Potential volcanic impacts on future climate variability

Abstract

Projections of future climate do not typically include the effects of volcanic activity. By incorporating a range of volcanic futures into a coupled model, it is shown that volcanic forcing has quantifiable impacts on the time at which anthropogenic signatures emerge across various climate metrics. Volcanic activity plays a strong role in modulating climate variability1. Most model projections of the twenty-first century, however, under-sample future volcanic effects by not representing the range of plausible eruption scenarios2,3,4. Here, we explore how sixty possible volcanic futures, consistent with ice-core records5, impact climate variability projections of the Norwegian Earth System Model (NorESM)6 under RCP4.5 (ref. 7). The inclusion of volcanic forcing enhances climate variability on annual-to-decadal timescales. Although decades with negative global temperature trends become ∼50% more commonplace with volcanic activity, these are unlikely to be able to mitigate long-term anthropogenic warming. Volcanic activity also impacts probabilistic projections of global radiation, sea level, ocean circulation, and sea-ice variability, the local-scale effects of which are detectable when quantifying the time of emergence8. These results highlight the importance and feasibility of representing volcanic uncertainty in future climate assessments.