# The Buying Time Argument within the Solar Radiation Management Discourse
## 2 Building Blocks of BTA
### BTA and the Costs of Abatement  
It is a crucial presupposition of BTA that transition to a global low-carbon society should happen anyway. The inevitable transition towards carbon-free production and consumption should arguably come at the lowest possible social and economic opportunity costs. This is part of the \"efficiency\" rationale that [PERSON] has provided [27]. [PERSON] et al. argue along the same line in favor of prudent SAI deployment, partially because of its cost effectiveness, stating that, \"Due to the high costs arising from the necessary transition to a carbon neutral economy, all options that could contribute to reducing the costs of this transition should be explored\". [28] (p. 6). In a similar vein, [PERSON] [29] has offered a calculation of a policy mix consisting of abatement and CE that proves to be less costly than rapid emission abatement exclusively: \"A combined mitigation/geoengineering approach to climate stabilization has a number of advantages over either alternative used separately. A relatively modest geoengineering investment (...) could reduce the economic and technological burden on mitigation substantially, by deferring the need for immediate or near-future cuts in CO2 emissions\" [29] (p. 454). As important as mitigation might be, an additional CE deployment could \"provide additional time to address the economic and technological challenges faced by a mitigation-only approach\" [29] (p. 452). Since some CE technologies could arguably be launched slowly and as easily be tapered off again, buying time could be a form of adjustment to correct and support the progress of abatement. \"Even absent any climate emergency, CE can be used as part of a low-cost inter-temporal climate response by deploying it incrementally to shave the near-term peak of global heating that would occur this century even with aggressive emission cuts. Such an incremental deployment, phased in then out over a century or so, could reduce near-term climate disruption and associated risks, thereby buying time and allowing emission cuts and adaptation measures to be made in an orderly program of technology deployment and capital turnover, at much lower cost and disruption than under more rapid deployment\" [30] (p. 318). Note, that [PERSON] and [PERSON] implicitly prolong the time scale of SAI deployment to \"a century or so\". Here, buying time refers to capital turnover and estimates of opportunity costs. We leave the point of capital turnover aside since this opens the door into the political economy of SAI [5]. We will not follow the line of reasoning that the real \"loss\" to be avoided by SAI is the loss in the relative value of capital stocks in fossil fuel intensive economic branches [5]. BTA supposes a management of an inevitable decarbonization of society while reducing its costs. Catastrophic climate change would likely unfold over a number of centuries, but avoiding it will require a technological revolution, and \"geoengineering might help to 'buy time' to develop and diffuse these new technologies\" [31] (p. 50). Here, BTA refers to diffusion of low-carbon technologies. CE technologies might render the transition easier, less costly or less abrupt, thereby taking some pressure off immediate choices of action. This is the climate economic dimension of BTA which deserves some additional reflection. There are two approaches in climate economics. The mainstream approach is oriented towards efficient (\"optimal\") solutions. Under this approach, SAI is an attractive tool. As has been argued elsewhere [32; 33], this approach is full of underlying moral assumptions, as rate of discount, value of a statistical life, monetization of ecosystem services, rate of substitution, aggregation of utility functions, etc. If so, the idea to calculate a global utility function for mankind over a century is illusionary at best, and ideological at worst. This is true a fortiori, if the calculation has to move within a complex dynamic portfolio being composed out of mitigation, adaptation, CDR, and SRM.