Abstract
We investigate the climatic effects of volcanic eruptions spanning from
Mt.\ Pinatubo-sized events to super-volcanoes. The study
is based on ensemble simulations in the Community Earth System Model
Version 2 (CESM2) climate model using the Whole Atmosphere Community
Climate Model Version 6 (WACCM6) atmosphere model. Our analysis focuses
on the impact of different \ce{SO2}-amount injections
on stratospheric aerosol optical depth (AOD), effective radiative
forcing (RF), and global temperature anomalies. Unlike the traditional
linear models used for smaller eruptions, our results reveal a
non-linear relationship between RF and AOD for larger eruptions. We also
uncover a notable time-dependent decrease in aerosol forcing efficiency
across all eruption magnitudes during the first post-eruption year. In
addition, the study reveals that larger as compared to medium-sized
eruption events produce a delayed and sharper peak in AOD, and a
longer-lasting temperature response while the time evolution of RF
remains similar between the two eruption types. When including the
results of previous studies, we find that relating
\ce{SO2} to any other parameter is inconsistent across
models compared to the relationships between AOD, RF, and temperature
anomaly. Thus, we expect the largest uncertainty in model codes to
relate to the chemistry and physics of \ce{SO2}
evolution. Finally, we find that the peak RF approaches a limiting
value, and that the peak temperature response follows linearly,
effectively bounding the temperature anomaly to at most
\(\sim\SI{-12}{\kelvin}\).