Stratospheric Ozone Response to Future Volcanic Eruptions

Explosive volcanic eruptions have considerable potential to disrupt atmospheric chemical inventories and climates on regional and global scales. The 1991 eruption of Mt. Pinatubo demonstrated the important role of heterogeneous reactions on volcanic aerosols as they relate to catalytic ozone depletion; importantly, significant column ozone losses were observed at mid-latitudes during the following two years. In contrast, scientific consensus holds that volcanic activity in future atmospheres will exert a positive effect on the ozone budget. The different ozone responses are due to the dependence of the aerosol-mediated perturbation of the ozone-sink chemical feedbacks to the trace gas composition of the stratosphere. In situ measurements represent an ideal means of studying these regional-to-global scale phenomena at high resolution. Here, we employ a 2D chemical transport model to examine the sensitivity of contemporary and future atmospheres to volcanic perturbation, finding that the ozone layer remains sensitive to stratospheric aerosol enhancement longer than previously believed. In particular, we examine the sensitivity of column ozone to volcanic aerosol in the four representative concentration pathway (RCP) storylines and also evaluate the column ozone response to volcanic aerosol as a function of bromine from biogenic, very short-lived (VSL) bromocarbons. Finally, we explore the implications of the stratospheric co-injection of hydrogen halides with sulfur dioxide on column ozone.