Oxygen-isotope records from Greenland ice cores 1,2 indicate numerous rapid climate¯uctuations during the last glacial period. North Atlantic marine sediment cores show comparable variability in sea surface temperature and the deposition of icerafted debris 3±5 . In contrast, very few continental records of this time period provide the temporal resolution and environmental sensitivity necessary to reveal the extent and effects of these environmental¯uctuations on the continents. Here we present high-resolution geochemical, physical and pollen data from lake sediments in Italy and from a Mediterranean sediment core, linked by a common tephrochronology. Our lacustrine sequence extends to the past 102,000 years. Many of its features correlate well with the Greenland ice-core records, demonstrating that the closely coupled ocean±atmosphere system of the Northern Hemisphere during the last glacial 4 extended its in¯uence at least as far as the central Mediterranean region. Numerous vegetation changes were rapid, frequently occurring in less than 200 years, showing that the terrestrial biosphere participated fully in lastglacial climate variability. Earlier than 65,000 years ago, our record shows more climate¯uctuations than are apparent in the Greenland ice cores. Together, the multi-proxy data from the continental and marine records reveal differences in the seasonal character of climate during successive interstadials, and provide a step towards determining the underlying mechanisms of the centennial±millennial-scale variability.A series of four sediment cores (B, D, J and L) obtained from Lago Grande di Monticchio (408 569 N, 158 359 E, 656 m above sea level), a maar lake in Basilicata, southern Italy, extends to a depth of 72.5 m. Sedimentation rates, estimated from annually laminated sections of a composite of these cores, provide a chronology 6,7 that gives a date of 101.7 kyr ago for the base of the record (Fig. 1). This calendaryear chronology, based solely upon Monticchio sedimentation rates, is independent of palynostratigraphic (that is, pollen-based), marine d 18 O event or ice-core interstadial correlations. It is complemented by a tephrochronology and a series of radioisotopic ages.

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Impacts of global climate change on terrestrial ecosystems are imperfectly constrained by ecosystem models and direct observations. Pervasive ecosystem transformations occurred in response to warming and associated climatic changes during the last glacial-to-interglacial transition, which was comparable in magnitude to warming projected for the next century under high-emission scenarios. We reviewed 594 published paleoecological records to examine compositional and structural changes in terrestrial vegetation since the last glacial period and to project the magnitudes of ecosystem transformations under alternative future emission scenarios. Our results indicate that terrestrial ecosystems are highly sensitive to temperature change and suggest that, without major reductions in greenhouse gas emissions to the atmosphere, terrestrial ecosystems worldwide are at risk of major transformation, with accompanying disruption of ecosystem services and impacts on biodiversity.

Establishing phase relationships between earth-system components during periods of rapid global change is vital to understanding the underlying processes. It requires records of each component with independent and accurate chronologies. Until now, no continental record extending from the present to the penultimate glacial had such a chronology to our knowledge. Here, we present such a record from the annually laminated sediments of Lago Grande di Monticchio, southern Italy. Using this record we determine the duration (17.70 ؎ 0.20 ka) and age of onset (127.20 ؎ 1.60 ka B.P.) of the last interglacial, as reflected by terrestrial ecosystems. This record also reveals that the transitions at the beginning and end of the interglacial spanned only Ϸ100 and 150 years, respectively. Comparison with records of other earthsystem components reveals complex leads and lags. During the penultimate deglaciation phase relationships are similar to those during the most recent deglaciation, peaks in Antarctic warming and atmospheric methane both leading Northern Hemisphere terrestrial warming. It is notable, however, that there is no evidence at Monticchio of a Younger Dryas-like oscillation during the penultimate deglaciation. Warming into the first major interstadial event after the last interglacial is characterized by markedly different phase relationships to those of the deglaciations, warming at Monticchio coinciding with Antarctic warming and leading the atmospheric methane increase. Diachroneity is seen at the end of the interglacial; several global proxies indicate progressive cooling after Ϸ115 ka B.P., whereas the main terrestrial response in the Mediterranean region is abrupt and occurs at 109.50 ؎ 1.40 ka B.P.Eemian ͉ phase relationships ͉ pollen ͉ varves R econstructing the phase relationships between major earthsystem components relies on precise, accurate, and independent chronologies. However, absolute dating of geological records beyond the range of radiocarbon (more than Ϸ50 ka B.P.) is problematic, and age estimates for records of the last interglacial (LI) commonly rely on indirect dating approaches (1-4), often either by tuning to the time scale of orbital variations (2) or ''wiggle-matching'' to another record and applying its chronology (3, 4). Until now no continuous continental record extending from the present through the LI to the penultimate glacial had its own internal chronology to our knowledge. Thus timing and duration of the LI, as reflected in continental, marine, and ice-core records, and the phase relationships between these major earth-system components during marine oxygen isotope stage (MIS) 6-4, have been the subject of much debate (1, 5-9). Shackleton (9) first proposed correspondence between the LI and MIS 5e, whereas Woillard (10) subsequently demonstrated such apparent correspondence in a continental record. More recently, however, pollen, alkenone, and ␦ 18 O analyses of marine cores from locations close to the Iberian peninsula have shown asynchrony between changes in terrestrial veg...

The dating of depths in two or more cores is frequently followed by a study of the synchroneity or otherwise of events reflected in the cores. The difficulties most frequently encountered are: (a) determining precisely the depths associated with the events; and (b) determining the ages associated with the depths. There has been much progress in recent years in developing tools for the study of uncertainties in establishing chronologies. This has not yet been matched by similar progress in modelling event/depth relationships. This paper proposes a simple and flexible approach, showing how uncertain events can be married to uncertain chronologies.