Clim. Past, 11, 105–114, 2015 www.clim-past.net/11/105/2015/ doi:10.5194/cp-11-105-2015 © Author(s) 2015. CC Attribution 3.0 License. Tree ring effects and ice core acidities clarify the volcanic record of the first millennium M. G. L. Baillie1 and J. McAneney2 1School of Geography, Archaeology and Palaeoecology, Elmwood Avenue, Queen’s University, Belfast, Belfast BT7 1NN, Northern Ireland, UK 2Independent Researcher, Bangor, Northern Ireland, UK Correspondence to: M. G. L. Baillie (
[email protected]) Received: 28 February 2014 – Published in Clim. Past Discuss.: 15 April 2014 Revised: 8 December 2014 – Accepted: 12 December 2014 – Published: 16 January 2015 Abstract. In 2012 Plummer et al., in presenting the volcanic 1 Background chronology of the Antarctic Law Dome ice core, chose to list connections to acid layers in other ice cores and also Large explosive volcanic eruptions can induce hemispheric, possible chronological coincidences between ice acid dates and occasionally global, environmental effects through the and the precise dates of frost damage, and/or reduced growth injection of sulfate aerosols into the stratosphere altering the in North American bristlecone pines. We disagree with the absorption and reflection of solar radiation within the atmo- chronological links indicated by Plummer et al. for the period sphere, producing an overall cooling effect on global climate before AD 700, and in this paper we show that a case can be (Rampino and Self, 1982). Attempts to trace the areal ex- made that better linkages between ice acid and tree ring ef- tent of such environmental effects rely mostly on evidence fects occur for this period if the ice chronologies are system- of tree growth response to climate derived from precisely atically moved forward by around 7 years, consistent with a dated tree ring chronologies.