title: Volcano-induced regime shifts in millennial tree-ring chronologies from northeastern North America.
abstract: Dated records of ice-cap growth from Arctic Canada recently suggested that a succession of strong volcanic eruptions forced an abrupt onset of the Little Ice Age between A.D. 1275 and 1300 [Miller GH, et al. (2012) Geophys Res Lett 39(2):L02708, 10.1029/2011GL050168]. Although this idea is supported by simulation experiments with general circulation models, additional support from field data are limited. In particular, the Northern Hemisphere network of temperature-sensitive millennial tree-ring chronologies, which principally comprises Eurasian sites, suggests that the strongest eruptions only caused cooling episodes lasting less than about 10 y. Here we present a new network of millennial tree-ring chronologies from the taiga of northeastern North America, which fills a wide gap in the network of the Northern Hemisphere's chronologies suitable for temperature reconstructions and supports the hypothesis that volcanoes triggered both the onset and the coldest episode of the Little Ice Age. Following the well-expressed Medieval Climate Anomaly (approximately A.D. 910-1257), which comprised the warmest decades of the last millennium, our tree-ring-based temperature reconstruction displays an abrupt regime shift toward lower average summer temperatures precisely coinciding with a series of 13th century eruptions centered around the 1257 Samalas event and closely preceding ice-cap expansion in Arctic Canada. Furthermore, the successive 1809 (unknown volcano) and 1815 (Tambora) eruptions triggered a subsequent shift to the coldest 40-y period of the last 1100 y. These results confirm that series of large eruptions may cause region-specific regime shifts in the climate system and that the climate of northeastern North America is especially sensitive to volcanic forcing.
authors: Département de Biologie, Chimie et Géographie, Centre d'Études Nordiques, Université du Québec à Rimouski, Rimouski, QC, Canada G5L 3A1; Fabio.Gennaretti@uqar.ca.
authors: Fabio
authors: F
authors: Gennaretti
authors: Département de Biologie, Chimie et Géographie, Centre d'Études Nordiques, Université du Québec à Rimouski, Rimouski, QC, Canada G5L 3A1;
authors: Dominique
authors: D
authors: Arseneault
authors: Aix-Marseille Université, Fédération de recherche (CNRS-3098) Ecosystèmes Continentaux et Risques Environnementaux, F-13545 Aix-en-Provence, France;
authors: Antoine
authors: A
authors: Nicault
authors: Expertise Mécanique, Métallurgie et Hydro-Éolien, Institut de Recherche d'Hydro-Québec, Varennes, QC, Canada J3X 1S1; and.
authors: Luc
authors: L
authors: Perreault
authors: Centre Eau Terre Environnement, Institut National de la Recherche Scientifique, Québec, QC, Canada G1K 9A9.
authors: Yves
authors: Y
authors: Bégin
mesh_terms: D002170:Canada; D057231:Climate Change; D008954:Models, Biological; D014197:Trees; D018707:Volcanic Eruptions
keywords: Picea mariana; black spruce; dendroclimatology; lake subfossil trees; temperature regime shifts