Flow tube experiment. (abstract) “We model ozone response incorporating the experimental uptake coefficients in the AER-2D model. With our new empirical reaction model, the global mean ozone column is reduced by up to 3%, whereas the previous work predicted up to 27% increase for the same SG scenario. This result is robust under our experimental uncertainty and many other assumptions. We outline systematic uncertainties that remain and provide three examples of experiments that might further reduce uncertainties of CaCO3 SG. Finally, we highlight the importance of the link between experiments and models in studies of SG. Dia et al acknowledge Cziczo polar stratospheric cloud nucleation.” Conclusions, “This study may have lessons for management of solar geoengineering research. Sound estimates of SG’s risks and efficacy will require experiments and models. Current estimates are almost entirely based on large-scale modeling. Models are crucial, but overreliance on models may encourage overconfidence when users ignore the simplifications hidden in their assumptions. Empirical methods are needed to help reduce uncertainty. Models can explore how results depend on uncertainty in parameters to motivate experimental research which, in turn, can provide better constraints on parameters used in models. The back-and-forth between the experimental and modeling communities is essential for environmental science. The complexity of experimental results like these may serve as a useful reminder of the deep uncertainties underlying predictions about the consequences of solar geoengineering.”
Dai, Keith, et al., Experimental reaction rates constrain estimates of ozone response to calcium carbonate geoengineering, Nature Communications, December 15, 2020.
https://www.nature.com/articles/s43247-020-00058-7
