Abstract

Explosive volcanic eruptions are a major driver of climate variability, but whether climate change in turn affects volcanic sulfate aerosols and their radiative forcing remains unexplored. Here I combine an eruptive column model with an aerosol-climate model to show that the aerosol optical depth perturbation from frequent moderate-magnitude tropical eruptions (e.g. Nabro 2011) will be reduced by 75% in a high-end warming scenario compared to today, a consequence of the tropopause height rise. In contrast, the radiative forcing from infrequent large-magnitude tropical eruptions (e.g. Mt. Pinatubo 1991) will be exacerbated by 30% primarily because of a decrease by 10% of the aerosol size driven by the acceleration of the Brewer-Dobson circulation and an increase in eruptive column height. This increased forcing amplifies stratospheric warming, tropospheric cooling and surface cooling by 52%, 55% and 15%. Changes in eruptive column dynamics and the injection height of sulfur gases prove key to accurately predict the climate response to future eruptions. In a second part, I will discuss the extent to which eruptive column models can capture the impact of atmospheric conditions on volcanic plume rise, and in particular constraints from both laboratory experiments and natural eruptions. I will briefly introduce the upcoming Independent Volcanic Eruption Source Parameter Archive (IVESPA, https://thm.iavceivolcano.org/example-2/esp-working-group.html), which is a new community database primarly motivated by the evaluation of eruptive column models.