Examining the climate impacts of future volcanic eruptions

Large explosive volcanic eruptions can induce global climate impacts on decadal to multi-decadal timescales. In current climate models, future volcanic eruptions are represented in terms of a time-averaged volcanic forcing that ignores the sporadic nature of volcanic eruptions. This conventional representation does not account for how climate change might affect the dynamics of volcanic plumes and the stratospheric sulfate aerosol lifecycle and, ultimately, volcanic radiative forcing. To account for these climate-volcano feedbacks in climate projections, we perform model simulations from 2015 to 2100 with two key innovations: (1) a stochastic resampling approach to generate realistic future eruption scenarios based on historical volcanic eruptions recorded by ice cores and satellites in the past 11,500 years; and (2) a new modelling framework, UKESM-VPLUME, which couples a 1-D eruptive plume model (Plumeria) with an Earth System Model (UKESM) to consider the impacts of changing atmospheric conditions on eruptive plume heights. Our results show that considering sporadic small-magnitude volcanic eruptions in a future warming scenario can lead to a noticeable difference in global surface temperatures as well as on the time at which temperatures exceed 1.5°C above pre-industrial levels. Our study highlights the importance of considering sporadic eruptions and the changes in eruptive plume heights in a future warmer climate.  The UKESM-VPLUME model framework enables us to quantify the impacts of climate change on volcanic radiative forcing in an Earth System model, which in future research allows us to better evaluate the climate impacts of volcanic eruptions under global warming.