I would only be comfortable with deploying solar geoengineering - the idea of deliberately increasing the reflectivity of the planet, most likely by introducing aerosols into the stratosphere - on a scale large enough to alter the climate if three basic conditions were met:
- At least a decade of serious international, open-access, transparent, and collaborative scientific research, including multiple small-scale field experiments. And, crucially, it would only make sense to proceed if the results of that research showed that the technology was highly likely to be effective with relatively low risks.
- More vigorous action to cut global emissions. Ideally I would like to see solar geoengineering linked to robust mitigation, with deployment taking place only after global emissions were on a clear downward trajectory.
- A multinational (though not necessarily universal) agreement dealing with decision-making authority, risk management, compensation, etc. Such an agreement would need to reflect a broad though not universal political consensus among governments and major stakeholders, and would also need to be widely viewed as just and legitimate.
Bottom line: We need more research.
Other voices in the conversation:
- Janos Pasztor, climate policy expert and executive director, Carnegie Climate Geoengineering Governance Initiative: We aren't ready to engineer the climate
- David Dana, legal scholar, Northwestern University: Talking about geoengineering is distracting
- Jane Long, energy and climate scientist: It's time to investigate geoengineering technologies
- Matthew Watson, geoengineering researcher, University of Bristol: We need to be sure the geoengineering cure isn't worse than the disease