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where changes are expected to be most extensive, so we need to place these projected changes in the context of past Arctic climate variability. We know, from large-scale studies of climate variability over the last century and the last millennium, and from model simulations, that temperature changes tend to be amplified at high latitudes-and this seems to be true both for the periods of 'natural' and of anthropogenic forcing (Moritz et al., 2002; Holland and Bitz, 2003; Arctic Climate Impacts Assessment (ACIA), 2005; see also the discussion at http://www.realclimate.org/index.php?p=234, last accessed 19 October 2007). Palaeoclimatic records from high latitudes may thus capture changes that have affected the hemisphere as a whole, whereas the record is more muted at lower latitudes. This polar amplification is related to feedbacks associated with

Few annually laminated (varved) lacustrine records exist in the Arctic, but these highresolution climate archives are needed to better understand abrupt climate change and the natural mode of climate variability of this sensitive region. This paper presents a new highresolution 2900-year long varved lake sediment record from the Fosheim Peninsula, Ellesmere Island. The varve chronology is based on multiple varve counts made on highresolution scanning electron microscope images of overlapping sediment thin sections, and is supported by several independent dating techniques, including 137 Cs and 210 Pb analysis, one optically stimulated luminescence age located close to the bottom of the composite sequence, and comparision between paleomagnetic variations of this record and the longest High-Arctic varve record, Lower Murray Lake, which confirms the reliability of the Sawtooth chronology. High resolution backscattered images examined under a scanning electron microscope (SEM) were crucial to giving a more detailed view of sedimentation processes in the lake and thus help to delineate varves more precisely than in conventional image analysis. Fine-scale geochemical analysis reveals that lake sedimentation is mainly clastic and that elemental geochemistry is influenced by grain-size. Principal component analysis of multiple proxies and the coarse grain-size fraction of South Sawtooth Lake display similar fluctuations to the nearby Agassiz Ice Cap ¶ 18 O record, including lower values during the Little Ice Age cold period. These results show this new high-resolution and continuous record has a reliable varve chronology and is sensitive to temperature variability. South Sawtooth Lake's mean sedimentation rate of 1.67 mm a -1 is higher than any other sedimentary sequence in the High Arctic providing a unique opportunity for extracting new, high-resolution paleoclimatological and paleoenvironmental record.

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[1] The annually-laminated (i.e., varved) sediment record from the Lower Mystic Lake (near Boston, MA), contains a series of anomalous graded beds deposited by strong flooding events that have affected the basin over the last millennium. From the historic portion of the record, 10 out of 11 of the most prominent graded beds correspond with years in which category 2 -3 hurricanes are known to have struck the Boston area. Thus, we conclude that the graded beds represent deposition related to intense hurricane precipitation combined with wind-driven vegetation disturbance that exposes fresh, loose sediment. The hurricane signal shows strong, centennial-scale variations in frequency with a period of increased activity between the 12th -16th centuries, and decreased activity during the 11th and 17th -19th centuries. These frequency changes are consistent with other paleoclimate indicators from the tropical North Atlantic, in particular, sea surface temperature variations. Citation: Besonen, M. R., R. S.Bradley, M. Mudelsee, M. B. Abbott, and P. Francus (2008), A 1,000-year, annually-resolved record of hurricane activity from