Taking it outside: Exploring social opposition to 21 early-stage experiments in radical climate interventions

Large-scale and highly experimental interventions are being considered as strategies to address climate change. These include carbon dioxide removal approaches that are becoming a key pillar of post-Paris assessment and governance, as well as the more controversial suite of solar geoengineering methods. In this paper, we ask: Who defends and opposes these experiments, and why? After screening 44 early-stage experiments, we conduct a qualitative comparative analysis of 21 of them in five areas: ocean fertilization, marine cloud brightening, stratospheric aerosol injection, ice protection, and enhanced weathering. We develop a common framework of analysis, treating experiments as sites in which the risks and appropriate governance of early-stage science and technology are envisioned and disputed among scientists and other social groups. Our contribution is to map and explain the key issues of contention (why), actors (who), and tactics (how) that have shaped opposition across these linked fields of experimentation and technological development, from the 1990s till today. In doing so, we build upon and connect past studies on particular climate experiments and develop insights relevant to governance outlooks perceptions, discourses, and intents surrounding immature but potentially crucial climate technologies. •Systematically explores opposition to 21 radical climate interventions experiments.•An NGO alliance drives visible opposition, but intra-scientific contestation is rife.•Many experiment planners contest being labelled as researching ‘geoengineering’.•Co-benefits for eco-restoration or innovation are growing justifications.•Societal engagement is a growing motif in governance, but intent and rigor varies.