Tree-ring Evidence For Environmental Disasters During The Bronze Age: Causes And Effects

Abstract of talk by Mike G L Baillie

Palaeoecology Centre, School of Geosciences, Queen's University, Belfast, Northern Ireland. e-mail: mbaillie[at]
Presented at the SIS Conference: Natural Catastrophes during Bronze Age Civilisations (11th-13th July 1997)

In 1988 the observation was made that narrowest-ring events in Irish sub-fossil oak chronologies appeared to line up with large acidities in the Greenland ice records from Camp Century and Dye3. Three of the events, at tree-ring ages 2345 BC, 1628 BC and 1159 BC turned out to be of particular interest as they contributed to debates on the Hekla 4 eruption in Iceland, dated to 2310±20 CalBC, Santorini in the Aegean, dated to circa 1670-1530 CalBC, and, possibly, Hekla 3, linked by Hammer and colleagues to their 1120±30 BC acid layer. It quickly became apparent, most notably through comments from Kevin Pang, that the two later events might relate in some way to the start and end of the Chinese Shang dynasty. It is equally of interest that the Egyptian New Kingdom traditionally spans the approximate range 1570 to 1080 BC. So the question arose whether these two volcano-related events could have caused widespread dynastic change. In order to proceed with this debate it is necessary to attempt to get a better handle on the nature of the effects. This paper will look at information from American and Fennoscandian tree-ring records and make some attempt to define the nature of the 1628 BC and 1159 BC events; are they truly abrupt, as would be expected with volcanoes, or are they imposed on pre-existing downturns. Existing exidence suggests that the latter may be the case. If this is correct, it seems appropriate to ask what might have caused the downturns? This question leads logically to the speculation that loading of the atmosphere from space might be a significant factor in the environmental downturns.

MIKE BAILLIE is a professor in the Palaeoecology Centre, School of Geosciences, Queen's University, Belfast, N. Ireland. After reading physics at Queen's he moved into Archaeology and Palaeoecology taking a particular interest in chronology. His specialism is dendrochronology, and he has been involved in the construction of some of the first, long, oak chronologies. Using information from tree-ring records, he has attempted to identify abrupt environmental downturns in the past and to demonstrate their effects on past human populations. He publishes widely on these and related topics and is the author of A Slice Through Time: dendrochronology and precision dating (London: Routledge 1995).