Raymond S Bradley

Datos Biográficos

ID327331
NOMBRERaymond S Bradley
NOMBRESRaymond S
APELLIDOBradley
FIRMABRADLEY R S
AFILIACIONESUniversity of Massachusetts Amherst
ORCID0000-0002-4032-9519
VERIFICADOSí
TOTAL DE OBRAS34
TOTAL DE CITAS64
TOTAL COMO AUTOR34
TOTAL COMO EDITOR0
PRIMER AÑO DE PUBLICACIÓN1972
AÑO MÁS RECIENTE DE PUBLICACIÓN2025
ÍNDICE H4

  • Sub-divisions of the Holocene

    Open AccessRaymond S BradleyARTICLEJournal of Geography (Chigaku…2025

    国際地質科学連合(IUGS)は,完新世を3つの階(ステージ)に区分し,階の境界を8200年B.P.と4200年B.P.と定義した。このような区分の根拠が再検討され,8200 B.P.を階の境界とするには十分な根拠があるものの,4200 B.P.の境界についてはそうとは言えない。4200 B.P.以降の期間を指すのにメガラヤン階(期)という用語を使用することは,世界的に重要な出来事の証拠が不十分であるため,正当化できない。国際層序委員会がメガラヤン階を定義した決定は撤回されるべきである

  • The steady loss – Palynological investigation into the main triggers of changes in vegetation and pastoral activity during the Norse period in southern Greenland

    Open AccessSascha Krüger, Tobias Schneider et al.ARTICLEQuaternary Environments and Humans2024

    Pastoral farming formed a key element of Norse subsistence strategies in South Greenland but with climatic changes of the Little Ice Age they may have reached their limit. Most recently, studies into hydrological changes across the Norse period (10th–15th century AD) revealed a severe drying trend that was coincident with the Norse demise during the early to mid-15th century AD. This study examines lake sediments from a central area of the Norse …

  • A Continuous Palynological Record of Forest Clearing at Rano Kao (Easter Island, SE Pacific) During the Last Millennium

    Open AccessIrantzu Seco, Valentí Rull et al.ARTICLEQuaternary2019

    Easter Island (Rapa Nui) deforestation has traditionally been viewed as a single event, synchronous in time and space across the island and caused by Polynesian settlers. However, recent studies have challenged this idea, introducing the concept of spatiotemporal heterogeneity and suggesting a role for climate change. This paper presents a continuous paleovegetation record of the last millennium (~960 to ~1710 CE), based on palynological analysis…

  • Testing the “tropical storm” hypothesis of Yucatan Peninsula climate variability during the Maya Terminal Classic Period

    Open AccessMartin Medina-Elizalde, Martín Medina‐Elizalde et al.ARTICLEQuaternary Research2016

    We examine the “tropical storm” hypothesis that precipitation variability in the Yucatan Peninsula (YP) was linked to the frequency of tropical cyclones during the demise of the Classic Maya civilization, in the Terminal Classic Period (TCP, AD 750—950). Evidence that supports the hypothesis includes: (1) a positive relationship between tropical storm frequency and precipitation amount over the YP today (proof of feasibility), (2) a statistically…

  • Implications arising from models of solar irradiance

    Open AccessRaymond S Bradley, Heinz Wanner et al.ARTICLEThe Holocene2016Referencias: 1

    Models of solar irradiance have been revised recently, leading to the current view that previous estimates of maximum total solar irradiance (TSI) in the 18th and 19th centuries were too low and should be adjusted upwards to be comparable with values in the 20th century. This adjustment is small (~0.03%) but implies a greater amplitude of irradiance change over recent centuries. This has no bearing on our concept of a Medieval Quiet Period

  • The Medieval Quiet Period

    Open AccessRaymond S Bradley, Heinz Wanner et al.ARTICLEThe Holocene2016Citada por: 6Referencias: 1

    For several centuries in early Medieval times the climate system was relatively unperturbed by natural forcing factors, resulting in a unique period of climate stability. We argue that this represents a reference state for the Common Era, well before anthropogenic forcing became the dominant driver of the climate system

  • A high-resolution 1200-year lacustrine record of glacier and climate fluctuations in Lofoten, northern Norway

    Open AccessPål Ringkjøb Nielsen, Nicholas L Balascio et al.ARTICLEThe Holocene2016Referencias: 46

    Here we present the first high-resolution late-Holocene glacier record from the Lofoten archipelago in northern Norway. The study is based on analyses of lacustrine sediments from the distal glacier-fed lake Kveitvikvatnet (30.1 m a.s.l.), as well as glacial-geomorphological mapping of the ~4.2-km 2 surrounding catchment. The lake sediment cores have been examined for input of glacial-derived sediments by using physical, geochemical and magnetic …

  • Biogeochemical evidence for hydrologic changes during the Holocene in a lake sediment record from southeast Greenland

    Open AccessNicholas L Balascio, W J D'Andrea et al.ARTICLEThe Holocene2013Citada por: 1Referencias: 13

    Holocene paleoclimate records from Greenland help us understand the response of the Greenland Ice Sheet and regional oceanic and atmospheric circulation systems to natural climate variability in order to place recent changes in a longer-term perspective. Here biogeochemical analysis of a lake sediment core from southeast Greenland is used to define changes in moisture balance and runoff during the Holocene in a catchment near the margin of the Gr…

  • A multi-proxy approach to assessing isolation basin stratigraphy from the Lofoten Islands, Norway

    Open AccessNicholas L Balascio, Zhaohui Zhang et al.ARTICLEQuaternary Research2011

    This study takes a comprehensive approach to characterizing the isolation sequence of Heimerdalsvatnet, a coastal lake in the Lofoten Islands, northern Norway. We use established methods and explore new techniques to assess changes in marine influence. Bathymetric and sub-bottom profiles were acquired to examine basin-wide sedimentation and a 5.8 m sediment core spanning the last 7800 cal yr BP was analyzed. We measured magnetic susceptibility, b…

  • Multiple Effects of Changes in Arctic Snow Cover

    Open AccessTerry V Callaghan, Margareta Johansson et al.ARTICLEAMBIO2011Citada por: 7Referencias: 76

  • Distal cryptotephra found in a Viking boathouse

    Open AccessNicholas L Balascio, Stephen Wickler et al.ARTICLEJournal of Archaeological Science2010Citada por: 5Referencias: 6

  • Quantitative assessment of precipitation seasonality and summer surface wetness using ombrotrophic sediments from an Arctic Norwegian peatland

    Open AccessJ E Nichols, Marie Walcott et al.ARTICLEQuaternary Research2009

    Seasonality of precipitation is an important yet elusive climate parameter in paleoclimatological reconstructions. This parameter can be inferred qualitatively from pollen and other paleoecological methods, but is difficult to assess quantitatively. Here, we have assessed seasonality of precipitation and summer surface wetness using compound specific hydrogen and carbon isotope ratios of vascular plant leaf waxes and Sphagnum biomarkers extracted…

  • Recent Warming Reverses Long-Term Arctic Cooling

    Open AccessDarrell S Kaufman, David P Schneider et al.ARTICLEScience2009

    Climate Reversal The climate and environment of the Arctic have changed drastically over the short course of modern observation. Kaufman et al. (p. 1236 ) synthesized 2000 years of proxy data from lakes above 60° N latitude with complementary ice core and tree ring records, to create a paleoclimate reconstruction for the Arctic with a 10-year resolution. A gradual cooling trend at the start of the record had reversed by the beginning of the 20th …

  • Global Signatures and Dynamical Origins of the Little Ice Age and Medieval Climate Anomaly

    Open AccessM Mann, Michael E Mann et al.ARTICLEScience2009

    Patterns of Change The global climate record of the past 1500 years shows two long intervals of anomalous temperatures before the obvious anthropogenic warming of the 20th century: the warm Medieval Climate Anomaly between roughly 950 and 1250 A.D. and the Little Ice Age between around 1400 and 1700 A.D. It has become increasingly clear in recent years, however, that climate changes inevitably involve a complex pattern of regional changes, whose …

  • Diatom and stable isotope records of late-Holocene lake ontogeny at Indrepollen, Lofoten, NW Norway

    Open AccessKeely Mills, Anson W Mackay et al.ARTICLEThe Holocene2009Referencias: 13

    Borg Indrepollen is a coastal lake on the island of Vestvågøy, Lofoten, NW Norway. A sedimentary sequence spanning the last 4500 cal. yr BP was analysed for diatom, C/N and stable isotopes (δ 13 C and δ 15 N). The record provides clear evidence of glacio-isostatic rebound in the Lofoten region. Five distinct lithostratigraphic-geochemical zones (I—V) and four major diatom zones (A—D) were identified. The early record (I—III, A—Biii; 4500—550 cal.…

  • The Younger Dryas and the Sea of Ancient Ice

    Open AccessRaymond S Bradley, John H England et al.ARTICLEQuaternary Research2008

    We propose that prior to the Younger Dryas period, the Arctic Ocean supported extremely thick multi-year fast ice overlain by superimposed ice and firn. We re-introduce the historical term paleocrystic ice to describe this. The ice was independent of continental (glacier) ice and formed a massive floating body trapped within the almost closed Arctic Basin, when sea-level was lower during the last glacial maximum. As sea-level rose and the Barents…

  • Proxy-based reconstructions of hemispheric and global surface temperature variations over the past two millennia

    Open AccessM Mann, Michael E Mann et al.ARTICLEProceedings of the National…2008

    Following the suggestions of a recent National Research Council report [NRC (National Research Council) (2006) Surface Temperature Reconstructions for the Last 2,000 Years (Natl Acad Press, Washington, DC).], we reconstruct surface temperature at hemispheric and global scale for much of the last 2,000 years using a greatly expanded set of proxy data for decadal-to-centennial climate changes, recently updated instrumental data, and complementary m…

  • Climate change and tropical Andean glaciers

    Open AccessMarilène Vuille, Mathias Vuille et al.ARTICLEEarth-Science Reviews2008

  • A record of climate over the last millennium based on varved lake sediments from the Canadian High Arctic

    Open AccessMark Besonen, M R Besonen et al.ARTICLEThe Holocene2008Citada por: 1Referencias: 2

    A varved sediment record that extends back over the last millennium was recovered from Lower Murray Lake, northern Ellesmere Island, Nunavut, Canada (81°20′N, 69°30′W). Flatbed scan images and backscattered electron images were analysed to provide varve thickness and other quantitative sedimentary indices on an annual basis. In many studies of lakes from the High Arctic, varve thickness is a good proxy for summer temperature and we interpret the …

  • Yr Pollen Record of Vegetation change in the High Altitude Tropical Andes at Laguna Verde Alta, Venezuela

    Open AccessValentí Rull, Mark B Abbott et al.ARTICLEQuaternary Research2005

    Pollen analysis of sediments from a high-altitude (4215 m), Neotropical (9°N) Andean lake was conducted in order to reconstruct local and regional vegetation dynamics since deglaciation. Although deglaciation commenced ∼15,500 cal yr B.P., the area around the Laguna Verde Alta (LVA) remained a periglacial desert, practically unvegetated, until about 11,000 cal yr B.P. At this time, a lycopod assemblage bearing no modern analog colonized the super…

  • Climate in Medieval Time

    Open AccessRaymond S Bradley, Malcolm K Hughes et al.ARTICLEScience2003

    Many papers have referred to a "Medieval Warm Period." But how well defined is climate in this period, and was it as warm as or warmer than it is today? In their Perspective, Bradley et al. review the evidence and conclude that although the High Medieval (1100 to 1200 A.D.) was warmer than subsequent centuries, it was not warmer than the late 20th century. Moreover, the warmest Medieval temperatures were not synchronous around the globe. Large ch…

  • What Drives Societal Collapse?

    Open AccessH Wei, Harvey Weiss et al.ARTICLEScience2001

    The archeological and historical record is replete with evidence for prehistoric, ancient and pre-modern societal collapse. These collapses occurred quite suddenly and frequently involved regional abandonment, replacement of one subsistence base by another (such as agriculture by pastoralism) or conversion to a lower energy socio-political organization (such as local state from interregional empire). Each of these collapse episodes has been discu…

  • Climate Change – Past, Present and Future

    Raymond S BradleyARTICLEGAIA - Ecological Perspectives…2001

  • Hydrological and meteorological observations at Lake Tuborg, Ellesmere Island, Nunavut, Canada

    C Braun, Douglas R Hardy et al.ARTICLEPolar Geography2000

    Hydrological and meteorological observations at Lake Tuborg, Ellesmere Island, Nunavut, Canada in 1995 are used to investigate contemporary water and sediment transport processes. Here we describe a new environmental data set for the High Arctic, where such data are scarce. The studied watershed (∼460 km2) ranges in elevation between 63 and ∼1900 m asl and is 88% covered by a lobe of the Agassiz Ice Cap. Streamflow and sediment transport were str…

  • Northern hemisphere temperatures during the past millennium

    Open AccessM Mann, Michael E Mann et al.ARTICLEGeophysical Research Letters1999

    Building on recent studies, we attempt hemispheric temperature reconstructions with proxy data networks for the past millennium. We focus not just on the reconstructions, but the uncertainties therein, and important caveats. Though expanded uncertainties prevent decisive conclusions for the period prior to AD 1400, our results suggest that the latter 20th century is anomalous in the context of at least the past millennium. The 1990s was the warme…