Volc2Clim is a webtool to calculate aerosol optical properties, global-mean radiative forcing and changes in global-mean surface temperature in response to volcanic sulfur emitted by explosive volcanic eruptions. It combines three simple and peer-reviewed models:

  1. EVA_H, which predicts perturbations in aerosol optical properties, such as the stratospheric aerosol optical depth (SAOD) for a given mass of sulfur dioxide (SO₂), injection altitude and injection latitude (Aubry et al., 2020; https://github.com/thomasaubry/EVA_H)
  2. A scaling factor that reflects the relationship between the global-mean SAOD perturbation (at 550 nm) and the global-mean effective volcanic radiative forcing at the top of the atmosphere (Schmidt et al., 2018; Marshall et al., 2020)
  3. FaIR, a simple climate response model that calculates the global-mean surface temperature response based on the global-mean effective volcanic radiative forcing calculated in 2. (Smith et al., 2018; https://github.com/OMS-NetZero/FAIR)

All these models heavily simplify processes involved in the volcanic sulfate aerosol lifecycle and in the climate system, and they are empirical in nature. The results obtained with Vol2Clim should thus be interpreted with caution, especially for eruptions whose characteristic differ from any historical eruption during the period 1979 to 2021, based on which EVA-H is calibrated. The predictions also solely account for the climate effects of volcanic sulfur dioxide emissions and not, for example, for the impact of volcanic ash, halogens or water vapor that might be co-injected with sulfur.

The user can provide eruption source parameters characterizing the volcanic SO₂ injection and set some of the parameters used by the underlying models. Volc2Clim will output: i) a set of downloadable figures showing key outputs from the models; ii) a csv file containing the output data from the models; and iii) a netcdf file containing 4-dimensional aerosol optical properties predicted by EVA_H that can be used as boundary conditions in global climate models that do not have interactive stratospheric aerosol capabilities.

Values from key parameters (e.g., peak global monthly mean SAOD at 550nm) are also printed to the screen, including the Volcano Climate Index (VCI, Schmidt and Black 2022, https://volcano-climate.github.io/vci/). The VCI is a scale that measures the magnitude of the volcanic climate response and takes values from 0 to 6+. It is similar to the Richter scale for the magnitude of earthquakes or the Volcanic Explosivity Index (VEI) for the explosivity of volcanic eruptions.

Please refer to the papers below for details of each specific model used in Volc2Clim, and feel free to contact Anja Schmidt (anja.schmidt@dlr.de) and Thomas Aubry (t.aubry@exeter.ac.uk) if you have any question or feedback. We hope that you enjoy Volc2Clim for your teaching, research and operational needs, or if you are just a curious person learning about volcanoes and climate!

Volc2Clim is an open source project released under the MIT licence. You can see the source code on GitHub at https://github.com/cemac/volc2clim/.


If you use Volc2Clim in any scientific output, we ask that you acknowledge it by citing:

Anja Schmidt, Thomas J. Aubry, Richard Rigby, John Stevenson and Susan C. Loughlin, Volc2Clim online tool, https://doi.org/10.5281/zenodo.7602062, https://volc2clim.bgs.ac.uk/.

Please also kindly cite the publications referred below describing key components of Volc2Clim.


Aubry, T. J., Toohey, M., Marshall, L., Schmidt, A., Jellinek, A. M. (2019). A new volcanic stratospheric sulfate aerosol forcing emulator (EVA_ H): Comparison with interactive stratospheric aerosol models, Journal of Geophysical Research: Atmospheres, 125, doi: 10.1029/2019JD031303, https://github.com/thomasaubry/EVA_H..

Marshall, L.R., Smith, C. J., Forster,P. M., Aubry, T. J., Andrews, T., Schmidt, A. (2020). Large variations in volcanic aerosol forcing efficiency due to eruption source parameters and rapid adjustments. Geophysical Research Letters, 47, doi: 10.1029/2020GL090241.

Smith, C. J., Forster, P. M., Allen, M., Leach, N., Millar, R. J., Passerello, G. A., Regayre, L. A. (2018). FAIR v1.3: A simple emissions-based impulse response and carbon cycle model, Geosci. Model Dev. 11, 2273–2297, doi: 10.5194/gmd-11-2273-2018, https://github.com/OMS-NetZero/FAIR.

Schmidt, A., Black, B.A. (2022), Reckoning with the Rocky Relationship Between Eruption Size and Climate Response: Toward a Volcano-Climate Index. Annual Review of Earth and Planetary Sciences, 50, pp.627-661. doi: 10.1146/annurev-earth-080921-052816, https://volcano-climate.github.io/vci/.

Schmidt, A., Mills, M. J., Ghan, S., Gregory, J. M., Allan, R. P., Andrews, T., et al. (2018). Volcanic radiative forcing from 1979 to 2015. Journal of Geophysical Research: Atmospheres, 123, 12,491-12,508. 10.1029/2018JD028776.


We acknowledge funding from UKESM: The UK Earth System Modelling project was funded by the UKRI – Natural Environment Research Council (NERC) national capability grant number NE/N017951/1 and the Met Office. We also acknowledge funding from UK Natural Environment Research Council grants NE/S000887/1 (VOL-CLIM) and NE/S00436X/1 (V-PLUS).