An assessment of the infrastructural and temporal barriers constraining a near-term implementation of a global stratospheric aerosol injection program

Abstract

Abstract Models of stratospheric aerosol injection deployment scenarios have often assumed that a global sunscreen could be applied to the Earth on relatively short notice, perhaps in response to a climate emergency. This emergency response framing confuses the timescales associated with the commencement of such a program. Once deployed, stratospheric aerosols could cool the Earth quite quickly, but the most commonly assumed deployment scenarios would require aircraft and other infrastructure that does not currently exist. Given the span required to develop and certify a novel aircraft program and to subsequently build a fleet numbering in the hundreds, scenario builders should assume a roughly two-decade interval between a funded launch decision and the attainment of a target level of cooling.