# The Buying Time Argument within the Solar Radiation Management Discourse
## 4 A Case Study of a BTA Instance
As Figure 2 shows, the point in time at which temperature reaches a certain degree above pre-industrial level is delayed for several years, if SAI is used to limit the rate of temperature change. Using a different approach, the authors determine the amount of SAI in accordance with a steady warming rate of 0.1 \({}^{\circ}\)C per decade (instead of cutting warming rate in half, as in [39]). For RCP4.5, the length of required SAI deployment would have to be 160 years, if SAI is used to limit temperature change to 0.1 \({}^{\circ}\)C per decade, as Figures 3 and 4 show. For other RCPs, Figure 5 indicates the required timeframe and intensity of SAI schemes for varying temperature goals. If SAI is used to constrain temperature rise to 0.0 \({}^{\circ}\)C, that is to maintain current temperature, for all RCPs but RCP2.6, the finitude of the CE scheme is not given at all. \"It is important to repeat that SAI in this scenario would not be used to tackle absolute temperature change: (...) it [temporary SRM deployment, FN/KO] would not address problems such as temperature-dependent tipping point thresholds\" [38] (p. 2). SAI would only account for reducing the rate of change for a given temperature rise, not its magnitude. In this setup, abatement remains the main driver to limit global temperature rise. Accordingly, it is only emission abatement which could possibly lead to the stabilization of global mean temperature at well below 2 \({}^{\circ}\)C above pre-industrial level. Thus, the supplementary requirement has been adopted. This scenario does not frame SAI as a substitute for abatement, since both SAI and abatement are concerned with different aspects of global climate change. While the former addresses the rate of change, the latter influences its quantity. The absolute temperature change is still determined by abatement efforts, and SAI would be used only supplementary and temporarily to reduce the rate at which this change is to come about. As introduced above, there are primary and secondary climate goals, and this scenario clearly frames SAI for the secondary purpose of reducing the rate of change in order to reduce pressure. In this scenario, SAI does not reduce the dire need for drastic emission cuts--it instead points out what additional help SAI could generate. This is a great advantage of the scenario, since it does not run afoul of being a \"cheap techno-fix\" or posing a dilemma fo future generations [40]. Moreover, the no-impediment requirement becomes at least plausible in this scenario. If, moreover, a mitigation pathway like the RCP2.6 is assumed, the well below 2 \({}^{\circ}\)C target might be reached with abatement efforts only, while SAI would primarily address the secondary climate goal of reducing adaptation pressure. This shift of the BTA to the realm of adaptation is not trivial. Figure 2: The top panel (**a**) shows the total radiative forcing for RCP4.5, and a radiative forcing profile in which the rate of change is halved. The second panel (**b**) indicates the suggested SAI (SRM) profile. The effect on global mean temperature is shown in the third panel (**c**), indicating the time benefit, and the corresponding injection rates per decade are shown in the last panel (**d**) (source: [39]). Figure 4: Comparison of the solar reductions required to maintain a 0.1-\({}^{\circ}\)C per-decade rate of temperature change for different emission pathways (source: [38]). Figure 3: The top panel (**a**) shows SAI (SRM) being used for either maintaining constant global mean temperature (0 \({}^{\circ}\)C per decade) starting in 2020 or limiting the rate of change to 0.1 \({}^{\circ}\)C per decade for an RCP4.5 pathway. Panel (**b**) shows the corresponding solar reduction potential of SRM as well as the length of time over which SAI (SRM) would have to be deployed (source: [38], online version in color). To summarize this section, there are plausible instantiations of BTA, fulfilling some of the stated requirements.