SAI using sulfates would likely reduce the polar stratospheric ozone burden and delay the Antarctic ozone hole recovery. SAI impacts ozone both via heterogeneous chemistry occurring on the aerosols, and via induced changes on the large-scale stratospheric circulation.
Metric
SAI at 0.5°C cooling causes mid-latitude Northern or Southern Hemisphere ozone to drop below the 1990s minimum
Uncertainty
The processes which control the ozone response to SAI are fairly well understood. Our chosen metric is quite a high-bar for the uncertainty to meet, so even with significant inter-model disagreement at present, we still estimate under a 10% probability of this outcome.
Decision relevance
If ozone levels were to drop below the 1990s minimum, this would constitute a greater than 20% change in ozone levels. Stratospheric ozone has large human health impacts as it blocks some harmful UV-B and UV-C radiation; the Montreal Protocol's success in limiting its loss has greatly reduced skin cancer and cataract cases around the world (e.g. EPA, 2020).