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

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 such a deployment would require aircraft and other infrastructure that does not currently exist. Given the span required to develop and certify a novel aircraft program and thereafter 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.