Kutterolf, Steffen , Hansteen, Thor , Appel, K., Freundt, Armin , Krüger, Kirstin, Peréz Fern´andez, Wendy and Wehrmann, Heidi (2012) Bromine in Plininan eruptions: A paleo-ozone killer?. [Talk] In: The Lübeck Retreat, Collaborative Research SFB 574 Volatiles and Fluids in Subduction Zones: Climate Feedback and Trigger Mechanisms for Natural Disasters. , 23.-25.05.2012, Lübeck . The Lübeck Retreat: final colloquium of SFB 574; May 23-25, 2012: program & abstracts. ; p. 16 .

Abstract

Large explosive volcanic eruptions inject gases, aerosols and fine ash into the stratosphere, potentially influencing climate. Emissions of chlorine (Cl) and bromine (Br) from large eruptions play an important role for catalytic destruction of ozone in the stratosphere, but hitherto the effects of volcanic Br release with respect to an extended pre-historic time series is not known on a regional or global scale.
The bromine release from 31 large explosive eruptions in Central America covering the last 200 ka and a whole subduction zone was determined with the petrologic method. Melt inclusions in volcanic minerals were analyzed using a new optimized synchrotron radiation X-ray fluorescence microprobe set-up. The eruptions produced Br outputs of 1 to 1100 kt per event, resulting in an average Br emission of 127 kt per eruption, which, together with Chlorine, would increase the Equivalent Effective Stratospheric Chlorine (EESC) up to 600% of the pre-industrial stratospheric concentration if only 10% of the emitted halogens reach the stratosphere. Based on our estimated Central American Br and Cl loading to the stratosphere, we conclude that, in contrast to the general opinion until now, many large tropical volcanic eruptions had and have the potential to substantially deplete ozone on a
global scale, eventually forming (pre-industrial) ozone holes.

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