Small volcanic eruptions and the global warming ‘pause’

Wellcome Library, London  Mount Vesuvius emitting a column of smoke after its eruption on 8 August 1779. Coloured etching by Pietro Fabris, 1779.

Wellcome Library, London
A small eruption of Mount Vesuvius on 8 August 1779, part of a sequence that culminated in a moderate eruption. Coloured etching by Pietro Fabris, 1779. Copyrighted work available under Creative Commons Attribution only licence CC BY 2.0

A new paper in Nature Geoscience by Santer and colleagues revisits the volcanic scenarios used in modern climate model simulations. The authors consider the effects of including a ‘more realistic’ model for the influence of small volcanic eruptions on the climate system over the past two decades. Of course, more realistic means more difficult.. and one of the long-standing and unresolved problems with small volcanic eruptions is that not only are they small, but their consequences are unpredictable. These complications arise, in part, from the fact that the part of the volcanic system that is responsible for the climate impact are the emitted gases (notably, sulphur dioxide or SO2), and not the volcanic ash. In real volcanoes, these two parameters don’t seem to be very well correlated – and it has been well known for some time that small but explosive eruptions of sulphur-rich magmas might well have a disproportionate effect on the climate system (see, for example, Rampino and Self, 1984; Miles et al., 2004). For this reason, models of volcano-climate impact that only use information on eruption size (as measured by the Volcanic Explosivity Index) will usually only be a poor approximation to reality. A better representation might instead be a volcanic sulphur dioxide climatology, building on the extensive work of the volcanic emissions satellite-remote sensing community since the first volcanic plume satellite measurements in 1979. The currently most up to date compilations of volcanic SO2 emissions since 1996 can be found in Carn et al., (2003) and McCormick et al., (2013).

Reading between the lines, it looks as though Santer and colleagues have come to a similar conclusion – finding that their model simulations get a little closer to observations of tropospheric temperature trends when they introduce a ‘realistic’ volcanic scenario to simulate the past 25 years of eruptions. What a pity that the volcanic dataset they relied on to line up particular eruptions with aerosol optical depth perturbations was patched together from secondary sources.  Clearly, as they suggest, more work is needed – but why not start by bringing the  climate modeling community and volcanologists together to find out what we each think that we know ?

Further reading.

Carn SA et al. 2003 Volcanic eruption detection by the Total Ozone Mapping Spectrometer (TOMS) instruments: a 22-year record of sulphur dioxide and ash emissions, In: Oppenheimer et al. (eds), Volcanic Degassing, Geological Society, London, Special Publications 213, 177-202.

McCormick BT et al. 2013 Volcano monitoring applications of the Ozone Monitoring Instrument, In: Pyle DM et al. (eds), Remote Sensing of Volcanoes and Volcanic ProcessesGeological Society, London, Special Publications 280, 1259-291.

Miles GM, Grainger RG and Highwood EJ 2004 The significance of volcanic eruption strength and frequency for climate Q. J. R. Met. Soc. 130 2361–76

Rampino MR and Self S 1984 Sulphur-rich volcanic eruptions and stratospheric aerosols, Nature 310, 677 – 679

Santer B et al, 2014, Volcanic contribution to decadal changes in tropospheric temperature Nature Geoscience (2014) doi:10.1038/ngeo2098

Related posts.

For more information on William Hamilton and Vesuvius, try this delightful blog post by Karen Meyer-Roux.

Remote sensing of volcanoes and volcanic processes


The spectacular front cover of the Geological Society of London Special Publication 380 – with many thanks to Elspeth Robertson and ESA for this SPOT5 image of Longonot volcano, Kenya.

A major goal of volcanological science is understand the processes that underlie volcanic activity, and to use this understanding to help to reduce volcanic risk. Advances in instruments and techniques mean that scientists can now measure many different aspects of the behaviour of  restless or active volcanoes, including seismicity (to detect magma movement at depth, for example); deformation (often reflecting pressure changes at depth); and emissions of heat and gas.  With the exception of seismicity, which requires sensitive instruments placed close to the volcano, many of these measurements can now be made remotely using instruments on board satellites or aircraft.

Remote-sensing techniques have transformed our capacity to detect, monitor and measure volcanic activity worldwide. In the past 35 years, applications have moved from the first satellite remote-sensing observations of the rise and spread of a volcanic plume and volcanic gases from an explosive volcanic eruption (the April 1979 eruption of the Soufriere of St Vincent in the Caribbean); to the current situation where constellations of satellites are used to provide routine monitoring of volcanic gas emissions, volcanic hotspots and volcano deformation. As well as dramatically improving our ability to monitor the progress of volcanic eruptions, these techniques also help us to understand better how volcanoes work by providing long-term data on what happens at volcanoes when they are not erupting; and by making it possible to compare the behaviour of different volcanoes in ways that are simply not possible from the ground, or with ground-based observations.

In a new Geological Society of London Special Publication, we have brought together a selection of papers that give a broad perspective of the current state of the art in the remote sensing of volcanoes and volcanic processes. The 14 papers in the volume focus on the observation, modelling and interpretation of satellite-remote sensing of volcanoes: from surface deformation, to thermal anomalies, gas fluxes and eruptive plumes. Many of the papers take a broad perspective, reviewing current techniques and applications, or demonstrating the potential to investigate volcano behaviour and volcanic activity at regional to global scales.  Papers in the volume also show the ways in which people are now trying to go from these observations to a deeper understanding of underlying processes, by integrating observations with theoretical models and computer simulations of volcano behaviour; and then to use these insights to advance the potential for eruption forecasting. We hope that this Special Publication will find a wide and appreciative audience out there!

An illustration of some of the applications of remote-sensing techniques to a volcano during a hypothetical eruption cycle.

An illustration of some of the applications of remote-sensing techniques to a volcano through a hypothetical eruption cycle, across wavelengths ranging from the Infrared (I.R.), through the Visible (Vis.) and Ultraviolet (U.V.), to radar (ca. 2.5 – 30 cm in volcanic applications). Earth Observation (EO) techniques now allow the detection and analysis of a spectrum of different aspects of volcano behaviour at both non-erupting and  erupting volcanoes. From the introduction to the Geological Society Special Publication 380 (Pyle et al., 2013).  The seismic event rate trace is schematic, but based on observations at Mt St Helens in March – May 1980. 


Editing a volume of this scale requires a lot of support from a lot of people. On behalf  of the editors (Tamsin Mather, Juliet Biggs and myself), we would like to thank the authors of all of the contributions for their hard work and for entrusting their manuscripts with us; we would like to thank the very many reviewers who selflessly gave up their time to provide the feedback and constructive criticism of the papers that is the key part of the peer-review process; and we would also like to thank the staff of the Geological Society’s Publishing House, and in particular Angharad Hills, Tamzin Anderson and Hannah Sime, who shepherded this v0lume from start to finish, and who have turned our initial idea into such a wonderful physical volume. Finally, and on behalf of all of the authors, we would like to acknowledge the many individuals, institutions and agencies who have provided the facilities, funding, imagery and datasets which have underpinned all of this work.


Pyle DM, Mather TA, Biggs J (eds) 2013. Remote sensing of Volcanoes and Volcanic Processes: Integrating Observation and Modelling. Geological Society, London, Special Publications, 380. ISBN 978-1-86239-362-2.

The volume is available to subscribers through the Geological Society’s Lyell Collection, and can be purchased via the Geological Society’s online Bookshop.

Abbreviated contents list (the full list is available via the Lyell collection):

Pyle, DM et al. – Remote sensing of volcanoes and volcanic processes: integrating observation and modelling – introduction (Free content)

Ebmeier, SK et al. – Applicability of InSAR to tropical volcanoes

Wauthier, C et al. – Nyamulagira’s magma plumbing system inferred from 15 years of InSAR

Aoki, Y et al. – Magma pathway and its structural controls at Asama volcano, Japan

Segall, P – Volcano deformation and eruption forecasting

Blackett, M – Review of the utility of infrared remote sensing for detecting and monitoring volcanic activity

Zaksek, K et al. – Constraining the uncertainties of volcano thermal anomaly monitoring using a Kalman filter technique

Jay, JA et al. – Volcanic hotspots of the central and southern Andes as seen from space by ASTER and MODVOLC, 2000 – 2010

van Manen, S et al. – Forecasting large explosions at Bezymianny volcano using thermal satellite data.

Hutchison, W et al. – Airborne thermal remote sensing of the Volcan de Colima lava dome from 2007-2010

Carn, SA et al. – Measuring global volcanic degassing with the Ozone Monitoring Instrument

McCormick, BT et al. – Volcano monitoring applications of the Ozone Monitoring Instrument

Grainger, RG et al. – Measuring volcanic plume and ash properties from space

Pieri, D et al. – In situ observations and sampling of volcanic emissions with NASA and UCR unmanned aircraft