PNNL

Abstract

Solar geoengineering has been proposed as a method of meeting 2 climate objectives, such as reduced globally averaged surface temperatures. However, because of incomplete under-standing of the effects of geoengineering on the climate system, its implementation would be in the presence of substantial uncertainties. In our study, we use two fully coupled atmosphere-ocean general circulation models: one in which the geoengineering strategy is designed, and one in which geoengineering is implemented (a real-world proxy). We show 8 that regularly adjusting the amount of solar geoengineering in response to departures of the observed global mean climate state from the predetermined objective (sequential decision making; an explicit feedback approach) can manage uncertainties and result in achievement of the climate objective in both the design model and the real-world proxy. This approach results in substantially less error in meeting global climate objectives than using a predeter-mined time series of how much geoengineering to use, especially if the estimated sensitivity to geoengineering is inaccurate.