Future volcanic eruptions delay stratospheric ozone recovery

At present, volcanic sulfate aerosols can lead to stratospheric ozone loss under the presence of anthropogenic chlorofluorocarbons (CFCs). Recent satellite measurements showed that the 2015 Calbuco eruption, a small-magnitude eruption in Chile with 0.4 Tg of stratospheric sulfur injection, caused large-scale stratospheric ozone depletion during October 2015 in the Antarctic. According to the World Meteorological Organization, atmospheric CFC levels have declined since the 1980s, and the Antarctic ozone hole is expected to be healed by around mid-century. In the absence of CFCs, future volcanic eruptions producing stratospheric volcanic sulfate aerosol are expected to increase stratospheric ozone column concentrations. However, it remains uncertain whether future volcanic eruptions will lead to an earlier or a delayed recovery in stratospheric ozone back to 1980s levels.

To investigate how future volcanic eruptions affect stratospheric ozone recovery, we generated stochastic future eruption scenarios based on an array of bipolar ice cores, satellite measurements and geological records. We then selected the low-end, median and high-end future stochastic scenarios to perform simulations from 2015 to 2100 using a plume-aerosol-chemistry-climate modelling framework, UKESM-VPLUME with interactive volcanic aerosols. Our model results show that future volcanic eruptions can delay the recovery of the global stratospheric ozone column, as opposed to a previous modelling study that suggested future eruptions will lead to an earlier recovery of the global stratospheric ozone column. In addition, our stochastic scenarios show that future eruptions can potentially delay the recovery of Antarctic total ozone column by 2 to 3 years, depending on the timing, magnitude and latitude of the eruptions. Our results offer insights into the role of future volcanic eruptions in affecting global and polar stratospheric ozone recovery. We also highlight the importance of incorporating interactive volcanic sulfate aerosols in future modelling studies to assess the impact of volcanic eruptions on stratospheric ozone.