These questions highlight the difficulties we will have in making a decision on geoengineering.
What do we need to know? As much as we possibly can. A choice to try geoengineering will always involve comparing the risk of human-induced climate change to the risk of human-induced climate change plus geoengineering. The more we know, the more accurate we can be about those risks.
What choices we might have: Any choice to do a geoengineering experiment — be it a small study or a deployment that would modify world climate — should involve comparing the expected gains in knowledge or climate benefits to the risks of the action.
Bottom line: Cutting carbon emissions should be tried first and foremost. (The best way to solve a problem is not to have it!) But we also need to investigate which geoengineering technologies might best compliment those efforts. Geoengineering should be thought of as one strategic element in the tool box for dealing with climate change. It should never be invoked as a stand alone technology that obviates cleaning up our energy system.
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
- David Keith, climate and energy researcher, Harvard University: Solar geoengineering needs at least another decade of research
- Matthew Watson, geoengineering researcher, University of Bristol: We need to be sure the geoengineering cure isn't worse than the disease