethic Policy Environ 221(2):143–174, 2018). The TGPs are influential but, like other governance principles, have also provoked criticism. This paper clarifies the Tollgate approach by responding to objections and dissolving some perceived tensions. It argues that, while not the final word, the TGPs are an important step in the evolution of geoengineering governance and should continue to be taken seriously at all levels. It concludes that rather than “beware the Toll Keepers” (Briggle, Ethic Policy Environ 21(2):187–189, 2018) we should instead “beware the Toll Dodgers”: those who would brush aside the TGPs and other ethics-centered approaches. As well as defending the Tollgate approach specifically, the discussion provides broader lessons for governing geoengineering and other controversial technological interventions.