Abstract
We review the capabilities and costs of various lofting methods intended to deliver sulfates into the lower stratosphere. We lay out a future solar geoengineering deployment scenario of halving the increase in anthropogenic radiative forcing beginning 15 years hence, by deploying material to altitudes as high as ∼20 km. After surveying an exhaustive list of potential deployment techniques, we settle upon an aircraft-based delivery system. Unlike the one prior comprehensive study on the topic (McClellan et al 2012 Environ. Res. Lett. 7 034019), we conclude that no existing aircraft design—even with extensive modifications—can reasonably fulfill this mission. However, we also conclude that developing a new, purpose-built high-altitude tanker with substantial payload capabilities would neither be technologically difficult nor prohibitively expensive. We calculate early-year costs of ∼$1500 ton−1 of material deployed, resulting in average costs of ∼$2.25 billion yr−1 over the first 15 years of deployment. We further calculate the number of flights at ∼4000 in year one, linearly increasing by ∼4000 yr−1. We conclude by arguing that, while cheap, such an aircraft-based program would unlikely be a secret, given the need for thousands of flights annually by airliner-sized aircraft operating from an international array of bases.
Highlights
Solar geoengineering is commonly seen to be subject to what some call its ‘incredible economics’ (Barrett 2008) and, its ‘free driver’ effect: its direct costs are so cheap compared to its potential climate impacts so as to reverse many of the properties of the so-called ‘free rider’ problem governing carbon mitigation decisions and climate policy more broadly (Wagner and Weitzman 2012, 2015, Weitzman 2015)
Like McClellan et al (2010, 2012), and later reviewed by Moriyama et al (2017), we explore an array of different Stratospheric Aerosol Injection (SAI) lofting technologies and given our more specific mission criteria, we conclude that aircraft are the only reasonable option
We propose such a plane and call it SAI Lofter (SAIL), describing its basic specifications and providing detailed cost estimates for its design, manufacture, and operation under a hypothesized solar geoengineering scenario of halving the increase in radiative forcing from a date 15 years
Summary
Solar geoengineering is commonly seen to be subject to what some call its ‘incredible economics’ (Barrett 2008) and, its ‘free driver’ effect: its direct costs are so cheap compared to its potential climate impacts so as to reverse many of the properties of the so-called ‘free rider’ problem governing carbon mitigation decisions and climate policy more broadly (Wagner and Weitzman 2012, 2015, Weitzman 2015). The governance problem becomes one of cooperation to restrain rather than increase action We probe these economic assertions and review the capabilities and costs of various lofting methods intended to deploy sulfates into the lower stratosphere, the leading proposed method of solar geoengineering (Keith 2000, Crutzen 2006, National Research Council 2015). We further conclude that no other existing aircraft have the combination of altitude and payload capabilities required for the mission, leading us instead to the design of a new plane We propose such a plane and call it SAI Lofter (SAIL), describing its basic specifications and providing detailed cost estimates for its design, manufacture, and operation under a hypothesized solar geoengineering scenario of halving the increase in radiative forcing from a date 15 years . We instead hope to illuminate discussions of direct SAI deployment costs based on existing technologies, thereby facilitating further benefit-cost comparisons and grounding ‘free driver’ discussions in concrete numbers supported by science-based SAI deployment scenarios and sound aerospace engineering
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
