http://m.pnas.org/content/early/2016/05/04/1520795113.abstract
Estimating option values of solar radiation management assuming that climate sensitivity is uncertain Yosuke Arino et al Edited by M. Granger Morgan, Carnegie Mellon University, Pittsburgh, PA, and approved April 4, 2016 Significance Stratospheric sulfur injection is an unprecedented manipulation of climate systems to rapidly decrease the global mean temperature and could entail environmental risk as well as confront ethical and governance challenges. Nonetheless, most studies have only evaluated impacts of solar radiation management (SRM) on the premise of its deployment. This paper presents one possible methodology for estimating option values of SRM assuming a fairly moderate scenario on SRM’s use compared with preceding literature, which would be helpful to examine realistic values of SRM for the society where social acceptability of SRM’s actual deployment is not high. Our results emphasize the near- to mid-term role of retaining SRM as a later risk-hedging option in the face of the uncertainty about climate sensitivity. Abstract Although solar radiation management (SRM) might play a role as an emergency geoengineering measure, its potential risks remain uncertain, and hence there are ethical and governance issues in the face of SRM’s actual deployment. By using an integrated assessment model, we first present one possible methodology for evaluating the value arising from retaining an SRM option given the uncertainty of climate sensitivity, and also examine sensitivities of the option value to SRM’s side effects (damages). Reflecting the governance challenges on immediate SRM deployment, we assume scenarios in which SRM could only be deployed with a limited degree of cooling (0.5 °C) only after 2050, when climate sensitivity uncertainty is assumed to be resolved and only when the sensitivity is found to be high (T2x = 4 °C). We conduct a cost-effectiveness analysis with constraining temperature rise as the objective. The SRM option value is originated from its rapid cooling capability that would alleviate the mitigation requirement under climate sensitivity uncertainty and thereby reduce mitigation costs. According to our estimates, the option value during 1990–2049 for a +2.4 °C target (the lowest temperature target level for which there were feasible solutions in this model study) relative to preindustrial levels were in the range between $2.5 and $5.9 trillion, taking into account the maximum level of side effects shown in the existing literature. The result indicates that lower limits of the option values for temperature targets below +2.4 °C would be greater than $2.5 trillion. solar radiation management, option value, climate sensitivity, uncertainty, decision tree analysis -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/geoengineering. For more options, visit https://groups.google.com/d/optout.
