Journal Article

Volcanic Eruptions: A Source of Irreducible Uncertainty for Future Climates

Zanchettin, D.

2023

Overview

Volcanic forcing, a major natural source of climate variability, represents a challenge for current climate modeling because of the unpredictability and specificity of individual eruptions, and because of the complexity of processes linking the eruption to the climate response. Volcanic forcing is largely underrepresented in available future climate projections, which is a critical problem. The study by Man Mei Chim and Colleagues (Chim et al., 2023, https://doi.org/10.1029/2023GL103743) tackles this known unknown and reveals how climatically relevant volcanic activity may be stronger than currently thought in a future warmer climate, enhancing uncertainty of climate projections. The study exemplifies the profound implications of inaccuracies within simplified climate scenarios and motivates new research on volcanically forced climate variability. It also arouses some thoughts on climate uncertainty communication. Plain Language Summary Volcanic eruptions are a critical part of the earth system, capable of causing large climatic fluctuations over periods from years to decades. Available scenario experiments typically neglect volcanic forcing, which may cause systematic errors in future climate projections. Man Mei Chim and Colleagues (Chim et al., 2023, https://doi.org/10.1029/2023GL103743) use a series of statistical and mathematical models to comprehensively simulate how volcanic eruptions may affect climate during the 21st century. The results indicate that a more realistic representation of volcanic eruptions yields slightly less future warming and larger uncertainty than standard projections. In other words, we are less confident of future climate changes once we account for the (unpredictable) volcanic forcing. By considering future volcano‐climate interactions in their whole complexity and revealing a substantial role for small‐to‐moderate eruptions, the study places a new important piece in the volcano‐climate puzzle. It will motivate new coordinated research to improve the simulated representation of volcano‐climate interactions not only in the ambit of future climate scenarios but in paleoclimatic investigations and idealized volcanic experiments well. The research also reminds us of limitations inherent in climate model experiments and should foster improved communication of natural climate variability and associated uncertainties. Key Points The study by Man Mei Chim and Colleagues shows that volcanic forcing can strongly affect future climate projections The study reaffirms the importance of natural variability for future climates, stimulating research on volcano‐climate interactions Volcanic forcing remains unpredictable, which rises the question of how to communicate irreducible climate projection uncertainties

• Publisher: John Wiley & Sons, Inc,Wiley
• Subject: Climate / Climate change / Climate models / climate projections / Climate variability / Communication / Complexity / Eruptions / Future climates / Mathematical models / Representations / Series (mathematics) / Specificity / Statistical analysis / Systematic errors / Uncertainty / Variability / Volcanic activity / Volcanic eruptions / volcanic forcing / Volcanoes