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This paper offers a preliminary and exploratory assessment of the potential benefits and costs of climate engineering (CE). We examine two families of CE technologies, solar radiation management (SRM) and air capture (AC), under three emissions control environments: no controls, optimal abatement, and limiting temperature change to 2°C. Our analysis suggests that, today, SRM offers larger net benefits than AC, but that both deserve to be investigated further. In the case of SRM, we investigate three specific technologies: the injection of aerosols into the stratosphere, the increase of marine cloud albedo, and the deployment of a space-based sunshade. We estimate direct benefit-cost (B/C) ratios of around 25 to 1 for aerosols and around 5000 to 1 for cloud albedo enhancement.
Technological progress might significantly lower direct cost estimates of stratospheric aerosols and thus raise the expected benefits. Yet, large uncertainties remain about the science and engineering of SRM. Only a substantial research program could resolve these uncertainties, but the very large potential net benefits of SRM offer strong prima facie evidence for including R&D on SRM as a part of any portfolio of climate policies during the next decade.
Therefore, we suggest that the Copenhagen Consensus allocate an average of approximately 0.3% of its $250 billion climate-change budget ($750 million per year) to SRM and AC research over the next decade. SRM is the higher priority, owing to its larger and more current net benefit potential. This research program should explicitly focus on identifying possible side effects, especially those which might imply non-trivial costs.
Lee Lane is a resident fellow at AEI and codirector of the AEI Geoengineering Project. J. Eric Bickel is an assistant professor in both the Operations Research/Industrial Engineering Group and the Department of Petroleum and Geosystems Engineering at the University of Texas at Austin.