• An Erratum to this article was published on 04 October 2017


Aerosols have a potentially large effect on climate, particularly through their interactions with clouds, but the magnitude of this effect is highly uncertain. Large volcanic eruptions produce sulfur dioxide, which in turn produces aerosols; these eruptions thus represent a natural experiment through which to quantify aerosol–cloud interactions. Here we show that the massive 2014–2015 fissure eruption in Holuhraun, Iceland, reduced the size of liquid cloud droplets—consistent with expectations—but had no discernible effect on other cloud properties. The reduction in droplet size led to cloud brightening and global-mean radiative forcing of around −0.2 watts per square metre for September to October 2014. Changes in cloud amount or cloud liquid water path, however, were undetectable, indicating that these indirect effects, and cloud systems in general, are well buffered against aerosol changes. This result will reduce uncertainties in future climate projections, because we are now able to reject results from climate models with an excessive liquid-water-path response.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.


  1. 1.

    The influence of pollution on the shortwave albedo of clouds. J. Atmos. Sci. 34, 1149–1152 (1977)

  2. 2.

    Aerosols, cloud microphysics, and fractional cloudiness. Science 245, 1227–1230 (1989)

  3. 3.

    & Estimates of the direct and indirect radiative forcing due to tropospheric aerosols: a review. Rev. Geophys. 38, 513–543 (2000)

  4. 4.

    , & Disentangling the role of microphysical and dynamical effects in determining cloud properties over the Atlantic. Geophys. Res. Lett. 33, L09802 (2006)

  5. 5.

    & Meteorological bias in satellite estimates of aerosol-cloud relationships. Geophys. Res. Lett. 34, L16824 (2007)

  6. 6.

    , & Constraining the aerosol influence on cloud fraction. J. Geophys. Res. Atmos. 121, 3566–3583 (2016)

  7. 7.

    et al. The impact of humidity above stratiform clouds on indirect climate forcing. Nature 432, 1014–1017 (2004)

  8. 8.

    , , , & Aerosol impacts on the diurnal cycle of marine stratocumulus. J. Atmos. Sci. 65, 2705–2718 (2008)

  9. 9.

    & Untangling aerosol effects on clouds and precipitation in a buffered system. Nature 461, 607–613 (2009)

  10. 10.

    , & Aerosol-cloud-precipitation effects over Germany as simulated by a convective-scale numerical weather prediction model. Atmos. Chem. Phys. 12, 709–725 (2012)

  11. 11.

    & On the relationship between responses in cloud water and precipitation to changes in aerosol. Atmos. Chem. Phys. 14, 11817–11831 (2014)

  12. 12.

    , , & Large-eddy simulation of the transient and near-equilibrium behaviour of precipitating shallow convection. J. Adv. Model. Earth Syst. 7, 1918–1937 (2015)

  13. 13.

    et al. Aerosol indirect effects — general circulation model intercomparison and evaluation with satellite data. Atmos. Chem. Phys. 9, 8697–8717 (2009)

  14. 14.

    , & Satellite methods underestimate indirect climate forcing by aerosols. Proc. Natl Acad. Sci. USA 108, 13404–13408 (2011)

  15. 15.

    Rethinking the lower bound on aerosol radiative forcing. J. Clim. 28, 4794–4819 (2015)

  16. 16.

    et al. Challenges in constraining anthropogenic aerosol effects on cloud radiative forcing using present-day spatiotemporal variability. Proc. Natl Acad. Sci. USA 113, 5804–5811 (2016)

  17. 17.

    . et al. in Climate Change 2013: The Physical Science Basis (eds et al.) Ch. 7 (Cambridge Univ. Press, 2013)

  18. 18.

    et al. Large contribution of natural aerosols to uncertainty in indirect forcing. Nature 503, 67–71 (2013)

  19. 19.

    et al. Occurrence of pristine aerosol environments on a polluted planet. Proc. Natl Acad. Sci. USA 111, 18466–18471 (2014)

  20. 20.

    et al. Total aerosol effect: radiative forcing or radiative flux perturbation? Atmos. Chem. Phys. 10, 3235–3246 (2010)

  21. 21.

    Putting the clouds back in aerosol-cloud interactions. Atmos. Chem. Phys. 15, 12397–12411 (2015)

  22. 22.

    , & Atmospheric effects of the Mt Pinatubo eruption. Nature 373, 399–404 (1995)

  23. 23.

    Satellite observations of the impact of weak volcanic activity on marine clouds. J. Geophys. Res. Atmos. 113, D14S19 (2008)

  24. 24.

    , & Microphysical, macrophysical and radiative signatures of volcanic aerosols in trade wind cumulus observed by the A-Train. Atmos. Chem. Phys. 11, 7119–7132 (2011)

  25. 25.

    et al. Importance of tropospheric volcanic aerosol for indirect radiative forcing of climate. Atmos. Chem. Phys. 12, 7321–7339 (2012)

  26. 26.

    , & The impact of volcanic eruptions in the period 2000–2013 on global mean temperature trends evaluated in the HadGEM2-ES climate model. Atmos. Sci. Lett. 15, 92–96 (2014)

  27. 27.

    , & Consistent estimates from satellites and models for the first aerosol indirect forcing. Geophys. Res. Lett. 39, L13810 (2012)

  28. 28.

    , & Icelandic volcanic emissions and climate. Nat. Geosci. 8, 243 (2015)

  29. 29.

    & Observations of a substantial cloud-aerosol indirect effect during the 2014–2015 Bárðarbunga-Veiðivötn fissure eruption in Iceland. Geophys. Res. Lett. 42, 10409–10414 (2015)

  30. 30.

    et al. Tracking and quantifying volcanic SO2 with IASI, the September 2007 eruption at Jebel at Tair. Atmos. Chem. Phys. 8, 7723–7734 (2008)

  31. 31.

    et al. Observations of the eruption of the Sarychev volcano and simulations using the HadGEM2 climate model. J. Geophys. Res. Atmos. 115, D21212 (2010)

  32. 32.

    et al. Satellite detection, long-range transport, and air quality impacts of volcanic sulfur dioxide from the 2014–2015 flood lava eruption at Bárðarbunga (Iceland). J. Geophys. Res. Atmos. 120, 9739–9757 (2015)

  33. 33.

    , , , & Sulphur release from flood lava eruptions in the Veidivötn, Grímsvötn and Katla volcanic systems, Iceland. Geol. Soc. Lond. Spec. Publ. 213, 103–121 (2003)

  34. 34.

    et al. Neither dust nor black carbon causing apparent albedo decline in Greenland’s dry snow zone: implications for MODIS C5 surface reflectance. Geophys. Res. Lett. 42, 9319–9327 (2015)

  35. 35.

    et al. MODIS Atmosphere L2 Cloud Product (06_L2) (NASA MODIS Adaptive Processing System, Goddard Space Flight Center, 2015); available at

  36. 36.

    & An assessment of differences between cloud effective particle radius retrievals for marine water clouds from three MODIS spectral bands. J. Geophys. Res. Atmos. 116, D20215 (2011)

  37. 37.

    & in Clouds in the Perturbed Climate System: Their Relationship to Energy Balance, Atmospheric Dynamics, and Precipitation (eds . & ) Ch. 8 (Strüngmann Forum Report, Vol. 2, MIT Press, 2009).

  38. 38.

    et al. Aerosol forcing in the Climate Model Intercomparison Project (CMIP5) simulations by HadGEM2-ES and the role of ammonium nitrate. J. Geophys. Res. Atmos. 116, D20206 (2011)

  39. 39.

    et al. Aerosol microphysics simulations of the Mt. Pinatubo eruption with the UM-UKCA composition-climate model. Atmos. Chem. Phys. 14, 11221–11246 (2014)

  40. 40.

    et al. Aerosol-climate interactions in the Norwegian Earth System Model — NorESM1-M. Geosci. Model Dev. 6, 207–244 (2013)

  41. 41.

    et al. The impact of the 1783–1784 AD Laki eruption on global aerosol formation processes and cloud condensation nuclei. Atmos. Chem. Phys. 10, 6025–6041 (2010)

  42. 42.

    et al. On the characteristics of aerosol indirect effect based on dynamic regimes in global climate models. Atmos. Chem. Phys. 16, 2765–2783 (2016)

  43. 43.

    , , & The source of discrepancies in aerosol–cloud–precipitation interactions between GCM and A-Train retrievals. Atmos. Chem. Phys. 16, 15413–15424 (2016)

  44. 44.

    , , & Radiative effects of global MODIS cloud regimes. J. Geophys. Res. Atmos. 121, 2299–2317 (2016)

  45. 45.

    et al. Modulation of cloud droplets and radiation over the North Pacific by sulfate aerosol erupted from Mount Kilauea. Sci. Online Lett. Atmos. 7, 77–80 (2011)

  46. 46.

    & Observational evidence for aerosol invigoration in shallow cumulus downstream of Mount Kilauea. Geophys. Res. Lett. 43, 2981–2988 (2016)

  47. 47.

    . et al. in Climate Change 2013: The Physical Science Basis (eds et al.) Ch. 8 (Cambridge Univ. Press, 2013)

  48. 48.

    , & Cloud tuning in a coupled climate model: impact on 20th century warming. Geophys. Res. Lett. 40, 2246–2251 (2013)

  49. 49.

    & Why do general circulation models overestimate the aerosol cloud lifetime effect? A case study comparing CAM5 and a CRM. Atmos. Chem. Phys. 17, 21–29 (2017)

Download references


J.M.H., A.J., M.D., B.T.J., C.E.J., J.R.K. and F.M.O.C. were supported by the Joint UK BEIS/Defra Met Office Hadley Centre Climate Programme (GA01101). The National Center for Atmospheric Research is sponsored by the US National Science Foundation. S.B. and L.C. are respectively Research Fellow and Research Associate funded by FRS-FNRS. P.S. acknowledges support from the European Research Council (ERC) project ACCLAIM (grant agreement FP7-280025). J.M.H., F.F.M., D.G.P. and P.S. were part-funded by the UK Natural Environment Research Council project ACID-PRUF (NE/I020148/1). A.S. was funded by an Academic Research Fellowship from the University of Leeds and NERC urgency grant NE/M021130/1 (‘The source and longevity of sulphur in an Icelandic flood basalt eruption plume’). R.A. was supported by the NERC SMURPHS project NE/N006054/1. G.W.M. was funded by the National Centre for Atmospheric Science, one of the UK Natural Environment Research Council’s research centres. D.P.G. is funded by the School of Earth and Environment at the University of Leeds. G.W.M. and S.D. acknowledge additional EU funding from the ERC under the FP7 consortium project MACC-II (grant agreement 283576) and Horizon 2020 project MACC-III (grant agreement 633080). G.W.M., K.S.C. and D.G. were also supported via the Leeds-Met Office Academic Partnership (ASCI project). The work done with CAM5-Oslo is supported by the Research Council of Norway through the EVA project (grant 229771), NOTUR project nn2345k and NorStore project ns2345k. We thank the following researchers who have contributed to the development version of CAM5-Oslo used in this study: K. Alterskjær, A. Grini, M. Hummel, T. Iversen, A. Kirkevåg, D. Olivié, M. Schulz and Ø. Seland. The AQUA/MODIS MYD08 L3 Global 1 Deg. data set was acquired from the Level-1 and Atmosphere Archive and Distribution System (LAADS) Distributed Active Archive Center (DAAC), located in the Goddard Space Flight Center in Greenbelt, Maryland (https://ladsweb.nascom.nasa.gov/). This work is dedicated to the memory of co-author Jón Egill Kristjánsson who died in a climbing accident in Norway.

Author information

Author notes

    • Daniel G. Partridge

    Present address: College of Engineering, Mathematics, and Physical Sciences, University of Exeter, Exeter, UK.

    • Jón Egill Kristjánsson



  1. College of Engineering, Mathematics, and Physical Sciences, University of Exeter, Exeter, UK

    • Florent F. Malavelle
    •  & Jim M. Haywood
  2. Met Office Hadley Centre, Exeter, UK

    • Jim M. Haywood
    • , Andy Jones
    • , Mohit Dalvi
    • , Adrian A. Hill
    • , Ben T. Johnson
    • , Colin E. Johnson
    • , Jeff R. Knight
    •  & Fiona M. O’Connor
  3. National Center for Atmospheric Research, Boulder, Colorado, USA

    • Andrew Gettelman
  4. Chimie Quantique et Photophysique CP160/09, Université Libre de Bruxelles (ULB), Bruxelles, Belgium

    • Lieven Clarisse
    •  & Sophie Bauduin
  5. Department of Meteorology, University of Reading, Reading, UK

    • Richard P. Allan
    •  & Nicolas Bellouin
  6. National Centre for Earth Observation, University of Reading, Reading, UK

    • Richard P. Allan
  7. Department of Geosciences, University of Oslo, Oslo, Norway

    • Inger Helene H. Karset
    •  & Jón Egill Kristjánsson
  8. Earth Sciences Division, NASA GSFC, Greenbelt, Maryland, USA

    • Lazaros Oreopoulos
    • , Nayeong Cho
    • , Dongmin Lee
    •  & Steven Platnick
  9. USRA, Columbia, Maryland, USA

    • Nayeong Cho
  10. Morgan State University, Baltimore, Maryland, USA

    • Dongmin Lee
  11. Laboratoire de Météorologie Dynamique, IPSL, UPMC/CNRS, Jussieu, France

    • Olivier Boucher
  12. School of Earth and Environment, University of Leeds, Leeds, UK

    • Daniel P. Grosvenor
    • , Ken S. Carslaw
    • , Sandip Dhomse
    • , Graham W. Mann
    •  & Anja Schmidt
  13. National Centre for Atmospheric Science, University of Leeds, Leeds, UK

    • Graham W. Mann
  14. School of Earth and Environmental Sciences, University of Manchester, Manchester, UK

    • Hugh Coe
    •  & Margaret E. Hartley
  15. Department of Environmental Science and Analytical Chemistry, University of Stockholm, Stockholm, Sweden

    • Daniel G. Partridge
  16. Bert Bolin Centre for Climate Research, University of Stockholm, Stockholm, Sweden

    • Daniel G. Partridge
  17. Atmospheric, Oceanic and Planetary Physics, Department of Physics, University of Oxford, Oxford, UK

    • Daniel G. Partridge
    •  & Philip Stier
  18. Center for International Climate and Environmental Research, Oslo, Norway

    • Gunnar Myhre
  19. Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA

    • Graeme L. Stephens
    •  & Hanii Takahashi
  20. Joint Institute for Regional Earth System Science and Engineering, University of California, Los Angeles, California, USA

    • Hanii Takahashi
  21. Faculty of Earth Sciences, University of Iceland, Reykjavik, Iceland

    • Thorvaldur Thordarson


  1. Search for Florent F. Malavelle in:

  2. Search for Jim M. Haywood in:

  3. Search for Andy Jones in:

  4. Search for Andrew Gettelman in:

  5. Search for Lieven Clarisse in:

  6. Search for Sophie Bauduin in:

  7. Search for Richard P. Allan in:

  8. Search for Inger Helene H. Karset in:

  9. Search for Jón Egill Kristjánsson in:

  10. Search for Lazaros Oreopoulos in:

  11. Search for Nayeong Cho in:

  12. Search for Dongmin Lee in:

  13. Search for Nicolas Bellouin in:

  14. Search for Olivier Boucher in:

  15. Search for Daniel P. Grosvenor in:

  16. Search for Ken S. Carslaw in:

  17. Search for Sandip Dhomse in:

  18. Search for Graham W. Mann in:

  19. Search for Anja Schmidt in:

  20. Search for Hugh Coe in:

  21. Search for Margaret E. Hartley in:

  22. Search for Mohit Dalvi in:

  23. Search for Adrian A. Hill in:

  24. Search for Ben T. Johnson in:

  25. Search for Colin E. Johnson in:

  26. Search for Jeff R. Knight in:

  27. Search for Fiona M. O’Connor in:

  28. Search for Daniel G. Partridge in:

  29. Search for Philip Stier in:

  30. Search for Gunnar Myhre in:

  31. Search for Steven Platnick in:

  32. Search for Graeme L. Stephens in:

  33. Search for Hanii Takahashi in:

  34. Search for Thorvaldur Thordarson in:


F.F.M. (text, processing and analysis of the satellite data and the model results), J.M.H. (text, analysis of the satellite data and the model results, radiative transfer calculations), A.J., A.G., I.H.H.K. and J.E.K. (model runs), R.A. (processing of the CERES data and contribution to the text), L.C. and S.B. (processing of the IASI data and contribution to the text), L.O., N.C. and D.L. (MODIS cloud regimes), D.P.G. (estimate of CDNC from MODIS data), T.T. and M.E.H. (provided emission estimates for the 2014–2015 eruption at Holuhraun), A.J., N.B., O.B., K.S.C., S.D., G.W.M., A.S., H.C., M.D., A.A.H., B.T.J., C.E.J., F.M.O.C., D.G.P. and P.S. (contribution to the development of UKCA), and G.M., S.P., G.L.S., H.T. and J.R.K. (discussion contributing to text and/or help with the MODIS data).

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Florent F. Malavelle.

Reviewer Information Nature thanks R. Allen, M. Schulz, B. Toon and the other anonymous reviewer(s) for their contribution to the peer review of this work.

Publisher's note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

PDF files

  1. 1.

    Supplementary Information

    This file contains Supplementary Methods, a Supplementary Discussion, Supplementary Tables, Supplementary Figures, Code Availability, Data availability and Supplementary References.


  1. 1.

    Evolution of the S02 plume

    This animation shows 60 days (from the 1st of September 2014) of IASI data (top) and HadGEM3 simulation results (Bottom) of the SO2 atmospheric column content expressed in Dobson units (DU).

  2. 2.

    Cloud coverage over Iceland

    This animation shows 30 days (from the 1st of September 2014) of MODIS data from daily Aqua orbits above Iceland processed to look like true-color photographs of the planet's surface.

About this article

Publication history






Further reading


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.