AGW Observer

Observations of anthropogenic global warming

Papers on volcanoes and climate

Posted by Ari Jokimäki on September 29, 2010

This is a list of papers on the climate effects of volcanoes. The list is not complete, and will most likely be updated in the future in order to make it more thorough and more representative.

Volcanoes and climate – Cole-Dai (2010) A review article “Of the natural forcings causing short-term climatic variations, volcanism, along with its climatic impact, is perhaps the best understood. The primary net result of the impact is the reduced receipt of solar energy at Earth’s surface due to the scattering of incoming solar radiation by secondary sulfate aerosols formed from volcanic sulfur. The quantitative effects can be measured in energy-balance-based climate models, which require validation using high-quality paleoclimatic and paleovolcanic data. An important advancement in the effort to understand the role of volcanism in climate change in the recent decade is the significant improvement in paleovolcanic records from polar ice cores, represented by long records with unprecedented temporal accuracy and precision, and by the potential to identify climate-impacting stratospheric eruptions in the records. Other improvements include (1) the investigation of long-term relationship between eruptions (including super-eruptions) and climate variations, beyond an eruption’s radiative impact of up to a few years; (2) a better understanding of the response to volcanic perturbation of feedback mechanisms in the climate system; and (3) the limited role of volcanic eruptions in the era of human-induced greenhouse warming. Urgent research/investigation is needed to evaluate the geoengineering proposition to counteract greenhouse warming by injecting sulfur dioxide into the stratosphere, which is based on the significant cooling effects of stratospheric volcanic eruptions, and its serious unintended consequences.” Jihong Cole-Dai, Wiley Interdisciplinary Reviews: Climate Change, 2010, DOI: 10.1002/wcc.76. [Full text]

Climate response to large, high-latitude and low-latitude volcanic eruptions in the Community Climate System Model – Schneider et al. (2009) “Explosive volcanism is known to be a leading natural cause of climate change. The second half of the 13th century was likely the most volcanically perturbed half-century of the last 2000 years, although none of the major 13th century eruptions have been clearly attributed to specific volcanoes. This period was in general a time of transition from the relatively warm Medieval period to the colder Little Ice Age, but available proxy records are insufficient on their own to clearly assess whether this transition is associated with volcanism. This context motivates our investigation of the climate system sensitivity to high- and low-latitude volcanism using the fully coupled NCAR Community Climate System Model (CCSM3). We evaluate two sets of ensemble simulations, each containing four volcanic pulses, with the first set representing them as a sequence of tropical eruptions and the second representing eruptions occurring in the mid-high latitudes of both the Northern and Southern hemispheres. The short-term, direct radiative impacts of tropical and high-latitude eruptions include significant cooling over the continents in summer and cooling over regions of increased sea-ice concentration in Northern Hemisphere (NH) winter. A main dynamical impact of moderate tropical eruptions is a winter warming pattern across northern Eurasia. Furthermore, both ensembles show significant reductions in global precipitation, especially in the summer monsoon regions. The most important long-term impact is the cooling of the high-latitude NH produced by multiple tropical eruptions, suggesting that positive feedbacks associated with ice and snow cover could lead to long-term climate cooling in the Arctic.” Schneider, D. P., C. M. Ammann, B. L. Otto-Bliesner, and D. S. Kaufman (2009), J. Geophys. Res., 114, D15101, doi:10.1029/2008JD011222.

Bipolar correlation of volcanism with millennial climate change – Bay et al. (2004) “Analyzing data from our optical dust logger, we find that volcanic ash layers from the Siple Dome (Antarctica) borehole are simultaneous (with >99% rejection of the null hypothesis) with the onset of millennium-timescale cooling recorded at Greenland Ice Sheet Project 2 (GISP2; Greenland). These data are the best evidence yet for a causal connection between volcanism and millennial climate change and lead to possibilities of a direct causal relationship. Evidence has been accumulating for decades that volcanic eruptions can perturb climate and possibly affect it on long timescales and that volcanism may respond to climate change. If rapid climate change can induce volcanism, this result could be further evidence of a southern-lead North–South climate asynchrony. Alternatively, a volcanic-forcing viewpoint is of particular interest because of the high correlation and relative timing of the events, and it may involve a scenario in which volcanic ash and sulfate abruptly increase the soluble iron in large surface areas of the nutrient-limited Southern Ocean, stimulate growth of phytoplankton, which enhance volcanic effects on planetary albedo and the global carbon cycle, and trigger northern millennial cooling. Large global temperature swings could be limited by feedback within the volcano–climate system.” Ryan C. Bay, Nathan Bramall, and P. Buford Price, PNAS April 27, 2004 vol. 101 no. 17 6341-6345, doi: 10.1073/pnas.0400323101. [Full text]

Volcanic eruption frequency over the last 45 ky as recorded in Epica-Dome C ice core (East Antarctica) and its relationship with climatic changes – Castellano et al. (2004) “The sulphate glacio-chemical profiles constitute a reliable proxy marker for reconstruction of past volcanic history, assuming a reliable method to distinguish sulphate spikes and to evaluate the flux of individual events is set up. The resulting volcanic event profile is used to reconstruct past event frequencies, and to investigate possible links between volcanism and climatic changes. Volcanic event signatures are useful also in comparing time scales from ice cores drilled at different locations. In this paper, a new method to pick out volcanic signals is proposed. It improves on methods based on the calculation of a threshold using a general mean value plus a multiple of the standard deviation by adding: (1) quantification of nonvolcanic sulphate contributions; (2) sulphate fluxes, instead of concentrations, accounting for accumulation rate changes; (3) data treatment using a log-normal statistic, instead of a Gaussian-type distribution, to take into account the real sulphate distribution; (4) a smoothed curve (weighted fitting) to better understand the residual variability of the sulphate background. This method is used to detect volcanic events throughout the 45 ky time span of the EDC96 ice core, drilled at Dome C on the East Antarctic plateau. A total of 283 volcanic signatures are recovered, with a mean of 6.3 events per millennium. The temporal event frequencies indicate that the last 2000 years were probably characterized by the highest volcanic activity in the period covered by the core and that there is no clear link between number of events recorded and climatic changes.” E. Castellano, S. Becagli, J. Jouzel, A. Migliori, M. Severi, J. P. Steffensen, R. Traversi and R. Udisti, Global and Planetary Change, Volume 42, Issues 1-4, July 2004, Pages 195-205, doi:10.1016/j.gloplacha.2003.11.007.

Volcanic and Solar Forcing of Climate Change during the Preindustrial Era – Shindell et al. (2003) “The climate response to variability in volcanic aerosols and solar irradiance, the primary forcings during the preindustrial era, is examined in a stratosphere-resolving general circulation model. The best agreement with historical and proxy data is obtained using both forcings, each of which has a significant effect on global mean temperatures. However, their regional climate impacts in the Northern Hemisphere are quite different. While the short-term continental winter warming response to volcanism is well known, it is shown that due to opposing dynamical and radiative effects, the long-term (decadal mean) regional response is not significant compared to unforced variability for either the winter or the annual average. In contrast, the long-term regional response to solar forcing greatly exceeds unforced variability for both time averages, as the dynamical and radiative effects reinforce one another, and produces climate anomalies similar to those seen during the Little Ice Age. Thus, long-term regional changes during the preindustrial appear to have been dominated by solar forcing.” Shindell, Drew T., Gavin A. Schmidt, Ron L. Miller, Michael E. Mann, 2003, J. Climate, 16, 4094–4107. [Full text]

Volcanic eruptions and climate – Robock (2000) A review article. “Volcanic eruptions are an important natural cause of climate change on many timescales. A new capability to predict the climatic response to a large tropical eruption for the succeeding 2 years will prove valuable to society. In addition, to detect and attribute anthropogenic influences on climate, including effects of greenhouse gases, aerosols, and ozone-depleting chemicals, it is crucial to quantify the natural fluctuations so as to separate them from anthropogenic fluctuations in the climate record. Studying the responses of climate to volcanic eruptions also helps us to better understand important radiative and dynamical processes that respond in the climate system to both natural and anthropogenic forcings. Furthermore, modeling the effects of volcanic eruptions helps us to improve climate models that are needed to study anthropogenic effects. Large volcanic eruptions inject sulfur gases into the stratosphere, which convert to sulfate aerosols with an e-folding residence time of about 1 year. Large ash particles fall out much quicker. The radiative and chemical effects of this aerosol cloud produce responses in the climate system. By scattering some solar radiation back to space, the aerosols cool the surface, but by absorbing both solar and terrestrial radiation, the aerosol layer heats the stratosphere. For a tropical eruption this heating is larger in the tropics than in the high latitudes, producing an enhanced pole-to-equator temperature gradient, especially in winter. In the Northern Hemisphere winter this enhanced gradient produces a stronger polar vortex, and this stronger jet stream produces a characteristic stationary wave pattern of tropospheric circulation, resulting in winter warming of Northern Hemisphere continents. This indirect advective effect on temperature is stronger than the radiative cooling effect that dominates at lower latitudes and in the summer. The volcanic aerosols also serve as surfaces for heterogeneous chemical reactions that destroy stratospheric ozone, which lowers ultraviolet absorption and reduces the radiative heating in the lower stratosphere, but the net effect is still heating. Because this chemical effect depends on the presence of anthropogenic chlorine, it has only become important in recent decades. For a few days after an eruption the amplitude of the diurnal cycle of surface air temperature is reduced under the cloud. On a much longer timescale, volcanic effects played a large role in interdecadal climate change of the Little Ice Age. There is no perfect index of past volcanism, but more ice cores from Greenland and Antarctica will improve the record. There is no evidence that volcanic eruptions produce El Niño events, but the climatic effects of El Niño and volcanic eruptions must be separated to understand the climatic response to each.” Robock, A. (2000), Rev. Geophys., 38(2), 191–219, doi:10.1029/1998RG000054. [Full text]

Radiative forcing from the 1991 Mount Pinatubo volcanic eruption – Stenchikov et al. (1998) “Volcanic sulfate aerosols in the stratosphere produce significant long-term solar and infrared radiative perturbations in the Earth’s atmosphere and at the surface, which cause a response of the climate system. Here we study the fundamental process of the development of this volcanic radiative forcing, focusing on the eruption of Mount Pinatubo in the Philippines on June 15, 1991. We develop a spectral-, space-, and time-dependent set of aerosol parameters for 2 years after the Pinatubo eruption using a combination of SAGE II aerosol extinctions and UARS-retrieved effective radii, supported by SAM II, AVHRR, lidar and balloon observations. Using these data, we calculate the aerosol radiative forcing with the ECHAM4 general circulation model (GCM) for cases with climatological and observed sea surface temperature (SST), as well as with and without climate response. We find that the aerosol radiative forcing is not sensitive to the climate variations caused by SST or the atmospheric response to the aerosols, except in regions with varying dense cloudiness. The solar forcing in the near infrared contributes substantially to the total stratospheric heating. A complete formulation of radiative forcing should include not only changes of net fluxes at the tropopause but also the vertical distribution of atmospheric heating rates and the change of downward thermal and net solar radiative fluxes at the surface. These forcing and aerosol data are available for GCM experiments with any spatial and spectral resolution.” Stenchikov, G. L., I. Kirchner, A. Robock, H.-F. Graf, J. C. Antuña, R. G. Grainger, A. Lambert, and L. Thomason (1998), J. Geophys. Res., 103(D12), 13,837–13,857, doi:10.1029/98JD00693.

Modelling the distal impacts of past volcanic gas emissions. Evidence of Europe-wide environmental impacts from gases emitted during the eruption of Italian and Icelandic volcanoes in 1783 – Grattan et al. (1998) “This paper investigates the impact of volcanogenic aerial pollution upon the European environnement. Focusing on the year 1783 it is reavealed that a Europe-wide toxic fog, composed of volcagenic gases and aerosols caused respiratory illness, crop damage, panic and extreme weather. It is proposed that similar events may have occured in the past and should be considered as an agent of change by archaeologists and historians.” J Grattan, M Brayshay, J Sadler, Quaternaire, 1998, vol. 9, no 1 (75 p.) (1 p.1/4), pp. 25-35. [Full text available in abstract page]

A 110,000-Yr Record of Explosive Volcanism from the GISP2 (Greenland) Ice Core – Zielinski et al. (1996) “The time series of volcanically produced sulfate from the GISP2 ice core is used to develop a continuous record of explosive volcanism over the past 110,000 yr. We identified 850 volcanic signals (700 of these from 110,000 to 9000 yr ago) with sulfate concentrations greater than that associated with historical eruptions from either equatorial or mid-latitude regions that are known to have perturbed global or Northern Hemisphere climate, respectively. This number is a minimum because decreasing sampling resolution with depth, source volcano location, variable circulation patterns at the time of the eruption, and post-depositional modification of the signal can result in an incomplete record. The largest and most abundant volcanic signals over the past 110,000 yr, even after accounting for lower sampling resolution in the earlier part of the record, occur between 17,000 and 6000 yr ago, during and following the last deglaciation. A second period of enhanced volcanism occurs 35,000–22,000 yr ago, leading up to and during the last glacial maximum. These findings further support a possible climate-forcing component in volcanism. Increased volcanism often occurs during stadial/interstadial transitions within the last glaciation, but this is not consistent over the entire cycle. Ages for some of the largest known eruptions 100,000–9000 yr ago closely correspond to individual sulfate peaks or groups of peaks in our record.” Gregory A. Zielinski, Paul A. Mayewski, L. David Meeker, S. Whitlow and Mark S. Twickler, Quaternary Research, Volume 45, Issue 2, March 1996, Pages 109-118, doi:10.1006/qres.1996.0013.

Potential climate impact of Mount Pinatubo eruption – Hansen et al. (1992) “We use the GISS global climate model to make a preliminary estimate of Mount Pinatubo’s climate impact. Assuming the aerosol optical depth is nearly twice as great as for the 1982 El Chichon eruption, the model forecasts a dramatic but temporary break in recent global warming trends. The simulations indicate that Pinatubo occurred too late in the year to prevent 1991 from becoming one of the warmest years in instrumental records, but intense aerosol cooling is predicted to begin late in 1991 and to maximize late in 1992. The predicted cooling is sufficiently large that by mid 1992 it should even overwhelm global warming associated with an El Nino that appears to be developing, but the El Nino could shift the time of minimum global temperature into 1993. The model predicts a return to record warm levels in the later 1990s. We estimate the effect of the predicted global cooling on such practical matters as the severity of the coming Soviet winter and the dates of cherry blossoming next spring, and discuss caveats which must accompany these preliminary simulations.” Hansen, J., A. Lacis, R. Ruedy, and M. Sato (1992), Geophys. Res. Lett., 19(2), 215–218, doi:10.1029/91GL02788. [Full text]

Volcanic winter and accelerated glaciation following the Toba super-eruption – Rampino & Self (1992) “THE eruption of Toba in Sumatra 73,500 years ago was the largest known explosive volcanic event in the late Quaternary1. It could have lofted about 1015 g each of fine ash and sulphur gases to heights of 27–37 km, creating dense stratospheric dust and aerosol clouds. Here we present model calculations that investigate the possible climatic effects of the volcanic cloud. The increase in atmospheric opacity might have produced a ‘volcanic winter’2—a brief, pronounced regional and perhaps hemispheric cooling caused by the volcanic dust—followed by a few years with maximum estimated annual hemispheric surface-temperature decreases of 3–5 °C. The eruption occurred during the stage 5a-4 transition of the oxygen isotope record, a time of rapid ice growth and falling sea level3. We suggest that the Toba eruption may have greatly accelerated the shift to glacial conditions that was already underway, by inducing perennial snow cover and increased sea-ice extent at sensitive northern latitudes. As the onset of climate change may have helped to trigger the eruption itself4, we propose that the Toba event may exemplify a more general climate–volcano feedback mechanism.” Michael R. Rampino & Stephen Self, Nature 359, 50 – 52 (03 September 1992); doi:10.1038/359050a0.

The Great Tambora Eruption in 1815 and Its Aftermath – Stothers (1984) “Quantitative analytical methods are used to reconstruct the course of events during and after the cataclysmic eruption of Mount Tambora, Indonesia, on 10 and 11 April 1815. This was the world’s greatest ash eruption (so far as is definitely known) since the end of the last Ice Age. This synthesis is based on data and methods from the fields of volcanology, oceanography, glaciology, meteorology, climatology, astronomy, and history.” Richard B. Stothers, Science 15 June 1984: Vol. 224. no. 4654, pp. 1191 – 1198, DOI: 10.1126/science.224.4654.1191.

The Mount St. Helens Volcanic Eruption of 18 May 1980: Minimal Climatic Effect – Robock (1981) “An energy-balance numerical climate model was used to simulate the effects of the Mount St. Helens volcanic eruption of 18 May 1980. The resulting surface temperature depression is a maximum of 0.1°C in the winter in the polar region, but is an order of magnitude smaller than the observed natural variability from other effects and will therefore be undetectable.” Alan Robock, Science 19 June 1981: Vol. 212. no. 4501, pp. 1383 – 1384, DOI: 10.1126/science.212.4501.1383.

Perturbation of the zonal radiation balance by a stratospheric aerosol layer – Harshvardhan (1979) “The effect of stratospheric aerosols on the earth’s monthly zonal radiation balance is investigated using a model layer consisting of 75% H2SO4, the primary constituent of the background aerosol layer. The reduction in solar energy absorbed by the earth-atmosphere system is determined through the albedo sensitivity, and the optically thin approximation is used in conjunction with the Henyey-Greenstein phase function for scattering. An infrared radiative transfer model is used to estimate the increased greenhouse effect from the aerosol layer, and the infrared heating compensates for the albedo effect in altering the radiation balance. The results indicate that the dominant influence of the thin model stratospheric aerosol layer is an increased reflection of solar energy all over the globe except for the polar-winter region, but the change in the radiation balance is uniform and small equatorward of 50 deg.” Harshvardhan, M. R., Journal of the Atmospheric Sciences. Vol. 36, pp. 1274-1285. July 1979.

Volcanic Explosions and Climatic Change: A Theoretical Assessment – Pollack et al. (1976) “Volcanic explosions introduce silicate dust particles and sulfur gases into the stratosphere. The sulfur gases are slowly converted to sulfuric acid particles. We have performed radiative transfer calculations at visible and infrared wavelengths to determine the effect of these aerosols on the global energy budget. A numerical method that allows for the vertical inhomogeneity of the atmosphere and that permits an accurate solution of the multiple scattering problem is used to determine the variation of the global albedo with stratospheric aerosol burden. These results are employed together with a calculation of the thermal radiation at the top of the atmosphere to determine the net change in mean surface temperature. Both calculations use measured optical constants for the aerosol species of interest. We find that increases in both silicate and sulfuric acid aerosols lead to an increase in the global albedo. However, this cooling is offset by the enhanced greenhouse warming due to the aerosol opacity at infrared wavelengths. During the first few months following a volcanic explosion, when the aerosols are mostly dust grains of fairly large diameter, the two effects either cancel out or a small net warming of the surface occurs, accompanied by an increase in stratospheric temperatures. Our calculations indicate that the observed heating of the stratosphere following the eruption of Mt. Agung was due chiefly to the absorption of upwelling terrestrial radiation by the added particles. However, at later times, and during most of the posteruption period, smaller sized dust and sulfuric acid aerosol particles caused a net cooling. The integrated effect over all stages following a volcanic eruption is a net cooling of the surface. Our calculations yield an estimate of the globally averaged temperature change caused by a given level of volcanic activity. A study of observed levels of volcanic activity suggests that observed climatic changes may be caused directly by single and especially by multiple volcanic explosions.” Pollack, J. B., O. B. Toon, C. Sagan, A. Summers, B. Baldwin, and W. Van Camp (1976), J. Geophys. Res., 81(6), 1071–1083, doi:10.1029/JC081i006p01071.

Volcanic Dust in the Atmosphere; with a Chronology and Assessment of Its Meteorological Significance – Lamb (1970) “After defining the terms commonly used in reporting volcanic eruptions and noting previous approaches to assessment of their magnitudes, this study proceeds to examine aspects of importance, or possible importance, to meteorology-principally the dust veils created in the atmosphere, particle sizes and distribution, heights, fall speeds and atmospheric residence times. Later sections deal with spread of the dust by the atmospheric circulation and the direct effects apparent upon radiation, surface temperature and extent of ice in the polar regions. These effects, as well as various crude measures of the total quantity of solid matter thrown up, are used to arrive at numerical assessments of volcanic eruptions in terms of a dust veil index (d.v.i.). The latitude of origin of the dust (latitude of the volcano) receives some attention, and apparently affects the course of development of the atmospheric circulation over the three or four years following, at least in the case of great eruptions (d.v.i. > 100 over one hemisphere). Effects upon the extent of ice on the polar seas may be of somewhat longer duration, and thereby influence the atmospheric circulation over a longer period of years, since there seems to be some association with the cumulative d.v.i. values when successive great eruptions occur with only few years between. The time distribution of volcanic dust since the last Ice Age, and since A.D. 1500, are indicated in as much detail as the evidence permits. Some associations with changes of climate are suggested, but it is clear that volcanic dust is not the only, and probably not the main, influence in this. The appendices give a chronology of eruptions (including those which it seems possible to dismiss as regards any effect on world weather or climate) and a chronology of d.v.i. values. A third appendix displays by means of graphs the variation of some circulation parameters in January and July in the region of northwest Europe over the years immediately following forty of the greatest eruptions since 1680.” H. H. Lamb, Phil. Trans. R. Soc. Lond. A 2 July 1970 vol. 266 no. 1178 425-533, doi: 10.1098/rsta.1970.0010.

Recent secular changes of the global temperature – Mitchell (1961) As described by Robock (2000): “Mitchell [1961] was the first to conduct a superposed epoch analysis, averaging the effects of several eruptions to isolate the volcanic effect from other presumably random fluctuations. He only looked at 5-year average periods, however, and did not have a very long temperature record.” Mitchell, J. M., Jr., Ann. N. Y. Acad. Sci., 95, 235–250, 1961.

Volcanic dust and other factors in the production of climatic changes, and their possible relation to ice gases – Humphreys (1913) As described by Robock (2000): “Humphreys [1913, 1940] associated cooling events after large volcanic eruptions with the radiative effects of the stratospheric aerosols but did not have a sufficiently long or horizontally extensive temperature database to quantify the effects.” Humphreys, W. J., J. Franklin Inst., Aug., 131–172, 1913.

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