Volcanic Eruptions and their Impact on Future Climate (VEC)

Introduction

Understanding of the future change in climate is a problem of utmost importance for the scientific community, society and policymakers. The influence of powerful volcanic eruptions on climate was recognised long ago. Recently, it was suggested that small volcanic eruptions can also influence climate. However, projections of future climate change in the recent and upcoming Intergovernmental Panel for Climate Change activity do not take into account any effects from either infrequent, explosive or more-numerous small volcanic eruptions, rendering our knowledge of future climate far from complete. To address this missing component in future climate change projections, we will make use of our coupled atmosphere-ocean-aerosol-chemistry-climate model (AOACCM). This model provides a powerful tool to investigate interaction between sulphate aerosols, atmospheric chemistry, ocean dynamics and climate. Our project will lead to the first comprehensive assessment of the long-term natural influence of volcanic eruptions on future climate projections, their uncertainties and their impact on extreme weather events. The work will provide more complete information about future climate change for society and policymakers.

Results and Discussion

To achieve the project goals, we will make use of AOACCM, which will provide a powerful tool to investigate interaction between sulphate aerosols, atmospheric chemistry, ocean dynamics and climate. We aim to prepare such a model by coupling our current chemistry-climate model (SOCOLv3, Stenke et al., 2013), SOCOLv3 with the sulphate aerosol module (SOCOL-AER, Sheng et al., 2015), and the Max Planck Institute Earth System Model (MPI-ESM, Giorgetta et al., 2013).

Here we present the first steps of the project implementation, namely, the results of the installation and tests of MPI-ESM and the installation of emissions from smaller (non-major) volcanoes to SOCOL-AER.

The MPI-ESM model consists of: i) coupled general circulation models for the atmosphere, ECHAM6 (successor of ECHAM5 used in SOCOLv3), and ocean, MPIOM, and ii) the subsystem models for land and vegetation, JSBACH, and for marine biogeochemistry, HAMOCC5. The main benefit of the ECHAM6 dynamical core compared to ECHAM5 is the better scaleability, which will allow us to use the new model with a higher horizontal and vertical resolution. The fully coupled Earth system will also allow us to take many climate feedbacks into account. As an illustration of the new model advantages, Figure 1 shows an annual mean spatial distribution of dimethyl sulphide (DMS), an important source of sulphur in the atmosphere, which is now interactively calculated by the HAMOCC5 module of MPI-ESM and was previously prescribed in SOCOL-AER.

The sulphate aerosol part of the model, developed in our group, is capable of explicitly calculating the sulphate aerosol properties and therefore treating different types of volcanic eruptions as well as other sources of sulphur containing species. This module did not previously take the temporal evolution of emissions from smaller volcanic eruptions into account. We now address this issue by preparing and installing new emissions based on a NASA SO₂ volcanic database. This provides information about location, amount of SO₂ released, volcanic cloud column height, and volcano elevation for 1979 – 2010 eruptions of all intensity including de-gassing eruptions.

VEC Final Scientific Report 2018

Download

VEC Literature Publications

Download

References

Giorgetta M.A. et al., (2013), JAMES, doi: 10.1002/jame.20038
Sheng J.-X. et al., (2015), J. Geophys. Res., 120, 256–276, doi: 10.1002/2014JD021985
Stenke A. et al., (2013), Geosci. Model Dev., 6(5), 1407–1427, doi: 10.5194/gmd-6-1407-2013