Responsible research for space-based climate geoengineering

Reflecting shortwave solar radiation away from the Earth could help to reduce the risks of overshooting 1.5°C of global warming. Terrestrial proposals for solar radiation modification, or geoengineering, have been the focus of most research, but suffer from the greater risks and uncertainties that arise from deliberate large-scale intervention inside Earth’s systems. Space-based geoengineering methods suggest relatively safer and more predictable possibilities by altering the solar constant outside of the Earth’s atmosphere. To determine the possible contributions of these methods to climate policy – and to other co-beneficial aspirations in outer space – there is a clear need to responsibly advance research. The key to this lies with accounting for societal values and interests in evaluating which methods to take forward (if any), and in developing appropriate governance arrangements. In this article I review what we know from the very limited societal evaluations of space-based geoengineering so far, identifying thematic concerns around risks, naturalness, governance, delay, feasibility, cost, benefits, and participation, and set out a range of future priorities for responsible research. I then examine the implications of these evaluations for space-based geoengineering governance, considering the roles of global research networks, precautionary regulations, high level principles, multilateral processes, and global engagement. I conclude by reflecting on the importance of framing effects in societal engagements with space-based geoengineering, before proposing a research agenda to broaden out and open them up.