Large uncertainty in volcanic aerosol radiative forcing derived from ice cores

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Authors

Lauren Marshall , Anja Schmidt, Jill Johnson, Graham Mann, Lindsay Lee, Ken Carslaw

Abstract

Reconstructions of volcanic aerosol radiative forcing are required to understand past climate variability. Currently, reconstructions of pre-20th century volcanic forcing are derived from sulfate concentrations measured in polar ice cores, predominantly using a relationship between average ice sheet sulfate deposition and stratospheric sulfate aerosol based on a single explosive eruption - the 1991 eruption of Mt. Pinatubo. Here we derive volcanic radiative forcing from ice-core-records using a perturbed parameter ensemble of aerosol-climate model simulations of explosive eruptions, which enables the uncertainty to be estimated. We find that a very wide range of eruptions with different sulfur dioxide emissions, eruption latitudes, emission altitudes and in different seasons produce ice-sheet sulfate deposition consistent with ice-core-derived values for eruptions during the last 2500 years. Consequently, we find a large uncertainty in the volcanic forcing, suggesting uncertainties on the global mean temperature response of more than 1C for several past explosive eruptions, which has not been previously accounted for.

DOI

https://doi.org/10.31223/osf.io/mbtg8

Subjects

Atmospheric Sciences, Climate, Earth Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Volcanology

Keywords

aerosol, radiative forcing, statistical emulation, volcanic eruptions

Dates

Published: 2019-06-20 21:24

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License

CC BY Attribution 4.0 International

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