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2. Holocene and Last Interglacial cloudiness in eastern Baffin Island, Arctic CanadaThis article is one of a series of papers published in this Special Issue on the themePolar Climate Stability Network.GEOTOP Publication 2008-0027
- Author
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Bianca Fréchette, Pierre J. H. Richard, and Anne de Vernal
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Oceanography ,Arctic ,Interglacial ,General Earth and Planetary Sciences ,Climate change ,Flandrian interglacial ,Vegetation ,Arctic ecology ,Polar climate ,Geology ,Holocene - Abstract
This study presents Last Interglacial and Holocene vegetation and climate changes at Fog Lake (67°11′N, 63°15′W) on eastern Baffin Island, Arctic Canada. The vegetation cover is reported as vegetation structural types (or biomes). July air temperature and sunshine during the growing season (June–July–August–September) were reconstructed from pollen assemblages using the modern analogue technique. The vegetation of the Last Interglacial period evolved from a prostrate dwarf-shrub tundra to a low- and high-shrub tundra vegetation. The succession of four Arctic biomes was distinguished from the Last Interglacial sediments, whereas only one Arctic biome was recorded in the Holocene sediments. From ca. 8300 cal. years BP to present, hemiprostrate dwarf-shrub tundra occupied the soils around Fog Lake. During the Last Interglacial, growing season sunshine was higher than during the Holocene and July air temperature was 4 to 5 °C warmer than present. A principal component analysis helped in assessing relationship between floristic gradients and climate. The major vegetation changes through the Last Interglacial and Holocene were driven by July air temperature variations, whereas the minor, or subtle, vegetation changes seem rather correlated to September sunshine. This study demonstrates that growing season sunshine conditions can be reconstructed from Arctic pollen assemblages, thus providing information on feedbacks associated with cloud cover and summer temperatures, and therefore growing season length.
- Published
- 2008
3. ABSTRACTS OF PAPERS
- Author
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P. Koch, Maria Cristina Salvatore, Carlo Baroni, S. Newsome, and Brenda L. Hall
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Sea coast ,Oceanography ,Geography ,business.industry ,Ecology ,Ecology (disciplines) ,Paleontology ,Distribution (economics) ,Climate change ,business ,Holocene - Published
- 2007
4. Growth rates for freshwater ferromanganese concretions indicate regional climate change in eastern Canada at the Northgrippian-Meghalayan boundary
- Author
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Alex Harrison, Tom A. Al, Jack Cornett, Simon Hayles, and Jiujiang Zhao
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Archeology ,ferromanganese concretions ,010504 meteorology & atmospheric sciences ,Earth science ,Climate change ,010502 geochemistry & geophysics ,01 natural sciences ,Ferromanganese ,Boundary (real estate) ,law.invention ,law ,Radiocarbon dating ,climate ,Holocene ,geochemistry ,0105 earth and related environmental sciences ,Earth-Surface Processes ,Global and Planetary Change ,Ecology ,Paleontology ,15. Life on land ,Research Papers ,6. Clean water ,13. Climate action ,radiocarbon ,Geology - Abstract
The existence of freshwater ferromanganese concretions has been known for decades, but we are not aware of a generally accepted explanation for their formation, and there has been little research into their potential use as records of Holocene climate and paleohydrology. A conceptual model is presented to describe the environmental and geochemical processes which result in the formation and growth of freshwater ferromanganese concretions. In order to evaluate their potential as historical geochemical records, a concretion from Magaguadavic Lake, New Brunswick, Canada is the focus of a detailed geochronological and geochemical investigation. The radiocarbon data provide a coherent growth curve and a maximum age for the concretion of 8448 ± 43 years, consistent with the establishment of Magaguadavic Lake as a stable post-glacial lacustrine system. The data suggest accretion rates of 1.5 and 3.4 mm per 1000 years during the Northgrippian and Meghalayan stages of the Holocene, respectively. The abrupt change in growth rate observed at the stage boundary may be an indicator of Holocene climate change. These features are consistent with inferences from previous research that warmer climate in the Northgrippian led to eutrophication in some lakes in eastern North America. The results confirm that freshwater Fe–Mn concretions may yield important information about past climatic and environmental conditions.
- Published
- 2021
5. Climate change and long-term human behaviour in the Neotropics: an archaeological view from the Global South.
- Author
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Scheinsohn, Vivian, Muñoz, A. Sebastián, and Mondini, Mariana
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HUMAN behavior ,DEVELOPING countries ,CLIMATE change adaptation ,PHYSIOLOGICAL adaptation ,CLIMATE change - Abstract
In this paper, we argue for the inclusion of archaeology in discussions about how humans have contributed to and dealt with climate change, especially in the long term. We suggest Niche Construction Theory as a suitable framework to that end. In order to take into account both human and environmental variability, we also advocate for a situated perspective that includes the Global South as a source of knowledge production, and the Neotropics as a relevant case study to consider. To illustrate this, we review the mid-Holocene Hypsithermal period in the southern Puna and continental Patagonia, both in southern South America, by assessing the challenges posed by this climate period and the archaeological signatures of the time from a Niche Construction Theory perspective. Finally, we emphasize the importance of these considerations for policymaking. This article is part of the theme issue 'Climate change adaptation needs a science of culture'. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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6. Controls on late-Holocene drift-sand dynamics : The dominant role of human pressure in the Netherlands
- Author
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Pierik, H.J., Van Lanen, Rowin, Gouw-Bouman, M.T.I.J., Groenewoudt, Bert, Wallinga, Jakob, Hoek, W.Z., Biogeomorphology of Rivers and Estuaries, Geomorfologie, and Coastal dynamics, Fluvial systems and Global change
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010506 paleontology ,Archeology ,human impact ,010504 meteorology & atmospheric sciences ,Pleistocene ,Climate change ,drift-sand activity ,01 natural sciences ,vegetation development ,Deforestation ,climate ,Mesolithic ,Holocene ,0105 earth and related environmental sciences ,Earth-Surface Processes ,Global and Planetary Change ,Ecology ,Paleontology ,Vegetation ,15. Life on land ,PE&RC ,chronology ,Research Papers ,Bodemgeografie en Landschap ,Geography ,13. Climate action ,Period (geology) ,Soil Geography and Landscape ,Physical geography ,Chronology - Abstract
Holocene drift-sand activity in the northwest European sand belt is commonly directly linked to population pressure (agricultural activity) or to climate change (e.g. storminess). In the Pleistocene sand areas of the Netherlands, small-scale Holocene drift-sand activity began in the Mesolithic, whereas large-scale sand drifting started during the Middle Ages. This last phase not only coincides with the intensification of farming and demographic pressure but also is commonly associated with a colder climate and enhanced storminess. This raises the question to what extent drift-sand activity can be attributed to either human activities or natural forcing factors. In this study, we compare the spatial and temporal patterns of drift-sand occurrence for the four characteristic Pleistocene sand regions in the Netherlands for the period between 1000 BC and AD 1700. To this end, we compiled a new supra-regional overview of drift-sand activity based on age estimates (14C, optically stimulated luminescence (OSL), archaeological and historical ages). The occurrence of sand drifting was then compared in time and space with historical-route networks, relative vegetation openness and climate. Results indicate a constant but low drift-sand activity between 1000 BC and AD 1000, interrupted by a remarkable decrease in activity around the BC/AD transition. It is evident that human pressure on the landscape was most influential on initiating sand drifting: this is supported by more frequent occurrences close to routes and the uninterrupted increase of drift-sand activity from AD 900 onwards, a period of high population density and large-scale deforestation. Once triggered by human activities, this drift-sand development was probably further intensified several centuries later during the cold and stormier ‘Little Ice Age’ (LIA; AD 1570–1850).
- Published
- 2018
7. Accelerating the Renewable Energy Revolution to Get Back to the Holocene.
- Author
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Abbott, Benjamin W., Abrahamian, Chelsea, Newbold, Nicholas, Smith, Peter, Merritt, Marina, Sayedi, Sayedeh Sara, Bekker, Jeremy, Greenhalgh, Mitchell, Gilbert, Sophie, King, Michalea, Lopez, Gabriel, Zimmermann, Nils, and Breyer, Christian
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RENEWABLE energy sources ,ENVIRONMENTAL health ,HOLOCENE Epoch ,RENEWABLE energy costs ,STANDARD of living ,INDUSTRIAL energy consumption ,ENERGY consumption - Abstract
The UN's Paris Agreement goal of keeping global warming between 1.5 and 2°C is dangerously obsolete and needs to be replaced by a commitment to restore Earth's climate. We now know that continued use of fossil fuels associated with 1.5–2°C scenarios would result in hundreds of millions of pollution deaths and likely trigger multiple tipping elements in the Earth system. Unexpected advances in renewable power production and storage have radically expanded our climate response capacity. The cost of renewable technologies has plummeted at least 30‐year faster than projected, and renewables now dominate energy investment and growth. This renewable revolution creates an opportunity and responsibility to raise our climate ambitions. Rather than aiming for climate mitigation—making things less bad—we should commit to climate restoration—a rapid return to Holocene‐like climate conditions where we know humanity and life on Earth can thrive. Based on observed and projected energy system trends, we estimate that the global economy could reach zero emissions by 2040 and potentially return atmospheric CO2 to pre‐industrial levels by 2100–2150. However, this would require an intense and sustained rollout of renewable energy and negative emissions technologies on very large scales. We describe these clean electrification scenarios and outline technical and socioeconomic strategies that would increase the likelihood of restoring a Holocene‐like climate in the next 100 years. We invite researchers, policymakers, regulators, educators, and citizens in all countries to share and promote this positive message of climate restoration for human wellbeing and planetary stability. Plain Language Summary: New research in global ecology and public health shows that the consequences of burning fossil fuels are much more severe than previously understood. Current global warming targets are not enough to protect us from sea level rise, ecosystem collapse, and hundreds of millions of human deaths from fossil fuel pollution. Thankfully, the cost of renewable energy technologies has dropped below the cost of fossil fuels decades faster than predicted. This has triggered a renewable revolution that is transforming the global energy system. Our paper considers the feasibility of accelerating this transition through policy, investment, and strategic research. We conclude that there is a viable pathway to restoring Earth's climate through clean electrification and carbon capture. We call for a global commitment to restore pre‐industrial climate conditions within a century and describe what approaches would increase our chances of success. Accelerating the renewable revolution would move us toward a sustainable civilization by eliminating air pollution, stabilizing climate, reducing energy costs, and enhancing living standards worldwide. Because there is no safe level of climate disruption or pollution death, we believe it is our responsibility to restore a Holocene‐like climate, which we know can support human civilization and other life on Earth. Key Points: Goals of 1.5–2°C are not safe given current understanding of ecosystem climate sensitivity and high social costs of fossil fuel pollutionClimate restoration‐rapidly reestablishing Holocene‐like conditions‐has not been fully considered because of socioeconomic obstaclesStrategic financing and prioritization of clean electrification could create pathways back to the Holocene within a century [ABSTRACT FROM AUTHOR]
- Published
- 2023
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8. The post-fire shift of temperate white pine-birch forest to boreal balsam fir forest in eastern Canada: climate-fire implications.
- Author
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Payette, Serge, Frégeau, Mathieu, Couillard, Pierre-Luc, and Laflamme, Jason
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BALSAM fir ,TAIGAS ,PLANT identification ,WHITE pine ,CLIMATE change - Abstract
Copyright of Botany is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2023
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9. Variations in Spring Atmospheric Circulation on the Southwestern Tibetan Plateau During Holocene Linked to High‐ and Low‐Latitude Forcing.
- Author
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Ma, Qingfeng, Zhu, Liping, Wang, Junbo, Ju, Jianting, and Wang, Yong
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SPRING ,CLIMATE change ,HOLOCENE Epoch ,TIMBERLINE ,POLLEN ,PLANT phenology ,ATMOSPHERIC circulation - Abstract
Recent climate and environment over the Tibetan Plateau (TP) have undergone significant changes, dominated by variations in the Westerlies and the Indian summer monsoon. However, long‐term shifts in atmospheric circulation during the transitional seasons are still lacking. Here we investigate the modern distribution of Tsuga pollen over the central‐western TP and confirm it as an indicator of variable atmospheric circulation in spring. By combining our Tsuga record from Taro Co with existing records in the Tsuga pollen source area, we suggest that a potential particle transport pathway from the southern slope of the Himalayas to the interior of the plateau appeared in the spring of the late Holocene. Our results show that the springtime atmospheric circulation over the southwestern TP during the early and late Holocene is closely related to the substantial remnants of ice sheets at northern high latitudes and the frequency of El Niño events, respectively. Plain Language Summary: The spring climate over the Tibetan Plateau (TP) is undergoing significant changes that yield profound impacts on environmental changes such as variations in vegetation phenology and alpine treeline. Knowledge of long‐term variations in atmospheric circulation during spring can improve the understanding of current climatic and environmental change and the projection of future variability. In this paper, we use an exotic pollen grain, which can be transported long distances in the air, as an indicator to trace the variability of spring atmospheric circulation over the TP. The results indicate that the spring meridional atmospheric circulation from the southern slope of the TP to its interior has been enhanced in the last four thousand years, which is mainly influenced by the frequency of El Niño events. Key Points: Spring atmospheric circulation change over the southwestern Tibetan Plateau (TP) during Holocene is reconstructedMeridional atmospheric circulation in spring over the southwestern TP is strengthened in the late HoloceneHigh‐(low‐) latitude forcing mainly influence the variations in spring atmospheric circulation during the early (late) Holocene [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
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10. RECONSTRUCTING HUMAN−ENVIRONMENTAL RELATIONSHIP IN THE SIBERIAN ARCTIC AND SUB-ARCTIC: A HOLOCENE OVERVIEW.
- Author
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Kuzmin, Yaroslav V
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HOLOCENE Epoch ,CLIMATE change ,TUNDRAS ,WATERSHEDS ,INTERDISCIPLINARY research ,RADIOCARBON dating - Abstract
This paper examines patterns of human–environmental interactions across northern Asia during the Holocene, in order to summarize current knowledge and identify key areas for future research. To achieve these goals, currently available chronological, cultural, and paleoenvironmental datasets from the east Russian Arctic for the last 10,000
14 C years were integrated. Study regions include the Taymyr Peninsula, Lena River basin (except its southern part), northeastern Siberia, and Kamchatka Peninsula. Several broad-scale correlations between climatic fluctuations and cultural responses (e.g., subsistence strategies and occupation densities) were identified; however, these are not straightforward. For example, the increase of occupations during the warm periods in the Early–Middle Holocene are notable while the most pronounced rises coincide with a cooling trend in the Late Holocene. This shows that the human–environmental relationships in the Holocene were not linear; more interdisciplinary research will be needed to construct higher resolution data for understanding prehistoric cultural responses to past environmental changes in the Asian Arctic. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
11. Desertification and Related Climate Change in the Alashan Plateau since the Last 40 ka of the Last Glacial Period.
- Author
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Zhu, Bingqi and Yang, Limin
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DESERTIFICATION ,GLACIATION ,CLIMATE change ,GLOBAL environmental change ,LAST Glacial Maximum ,WIND power - Abstract
Clues of climate change on the Alashan Plateau since the last glacial period (40 ka) are important for revealing the mechanism of desertification of middle-latitude deserts in the Northern Hemisphere (NH). Studies are still rare for the understanding of the specific relationship of climate changes between the Alashan Plateau and the global. Based on a systematic and comparative analysis of the existing research in China and the international academic community, this paper reviews the environmental evolution history of the Alashan Plateau since the last glacial period from the records of paleo-environment and geomorphological characteristics in different deserts of the plateau (e.g., Badanjilin, Tenggeli, and Wulanbuhe). From about 40 ka to the end of the last glacial maximum, the climate on the plateau was wetter than it is today, and to the end of the Pleistocene, the climate was generally dry and the aeolian activities were enhanced. However, the climate was arid during the whole last glacial period in the Wulanbuhe Desert, evidently different from the overall pattern of the plateau. The Tenggeli Desert was characterized by an arid climate in the early Holocene. The most controversial events for the Alashan Plateau are the drought events in the middle Holocene in the Badanjilin Desert. The role and impact of the westerlies and the East Asian Summer Monsoon (EASM) systems on the climate change of the desert and even the whole plateau is a vexed question that brings different views in different periods. There is still a lack of definite evidence representing the events of global environmental change that occurred on the plateau during the discussed period. The distinctive morphology of dune mountains and the distribution of sand dunes are mutually indicative of the direction and energy of wind systems on the plateau. It is suggested that appropriate wind energy is the significant key to the desertification in these middle-latitude deserts on the plateau. From a global-scale review of climate change, the desertification of the modern-scale sandy desert landscapes on the Alashan Plateau is generally related to the global glacial period and the cold and dry climate during the past 40 ka. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
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12. Holocene history of the forest-alpine tundra ecotone in the Scandes Mountains (central Sweden).
- Author
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Kullman, Leif
- Subjects
CLIMATE change ,TREE growth ,FOREST ecology ,DOWNY birch ,SCOTS pine ,ALNUS incana - Abstract
The Holocene history of the forest-alpine tundra ecotone in Central Sweden (Scandes Mountains) is inferred from radiocarbon analyses of subfossil wood remains. Pinus sylvestris was the dominant subalpine tree species during the early Holocene, when it ascended almost 200 m higher than currently. A short climatic episode (less than 100 years) is postulated to have triggered erosional processes around 6300 B.P., and extinguished the upper part of the subalpine pine woodland. Subsequently, a subalpine belt of Betula pubescens ssp. tortuosa and Alnus incana developed. A Holocene thermal optimum occurred around 6100 B.p., when the birch/alder belt flourished and the tree-limits probably reached their highest levels during the Holocene. Shortly after 6000 B.P., a long-term pine forest retrogression started and the birch/alder belt was disrupted by expanding snow-beds. Pine receded slightly at its tree-limit, but the uppermost belt of closed pine forest (presently dominated by birch) remained intact until c. 3300 B.p., when a severe climatic deterioration occurred. The present-day subalpine belt of pure birch forest developed successively and increased in vertical extent after c. 5300 B.P., when summer temperature declined. The evolution of the birch belt is postulated to have been ultimately a response to decreased seasonality, which favoured birch at the expense of pine. Because of the 'inertia' characterizing the highest pine forest, the birch belt was relatively narrow until a major thermal decline c. 3300 B.P., when it made a massive downslope expansion. The latest phase of pine recession was during the Little Ice Age, 800-300B.P. [ABSTRACT FROM AUTHOR]
- Published
- 1988
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13. Response of the Lake Ecosystem of the Lesser Kuril Ridge to Paleoclimatic and Seismic Events.
- Author
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Razzhigaeva, N. G., Grebennikova, T. A., Ganzey, L. A., Ponomarev, V. I., and Kharlamov, A. A.
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LITTLE Ice Age ,YOUNGER Dryas ,FOSSIL diatoms ,CLIMATE change ,EROSION ,LAKES ,BOTANY - Abstract
In this paper we restore moisture changes since the Younger Dryas based on the study of diatom flora in sediments of the Zelenyi coastal paleolake, the Lesser Kuril Ridge. The section includes numerous interlayers of tephra, the sources of which were located on the islands of Kunashir and Hokkaido, and interlayers of tsunamigenic sands, which made it possible to determine the impact of catastrophic events on changes in the ecological situation. The stages of the development of the lake are identified and its evolution is analyzed during short-period climatic rhythms. The reservoir had its maximal depth at the beginning of the Holocene, and planktonic forms predominated among diatoms. Three phases when the lake turned into a lagoon were established, and the erosion of the barrier form most likely caused this during large tsunamis associated with earthquakes. Except for these cases, the main factor leading to the change in lacustrine–marsh environments was climate change. We identified relatively dry periods and wet periods associated with an increase in the intensity of cyclogenesis in the South Kurils region. We correlated with high-resolution paleoclimatic records from archives for the Southern Kuriles; the most striking events were compared with data for Sakhalin and the continent. Changes in moisture on the islands and the margin of the mainland in the Middle–Late Holocene were established to be in antiphase in most cases, except for the cooling of 2800–2500 BP and the Little Ice Age. The connection of regional climatic changes with anomalies in the ocean and atmosphere of the Asia-Pacific region is shown. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
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14. Responses of Caribbean Mangroves to Quaternary Climatic, Eustatic, and Anthropogenic Drivers of Ecological Change: A Review †.
- Author
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Rull, Valentí
- Subjects
MANGROVE plants ,ENDANGERED ecosystems ,SEA level ,LITTLE Ice Age ,FOSSIL hominids ,HOLOCENE Epoch - Abstract
Mangroves are among the world's most threatened ecosystems. Understanding how these ecosystems responded to past natural and anthropogenic drivers of ecological change is essential not only for understanding how extant mangroves have been shaped but also for informing their conservation. This paper reviews the available paleoecological evidence for Pleistocene and Holocene responses of Caribbean mangroves to climatic, eustatic, and anthropogenic drivers. The first records date from the Last Interglacial, when global average temperatures and sea levels were slightly higher than present and mangroves grew in locations and conditions similar to today. During the Last Glaciation, temperatures and sea levels were significantly lower, and Caribbean mangroves grew far from their present locations on presently submerged sites. The current mangrove configuration was progressively attained after Early Holocene warming and sea level rise in the absence of anthropogenic pressure. Human influence began to be important in the Mid-Late Holocene, especially during the Archaic and Ceramic cultural periods, when sea levels were close to their present position and climatic and human drivers were the most influential factors. During the last millennium, the most relevant drivers of ecological change have been the episodic droughts linked to the Little Ice Age and the historical developments of the last centuries. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
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15. John Birks: Pioneer in quantitative palaeoecology.
- Author
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Battarbee, Richard W, Lamb, Henry, Bennett, Keith, Edwards, Mary, Bjune, Anne E, Kaland, Peter E, Berglund, Björn E, Lotter, André F, Seppä, Heikki, Willis, Kathy J, Herzschuh, Ulrike, and Birks, Hilary H
- Subjects
SCIENTISTS ,PALEOECOLOGY ,CLIMATE change ,ECOLOGY ,HOLOCENE paleoecology - Abstract
We describe the career of John Birks as a pioneering scientist who has, over a career spanning five decades, transformed palaeoecology from a largely descriptive to a rigorous quantitative science relevant to contemporary questions in ecology and environmental change. We review his influence on students and colleagues not only at Cambridge and Bergen Universities, his places of primary employment, but also on individuals and research groups in Europe and North America. We also introduce the collection of papers that we have assembled in his honour. The papers are written by his former students and close colleagues and span many of the areas of palaeoecology to which John himself has made major contributions. These include the relationship between ecology and palaeoecology, late-glacial and Holocene palaeoecology, ecological succession, climate change and vegetation history, the role of palaeoecological techniques in reconstructing and understanding the impact of human activity on terrestrial and freshwater ecosystems and numerical analysis of multivariate palaeoecological data. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
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16. Holocene debris flows and snow avalanches in Anestølsdalen, western Norway - recorded from lake deposits and colluvial fans.
- Author
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Aa, Asbjørn Rune, Bondevik, Stein, and Sønstegaard, Eivind
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HOLOCENE extinction ,LAKE sediments ,CLIMATE change ,GLACIERS ,SLOPES (Physical geography) - Abstract
Climate variability has probably affected the frequency and distribution of debris flows and snow avalanches throughout the Holocene. In this paper, we reconstruct the Holocene history of debris flows and snow avalanches by investigating outcrops in colluvial fans surrounding lake Anestølsvatnet in western Norway and sediment cores penetrating the lake-floor deposits. We made a detailed map of the surface deposits around the lake. The formation of a large end moraine that dams the lake was radiocarbon dated to 10,200-10,800 cal. yr BP, and correlates to the Erdalen event, a Preboreal glacial oscillation. There are colluvial fans and debris-flow paths and snow-avalanche paths eroded on the steep slopes around the lake. On the western slopes, the fans are dominated by snow avalanches, and on the eastern slopes by debris-flow activity. Three of the lake cores were taken distal to the largest avalanche fan on the western slope, Storeskreda ('Storeskreda' means 'the big landslide'). Clasts > 2 mm in the lake sediments are interpreted as traces of snow avalanches and sorted sand layers as being derived from debris flows. Loss-on-ignition and magnetic susceptibility measurements document an increased silt content in the lake sediments after c. 6000 cal. yr BP, probably due to the reappearance of local glaciers in the area. Our combined data from the onshore outcrops/pits and lake sediments shows almost continuous snowavalanche activity and debris-flow activity throughout the last 10,000 years. However, there may have been an increase in the snow-avalanche activity over the last 5000 years. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
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17. History of slope instability in the Oldina plantation, Tasmania.
- Author
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Slee, Adrian and McIntosh, Peter D.
- Subjects
LANDSLIDES ,CLIMATE change ,RAINFALL ,PINUS radiata ,RADIOCARBON dating ,HOLOCENE Epoch - Abstract
Background: This paper describes a landslide swarm generated by exceptionally high two-day rainfall (c. 300 mm) associated with a stationary cut-off low pressure system over northern Tasmania in early June 2016 and investigates evidence for previous slope instability. The landslide swarm occurred in a recently harvested plantation in the Inglis River catchment at Oldina, south of Wynyard in north-west Tasmania. Within a relatively small area of plantation underlain by weathered Permian tillite and minor siltstones more than thirty rapid earthflows, rotational and translational landslides occurred. Many landslides also occurred in the nearby Forth and Mersey River catchments. Methods: Field observations combined with a digital elevation model produced from high-resolution drone imagery were used to describe the morphology of the Oldina landslides, and to calculate the mass of soil, sediment, and woody debris displaced. Radiocarbon dating of charcoal exposed in landslide backwalls enabled palaeo-landslides and periglacial activity at Oldina to be dated. Results: An estimated 48,400-72,310 t of soil, sediment and woody debris was carried downslope by the major landslides but has been retained within the plantation area. The total sediment loss from the affected upper catchments is likely to be greater than the above estimate as the contribution from small riparian landslides, sheet, gully, and rill erosion has not been accounted for, nor has streambank erosion and sediment transported off the study site been measured. Radiocarbon dating of charcoal in sediments indicated that two landslides had evidence of previous instability in the Holocene. Most ages indicated that previous instability dated to 35-15 cal ka BP, i.e., to a time when the climate was cold and dry and freeze-thaw processes in a sparsely vegetated landscape were active. Conclusions: During planning for harvest the soils developed on Permian tillite were correctly described as having a low to moderate risk of landslide erosion. This study concludes that the landslides initiated in June 2016 resulted from exceptionally heavy rain falling on harvested steep and hilly land coupled with the decline in root strength of the harvested trees. The frequency of such a combination of circumstances may increase if high-intensity rainfall increases in Tasmania as the result of climate change. To improve the long-term stability of this terrain and the overall sustainability of plantation forestry it is recommended that landslides and riparian areas are seeded with native vegetation, and that the current assessment of landslide risk for this terrain is re-evaluated. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
18. Peatland history under post-glacial climate changes in the southern Baikal region: Biogeochemical evidence from the Vydrino Bog (Tankhoi piedmont plain).
- Author
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Bobrov, Vladislav A., Maltsev, Anton E., Krivonogov, Sergey K., Preis, Yulia I., Klimin, Mikhail A., and Leonova, Galina A.
- Subjects
- *
BOGS , *GLOBAL warming , *ENVIRONMENTAL quality , *PEATLANDS , *PLAINS , *VEGETATION dynamics , *CLIMATE change , *FIR - Abstract
The paper presents new data and reviews previously obtained results on the late glacial to Holocene history of peatlands in the southern part of the Baikal region under conditions of regional climate changes. To better understand climate signals, we have combined vegetation and geochemical variation data in 4.6 m thick peat deposits in the Vydrino bog located on the Tankhoi piedmont plain south of Lake Baikal. The territory has been swamped since 13.1 cal ka BP when the peatland started developing as a fen upon a sedimentary substrate. The 13.1–9.5 cal kyr climate record included two events of warming separated by an excursion of dry cold climate. Warming continued till 9.0 cal ka BP and eutrophic peat formation occurred in favorable temperature and moisture conditions. Another warming episode between 9.0 and 8.4 cal ka BP ended up with the Holocene climate optimum while the bog became mesotrophic. About 7.3–6.5 cal ka BP, the temperature and moisture inputs were no longer optimal for fir and spruce forests in the Vydrino area, which led to dramatic changes in landscape and vegetation. The wet and warm climate gradually became drier and colder from 6.5 to 2.3 cal ka BP, with a brief warm excursion about 5.5–5.3 cal ka BP. The peat deposition was interrupted in a cold climate from ∼2.3 cal ka BP to ∼0.7 cal ka BP, and the bog became oligotrophic afterwards. The newly obtained data allowed us to compare the paleoclimatic indicators available for the south Baikal region to determine their compatibility and inconsistency. In addition, we provide a general view to the quality of the climate and environmental reconstructions in the Baikal region by comparison of the data on its peatland study. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
19. BIOTIC CRISES RELATED TO THE PALEOCLIMATE DETERIORATION.
- Author
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Melinte-Dobrinescu, Mihaela, Ion, Gabriel, Briceag, Andrei, Anton, Eliza, and Apotrosoaei, Vlad
- Subjects
OCEAN acidification ,PALEOCLIMATOLOGY ,CLIMATE change ,ICE caps ,SEAWATER ,METEORITES ,OLIGOCENE Epoch - Abstract
Our planet experienced many intervals of climate deterioration due to terrestrial causes, such as intensified volcanism and a very active tectonic regime or extraterrestrial causes. The later includes major meteorite impacts and change in the exosphere, mostly linked to the modification of sunlight amount leading to glaciations. The most sensitive organisms to climate changes are the marine planktonic ones, especially the coccoliths and dinoflagellates. This paper describes modification in the marine planktonic world during three specific intervals: (1) K/T boundary, when the meteorite impact led to the acidification of ocean surface waters and the disappearance of over 80 % of marine planktonic taxa; (2) Oligocene cooling and instauration of permanent North Pole ice cap, along with the separation of the Tethys Ocean in the Mediterranean and Paratethyan Sea; the later occupied large areas in the Central and Eastern Europe; (3) The reconnection of the Black Sea with Mediterranean during Holocene times. These events are accompanied by shift of calcareous nannoplankton assemblages, including blooms of Braarudosphaera bigelowii, along with calcareous dinoflagellate taxa of Thoracosphaera. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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20. Influence of Agulhas forcing of Holocene climate change in South Africa's southern Cape.
- Author
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Chase, Brian M. and Quick, Lynne J.
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HOLOCENE Epoch ,CLIMATE change ,LITTORAL zone ,AGULHAS Current - Abstract
This paper analyses a series of high-quality continuous records from southeastern Africa to study the spatiotemporal patterning of Holocene hydroclimatic anomalies in the region. Results indicate dominant frequencies of variability at millennial time scales, and a series of anomalies broadly common to all records. Of particular interest, data from the southern Cape coast exhibit periods of wetter/drier conditions that are out of phase with the sites less than 150 km away in the adjacent interior, but in phase with sites in tropical regions over 1000 km to the northeast. To explain such spatial patterns and gradients, we propose that the Agulhas Current may be a critical vector by which tropical climatic signals are propagated along the littoral zone, exerting a dominant, highly localized influence on near-coastal environmental conditions. Limitations in the data available do not allow for a detailed examination of the climatic dynamics related to these phenomena, but this paper highlights a series of avenues for future research to clarify the spatial extent and stability of the patterns observed. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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21. Investigating possible links between Holocene environmental changes and cultural transitions across India.
- Author
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Behera, Diptimayee and Chauhan, Parth R
- Subjects
- *
HOLOCENE Epoch , *SOCIAL change , *CLIMATE change , *MATERIAL culture , *AGRICULTURE , *CLIMATIC zones - Abstract
From the early Holocene onward, the Indian Subcontinent has accommodated a range of diverse human cultures and associated ecological adaptations and lifestyles. Around 10 kyrs ago, the Subcontinent has witnessed the development of later Mesolithic hunter-gatherers and their subsequent regional transitions to pastoralist (Neolithic) and agricultural (Chalcolithic) lifeways. The Holocene climate records reveal discrepancies in the timing and duration of climatic events, which can be attributed to a vast geographic isolation, the influence of height, elevation, and local climatic conditions. These changing climatic patterns including the development of a geographically variable monsoon directly impacted these various cultures including the Harappans and their contemporaries as well as younger Historical and Medieval empires across India, at various levels. In some regions, environmental changes led to uneven cultural transitions, geographic migrations, and the development of regionally-distinct material cultures along with establishment of sedentary life-ways. This paper attempts to present a review broadly correlating general climatic patterns throughout the Holocene period of India with regional cultural dynamics. All geomorphic-climatic zones of the Subcontinent showed strong inter-proxy coherence between 9 and 5 kyrs in response to increased precipitation. After this warming period ends, we see a moderate dry period as a result of a weakening monsoon and an overall tendency toward aridity throughout all zones (after 4 kyrs). The temporal variation of human habitation and respective adaptive responses suggest broad linkages to the varying climatic and physiographic features at a regional scale. Learning how this shaped human eco-dynamics in the past can help us expand our understanding of human history and implement lessons for the present as well as the future. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
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22. Paleoenvironmental Reconstruction from Palaeolake Sediments in the Area of Ouargla (Northern Sahara of Algeria).
- Author
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Youcef, Fouzia and Hamdi-Aïssa, Baelhadj
- Subjects
PALEOENVIRONMENTAL studies ,LAKE sediments ,QUATERNARY paleoclimatology ,CLIMATE change ,HUMIDITY ,CALCAREOUS soils ,SOIL crusting - Abstract
The hyper-arid climate of Ouargla area (Northern Sahara of Algeria) is important in the field of the paleoenvironmental reconstitution. This paper investigates the importance of palaeolake sediments as significant terrestrial archives for studying Quaternary climate changes. Through morphological and mainly micromorphological investigations of the studied sites (Sabkha of Ouargla and palaeolake of Mellala), we noted the fluctuation of climate between arid and more humid conditions during Quaternary. Some pedofeatures have recorded these environmental changes. The studied calcareous crusting has a lacustrine origin when precipitations were more important. The clay coatings around the quartz grains indicate an old origin and different geochemical conditions that led to their dissolution. Lenticular gypsum crystals were formed from groundwater saturated with Ca2+andions. Calcite pseudomorphs after lenticular gypsum crystals indicate changes in local climatic parameters. Gypsum crusts can be explained by formation under wet climatic conditions in a lagoonal environment. Black and gray layers indicate evolution of organic matter at a wetter period. This paper highlights an unknown palaeolake which can be useful for the comprehension of the ecological past of the Sahara. The comparison between this palaeolake and other Saharan palaeolakes has allowed us to assign it to a probable active period between 10000 and 4000 years B.P. [ABSTRACT FROM PUBLISHER]
- Published
- 2014
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23. Winter temperature and forest cover have shaped red deer distribution in Europe and the Ural Mountains since the Late Pleistocene.
- Author
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Niedziałkowska, Magdalena, Doan, Karolina, Górny, Marcin, Sykut, Maciej, Stefaniak, Krzysztof, Piotrowska, Natalia, Jędrzejewska, Bogumiła, Ridush, Bogdan, Pawełczyk, Sławomira, Mackiewicz, Paweł, Schmölcke, Ulrich, Kosintsev, Pavel, Makowiecki, Daniel, Charniauski, Maxim, Krasnodębski, Dariusz, Rannamäe, Eve, Saarma, Urmas, Arakelyan, Marine, Manaseryan, Ninna, and Titov, Vadim V.
- Subjects
RED deer ,LAST Glacial Maximum ,CLIMATE change ,CLIMATIC zones ,TEMPERATE forests - Abstract
Aim: The Expansion‐Contraction model has been used to explain the responses of species to climatic changes. During periods of unfavourable climatic conditions, species retreat to refugia from where they may later expand. This paper focuses on the palaeoecology of red deer over the past 54 ka across Europe and the Urals, to reveal patterns of change in their range and explore the role of environmental conditions in determining their distribution. Location: Europe and western Asia to 63°E. Taxon: Red deer (Cervus elaphus). Methods: We collected 984 records of radiocarbon‐dated red deer subfossils from the Late Pleistocene and the Holocene, including 93 original dates. For each deer sample we compiled climatic and biome type data for the corresponding time intervals. Results: During the last 54 ka changes in red deer range in Europe and the Urals were asynchronous and differed between western and eastern Europe and western Asia due to different environmental conditions in those regions. The range of suitable areas for deer during the Last Glacial Maximum (LGM) was larger than previously thought and covered vast regions not only in southern but also in western and eastern Europe. Throughout the period investigated the majority of specimens inhabited forests in the temperate climatic zone. The contribution of forests in deer localities significantly decreased during the last 4 ka, due to deforestation of Europe caused by humans. Mean January temperature was the main limiting factor for species distribution. Over 90% of the samples were found in areas where mean January temperature was above −10°C. Main conclusions: Red deer response to climatic oscillations are in agreement with the Expansion‐Contraction model but in contradiction to the statement of only the southernmost LGM refugia of the species. During the last 54 ka red deer occurred mostly in forests of the temperate climatic zone. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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24. The Development of the Natural Environment in the Valley of the Knevichanka River in the Middle and Late Holocene (Southern Sikhote-Alin).
- Author
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Belyanin, P. S., Belyanina, N. I., and Grebennikova, T. A.
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HOLOCENE Epoch ,STRAITS ,CLIMATE change ,ALLUVIAL plains ,MIXED forests ,HUNTER-gatherer societies - Abstract
This paper presents a reconstruction of the history of development of the ecosystems in the lower reaches of the Knevichanka River over the past 5350 cal BP based on the biostratigraphic analysis of the sediments of the first terrace above the floodplain. Differences were identified and characteristics were determined in the vegetation structure during the final phase of the Holocene climate optimum and multidirectional climatic fluctuations in the Late Holocene. It has been found that in the final phase of the Holocene broad-leaved plants were more widespread on the mountain slopes than at present. The alluvial plains predominantly contained grassy meadows with small-leaved plant communities. Mixed forests prevailed in the vegetation on the slopes of the Knevichanka River valley with a dominance of Korean pine, Japanese red pine, oak, elm, Amur cork tree, linden, lilac, Manchurian walnut, and other species. In the lower reaches of the Knevichanka River, in the place of the marshy plains and water areas of Lakes Krolevetskoe and Orlovskoe, an extensive shallow sea bay existed, which was connected to the Ussuri Bay via a narrow strait. A cooling period that began at the end of the Middle Holocene and continued into the beginning of the Late Holocene led to a reduction of broad-leaved plants in vegetation and more widespread occurrence of small-leaved plants. At that time, the formation of the soil layer of the first terrace above floodplain began in the lower reaches of the river. In the course of the marine regression, the coastal lowlands became free from seawater, and the upper part of the shallow bay was detached from the sea. A lagoon occurred at the location of the marine gulf. The lagoon became gradually freshened, shallow, and connected to the sea by the channels of the Knevichanka and Artemovka rivers. However, during the syzygial tides and wind-induced surges, seawater still intruded regularly. At the end of the Late Holocene, the valley of the Knevichanka River developed natural conditions, thus giving rise to the recent structure of vegetation. Desalination occurred in lakes Krolevetskoe and Orlovskoe, while they acquired their recent outlines. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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25. Introduction to the JoPL special issue, 'Holocene paleoenvironmental records from Arctic lake sediment'.
- Author
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Kaufman, Darrell
- Subjects
HOLOCENE Epoch ,CLIMATE change ,LAKES ,SEDIMENTS ,GEOLOGICAL time scales - Abstract
The 18 papers in this Special Issue of the Journal of Paleolimnology report new records of Holocene environmental and climate change from Arctic lake sediment. At least 15 distinct physical, chemical, and biological properties were analyzed at lakes located across the North American Arctic and subarctic, and northwestern Europe. The studies are notable for their multi-proxy approach (eight present data for at least five different proxies), and for the high quality of their geochronological control. Three of the studies analyzed sediment from more than one lake to test the influence of contrasting physiographic settings on the response of proxies to the same climate forcing. The sedimentary sequences analyzed in seven studies extend beyond 11.5 cal ka, providing evidence for pronounced climate shifts that took place during the late-glacial period. Two-thirds extend beyond 8 cal ka; many of these records were interpreted in terms of the shift in temperature and moisture that occurred during the transition from the warm early to middle Holocene to the cooler late Holocene. These records contribute to the growing network of sites that is needed to reconstruct the spatial pattern of this pronounced paleoclimate transition, and to address how ocean-atmospheric circulation changed with the mean state of climate. [ABSTRACT FROM AUTHOR]
- Published
- 2012
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26. Lama guanicoe bone collagen stable isotope (C and N) indicate climatic and ecological variation during Holocene in Northwest Patagonia.
- Author
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Gil, Adolfo F., Otaola, Clara, Neme, Gustavo A., Peralta, Eva A., Abbona, Cinthia, Quiroga, Gisela, Dauverné, Armando, and Seitz, Viviana P.
- Subjects
- *
STABLE isotopes , *HOLOCENE Epoch , *BONES , *CLIMATE change , *COLLAGEN - Abstract
This paper explores how significant are the ecological and climatic variables to influence the stable isotopes of guanacos. Lama guanicoe bone collagen carbon and nitrogen stable isotope ratios are assumed as a macro regional average value in west Argentina, mostly as a baseline to model archaeological human diet. If stable isotopes on mammals reflex ecology and climate, we need to know how those variables influence mammals bone stable isotope ratio. This paper analyses the 13C/12C and 15 N/14N ratio on bone collagen on 122 guanacos from Northwest Patagonia during the Holocene. The results confirm significant variation in both isotopes between Monte and Andean-Patagonian specimens. Guanacos from Monte shows higher δ13C and δ15N than those from Andean-Patagonian. Temporal trends indicate variation through Holocene but this variation is not spatially homogeneous. In this paper we suggest that Medieval Climatic Anomaly had stronger effect in Monte desert than in Patagonia desert, generating driest and/or hottest conditions between 1250 and 600 years BP. Those variations need to be considered to reconstruct human diet at least during the second part of the Holocene. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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27. Drought Cycles Over the Last 8,200 Years Recorded in Maar Lake Twintaung, Myanmar.
- Author
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Chu, Guoqiang, Zhu, Qingzeng, Sun, Qing, Su, Youliang, Xie, Manman, Zaw, Than, and Sein, Kyaing
- Subjects
DROUGHTS ,CARBON isotopes ,VOLCANIC eruptions ,VOLCANISM ,CLIMATE change - Abstract
The tropical Asian regions are particularly prone to catastrophic droughts due to high temperature and evaporation and their sensitivity to variable oceanic‐atmospheric circulation. The extent to which future global warming may intensify droughts in this populous region is a matter of utmost concern. Palaeoclimatic data can help inform scientists learn more about the temporal patterns and drivers of monsoon change over geological timescales. In this paper, we present a new 8,200 year biomarker record preserved in the annually laminated sediments of Maar Lake Twintaung, Myanmar. The δ13C27‐35 sedimentary record is mainly derived from leaf wax lipids in the lake catchment, which is presently dominated by C3 vegetation in the modern lake catchment. The δ13C27‐35 is mainly regulated by plant physiological and biochemical responses to drought stress and, as such, can be used as a proxy of past changes in moisture. The δ13C27–35 record reveals distinct decadal‐to‐centennial‐scale droughts superimposed on a trend of gradually decreasing summer monsoon intensity from the mid‐Holocene to late Holocene. Within the limits of the dating uncertainties, these decadal‐to‐centennial‐scale droughts are found to be well correlated with the southward shift of the Intertropical Convergence Zone. It highlights thepimportance of the Intertropical Convergence Zone shift (tropical monsoon trough) in regulating monsoon rainfall in the region. In addition, most of the droughts are likely to be linked with active volcanism and solar minima and suggest a coupled process between external drivers and internal climate dynamics. Key Points: Leaf wax n‐alkanes record in varved sediment of Maar lake Twintaung, MyanmarThe result indicates distinct decadal‐to‐centennial‐scale droughts over the past 8.2 kaThe drought cycles link with the ITCZ shift, solar and volcanic eruption [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
28. The 'Anthropocene' is most useful as an informal concept.
- Author
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Swindles, Graeme T., Roland, Thomas P., and Ruffell, Alastair
- Subjects
ANTHROPOCENE Epoch ,PHILOSOPHY of science ,SCIENCE in literature ,SCIENTIFIC literature ,EARTH (Planet) ,CLIMATE change - Abstract
Anthropocene, geology, Holocene, human impact, stratigraphy The "Anthropocene" is most useful as an informal concept Keywords: Anthropocene; geology; Holocene; human impact; stratigraphy EN Anthropocene geology Holocene human impact stratigraphy 453 454 2 05/09/23 20230501 NES 230501 The "Anthropocene" (Crutzen & Stoermer, [4]; Crutzen, [3]) concept has rapidly gained prominence in recent years in both public narratives around the climate and environmental crisis, and academic discourses across a range of disciplines - the latter being demonstrated by the multitude of papers published discussing various aspects of the proposed new geological epoch (e.g. Waters et al., [14]). [Extracted from the article]
- Published
- 2023
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29. Ötzi, 30 years on: A reappraisal of the depositional and post-depositional history of the find.
- Author
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Pilø, Lars, Reitmaier, Thomas, Fischer, Andrea, Barrett, James H, and Nesje, Atle
- Subjects
- *
ICE fields , *ARCHAEOLOGICAL excavations , *BEDROCK , *MASS budget (Geophysics) , *GLACIERS , *RADIOCARBON dating , *GLACIOLOGY , *COMMUNITIES , *ALPINE glaciers - Abstract
When Ötzi, the Iceman, was found in a gully in the Tisenjoch pass in the Tyrolean Alps in 1991, he was a huge surprise for the archaeological community. The lead initial investigator of the find argued that it was unique, preserved by serendipitous circumstances. It was hypothesised that the mummy with associated artefacts had been quickly covered by glacier ice and stayed buried until the melt-out in 1991. It is now more than 30 years since Ötzi appeared. In this paper, we take a closer look at how the find can be understood today, benefitting from increased knowledge gained from more than two decades of investigations of other glacial archaeological sites, and from previous palaeo-biological investigations of the find assemblage. In the light of radiocarbon dates from the gully and new glaciological evidence regarding mass balance, it is likely that Ötzi was not permanently buried in ice immediately after his death, but that the gully where he lay was repeatedly exposed over the next 1500 years. We discuss the nature of the ice covering the site, which is commonly described as a basally sliding glacier. Based on the available evidence, this ice is better understood as a non-moving, stationary field of snow and ice, frozen to the bedrock. The damaged artefacts found with Ötzi were probably broken by typical postdepositional processes on glacial archaeological sites, and not, as previously claimed, during conflict prior to Ötzi's flight from the valley below. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
30. Pollen-based seasonal temperature reconstruction in Northeast China over the past 10,000 years, and its implications for understanding the Holocene Temperature Conundrum.
- Author
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Geng, Rongwei, Zhao, Yan, Herzschuh, Ulrike, Cui, Qiaoyu, Zheng, Zhuo, Xiao, Xiayun, Ma, Chunmei, and Liang, Chen
- Subjects
- *
PARTIAL least squares regression , *FOSSIL pollen , *COLD (Temperature) , *ATMOSPHERIC models , *CLIMATE change - Abstract
The Holocene Temperature Conundrum refers to the mismatch between proxy-based temperature records and those based on climate model simulations. A possible reason for this mismatch is a putative proxy-based bias in reconstructed summer temperatures, and therefore, regional reconstructions of seasonal temperature are crucial for resolving the conundrum. In this paper, we reconstruct vegetation and climate changes over the last ∼10,000 years BP based on a high-resolution pollen record from Gushantun peatland, Changbai Mountains, Northeast China. Multiple quantitative reconstruction approaches were used and weighted averaging partial least squares regression (WAPLS) was found to be the most appropriate method for reconstructing Holocene temperature and precipitation. The reconstructed climate record shows that the Holocene Climate Optimum occurred between 8 ka and 6 ka and exhibited a cold month mean temperature that was 3 °C warmer than modern temperatures. Climate gradually cooled during late Holocene with a minimum cold month temperature of −19.6 °C. Four prominent cold events occurred around 8.7 ka BP, 7.8 ka BP, 5.7 ka BP, and 2.5 ka BP with an amplitude variation up to 3 °C. The synthesized seasonal temperature time series and a comparison with other proxies show that the decreasing trend in mean annual temperature is not a seasonal bias caused by summer temperature change. This study provides evidence of a Holocene seasonal temperature change at a regional scale and insights for further understanding of the Holocene Temperature Conundrum. • Reconstructed seasonal temperature changes based on a new high-resolution fossil pollen record in the Changbai Mountains • Synthesized climatic series in Northeast China to investigate the characteristics of regional temperature changes and their driving factors • Reconstructed winter temperature as evidence to address the alleged seasonal bias for the Holocene temperature conundrum [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
31. The limited link between accommodation space, sediment thickness, and inner platform facies distribution (Holocene–Pleistocene, Bahamas).
- Author
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Weij, Rieneke, Reijmer, John J. G., Eberli, Gregor P., and Swart, Peter K.
- Subjects
TIDAL currents ,WATER depth ,SEDIMENTS ,SEAWATER ,CLIMATE change ,MILANKOVITCH cycles - Abstract
Cyclic facies variations in shallow‐water carbonate platforms often show repetitive facies patterns that are frequently interpreted to reflect the sedimentary response to variations in sea‐level related to changes in climate linked to orbital variations, the Milankovitch frequencies. Whether these shallow‐marine carbonates represent a complete infill of accommodation space, or are subtidal cycles, has been discussed in numerous papers. The extent to which the thickness of a single depositional cycle is a direct measure of the amplitude of relative sea‐level change is not fully understood. New shallow seismic data from Great Bahama Bank reveal that accommodation space created during the Holocene sea‐level rise is not filled in a predictable way. Three seismic horizons were identified: the seabed, the Pleistocene top, and a horizon within the Pleistocene. Depth surface and thickness maps of the Holocene and Pleistocene layers were combined with 326 in situ water‐depth measurements to assess the upper limit of the present accommodation space. The analysis showed that accommodation space and Holocene sediment thickness, and water depth are not correlated. In addition, the actual water depth and inner platform facies distribution showed no straightforward link. The energy distribution across the shallow‐water platform appears to control the facies type rather than water depth. Mud‐dominated sediments prevail in shallow low‐energy areas protected by a topographic barrier, whereas mud‐free coarse‐grained sediments mainly occur in deeper areas with hydrodynamic energy induced by strong tidal currents, ocean water influx, and winds. Hence, the uneven energy distribution not only results in unpredictable differences in the carbonate‐cycle thickness on the platform but also to a water depth independent facies distribution pattern within the inner platform. Therefore, care should be taken when deducing sea‐level signals from inner platform facies distribution and sediment thickness patterns on ancient platforms. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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32. The Dynamics of Mediterranean Africa, ca. 9600-1000 bc: An Interpretative Synthesis of Knowns and Unknowns.
- Author
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Broodbank, Cyprian and Lucarini, Giulio
- Subjects
PASTORAL societies ,INFORMATION society ,TRADITIONAL knowledge ,IRON Age ,EMERGENCE (Philosophy) ,INDIGENOUS peoples ,INDIGENOUS Australians - Abstract
Mediterranean Africa forms a crucial junction between the wider Saharan zone and the rest of the Mediterranean. In contrast to its well-investigated history from the first millennium BC onward, its antecedent dynamics are very poorly understood, and deeper archaeological histories of the Mediterranean therefore remain unbalanced and incomplete. This paper draws on a new surge in data to present the first up-todate interpretative synthesis of this region's archaeology from the start of the Holocene until the threshold of the Iron Age (9600-1000 bc). It presents the evidence for climatic, environmental and sea-level change, followed by analysis of the chronological and spatial patterning of all radiocarbon dates from Mediterranean Africa, brought together for the first time. The principal exploration then divides into three phases. During Phase 1 (9600-6200 bc) diverse forms of hunting, gathering and foraging were ubiquitous. Phase 2 (6200-4000 bc) witnessed more continuity than elsewhere in the Mediterranean, but also the widespread uptake of domesticated livestock and gradual evolution of herding societies, as well as limited enclaves of farming. Phase 3 (4000-1000 bc) has been least explored, outside developments in Egypt; in the east this phase witnessed the emergence of fully nomadic and transhumant pastoralism, with political superstructures, while trajectories in the west remain obscure, but in parts of the Maghreb suggest complex possibilities. Contacts with the Mediterranean maritime world grew during the third and second millennia bc, while interaction to the south was transformed by desertification. Understanding how the southern Mediterranean shore was drawn into Iron Age networks will require much better knowledge of its indigenous societies. The present constitutes a pivotal moment, in terms of accumulated knowledge, pathways for future investigation and engagement with a challenging current geopolitical situation. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
33. A high‐resolution record of Holocene climate and vegetation dynamics from the southern Cape coast of South Africa: pollen and microcharcoal evidence from Eilandvlei.
- Author
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Quick, Lynne J., Chase, Brian M., Wündsch, Michael, Kirsten, Kelly L., Chevalier, Manuel, Mäusbacher, Roland, Meadows, Michael E., and Haberzettl, Torsten
- Subjects
HOLOCENE extinction ,VEGETATION dynamics ,POLLEN ,CHARCOAL ,CLIMATE change - Abstract
ABSTRACT: The southern Cape is a particularly dynamic region of South Africa in terms of climate change as it is influenced by both temperate and tropical circulation systems. This paper presents pollen and microcharcoal data generated from a sediment core extracted from the coastal lake Eilandvlei spanning the last ∼8900 years. With an average sample resolution of 57 years, this record represents the highest resolution record of Holocene vegetation change from the region. The data indicate that cool, seasonal and moderately dry conditions characterized the Wilderness Embayment from ∼8900 to 8000 cal a BP. Afrotemperate forests expanded from ∼8000 cal a BP until 4700 cal a BP. This humid period is followed by indications of more arid and seasonal conditions until 3500 cal a BP. A long‐term increase in forest taxa suggests steadily increasing moisture availability across the late Holocene. Strong affinities are noted with records from more tropical regions of South Africa, suggesting that tropical systems are of importance in maintaining higher moisture availability in the region. An important mechanism of climate change is the Agulhas Current, which transmits what appears to be a localized signal of tropical variability to the southern Cape coast. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
34. Length of astronomical seasons, total and average insolation over seasons.
- Author
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Berger, André, Yin, Qiuzhen, and Wu, Zhipeng
- Subjects
- *
SOLAR radiation , *EARTH'S orbit , *SEASONS , *CLIMATE change , *MILANKOVITCH cycles , *HOLOCENE Epoch , *LATITUDE - Abstract
Daily insolation at a given latitude is often used in the explanation of the long-term variations of paleoclimate records. However, the length of astronomical seasons, which has been paid less attention, could also be important. This paper provides an original calculation of the length of these seasons using the eccentric anomaly. The past and future long-term variations as well as the spectral characteristics of the length of astronomical seasons, of the total and average insolation over the astronomical seasons and of the caloric insolation are shown and compared. The length of astronomical seasons is only a function of climatic precession. The total irradiation for a given latitude and an astronomical season is mainly a function of obliquity except that it is mainly a function of eccentricity in a latitudinal band that is season dependent and from where the phase between obliquity and total irradiation reverses (e.g. ∼11.5°N for the astronomical northern hemisphere summer half-year). The spectral characteristic of the mean insolation over the astronomical summer half-year varies in latitude and time. It contains stronger obliquity signal in high latitudes than in low latitudes, but the obliquity signal already gets very weak at 45°N/S leaving the dominance of climatic precession between 45°N and 45°S. The variation of the mean summer half-year insolation over the last 1 Ma is characterized by a Mid-Brunhes transition at ∼450 ka BP, with a dominant role of climatic precession at all latitudes before ∼450 ka BP but significantly enhanced role of obliquity in high latitudes after this time. The simultaneous weakening of the variations of climatic precession and obliquity around 800 ka ago, a time corresponding to the Mid-Pleistocene Transition, leads to weak variations in both total and mean seasonal insolation. The insolation of a specific case, the Holocene, is finally discussed. Depending on the sensitivity to different types of insolation, different climate variables and regions could show different evolution and trend during the Holocene. • An original calculation of the length of the astronomical seasons is provided. • Precession and obliquity contribute differently to the length of astronomical seasons and to different insolation metrics. • Distinctive variations of total and mean seasonal insolation characterize the Mid-Brunhes and Mid-Pleistocene transitions. • Different insolation metrics display different trend over the Holocene. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
35. Holocene Paleoclimate Changes around Qinghai Lake in the Northeastern Qinghai-Tibet Plateau: Insights from Isotope Geochemistry of Aeolian Sediment.
- Author
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Peng, Qiang, E, Chongyi, Li, Xiangzhong, Sun, Yongjuan, Zhang, Jing, Zhang, Shuaiqi, Shi, Yunkun, Ji, Xianba, and Zhang, Zhaokang
- Subjects
CLIMATE change ,LAKE sediments ,ATMOSPHERIC temperature ,FREQUENCIES of oscillating systems ,ISOTOPE geology - Abstract
The stable carbon isotope composition of total organic matter (δ
13 Corg ) has been utilized in aeolian sediments, serving as an indicator for reconstructing terrestrial paleoenvironments. The Qinghai Lake (QHL) Basin is a climate-sensitive region of significant importance in paleoclimatic reconstruction. However, the reconstructed climatic variations based on δ13 Corg in aeolian sediments in the QHL Basin in the northeastern Qinghai-Tibet Plateau (QTP) are lacking, and their paleoclimatic significance remains poorly understood. By conducting δ13 Corg measurements on the Niaodao (ND) aeolian profile near QHL, we reconstructed the paleoclimate changes of 11 ka–present. The variation range of the δ13 Corg values in the ND profile indicated the terrestrial ecosystems were not the sole contributor to lacustrine organic matter. The δ13 Corg values are an indicator of historical temperature changes in the study area, exhibiting similar trends with the reconstruction of Chinese summer temperatures, East Asian air temperature, global temperature, and Northern Hemisphere summer insolation at 37° N. The temperature increased with high frequency and amplitude oscillations, with strong aeolian activity and low total organic carbon accumulation during the Early Holocene. The temperature was maintained at a high and stable level, with the weakest aeolian activity and intensified pedogenesis during the Middle Holocene. The temperature decreased at a high rate, with renewed aeolian activity and weak pedogenesis during the Late Holocene. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
36. Holocene Paleohydrological Changes Reflected in Lake-Level Fluctuations in Lake Annecy (French Pre-Alps): Climatic Significance and Archeological Implications.
- Author
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Magny, Michel, Morin, Eymeric, Vérot, Agnès, Richard, Hervé, Marguet, André, Brigand, Robin, Gabayet, Franck, Hinschberger, Florent, Mouthon, Jacques, and Thirault, Eric
- Subjects
HOLOCENE Epoch ,WATERSHEDS ,FOSSIL collection ,LAKES ,CLIMATE change ,FRESH water - Abstract
Lakes are threatened by contemporary climate change and human activities. Paleohydrological records provide important evidence for developing scenarios for future changes in the availability of freshwater resources. This study presents a synthesis of a sedimentological, archeological, and chronological dataset collected from Lake Annecy (eastern France) to reconstruct a lake-level record documenting the whole Holocene. This dataset shows a pronounced minimum in the lake level during the Holocene thermal maximum (HTM) (ca. 9000–7000 cal BP), preceded by a general lowering trend (early Holocene), and followed by a general rising trend (Neoglacial). On both the millennial and centennial scales, the Lake Annecy record appears to match the regional pattern of Holocene lake-level fluctuations established for West-Central Europe. In agreement with other extra-regional paleoclimatic records, it shows the dominant influence of orbital forcing. The high magnitude of the lake-level lowering (more than 5 m) during the HTM, with a 2–2.5 °C difference between the HTM and the pre-industrial mean summer temperatures, suggests possible drastic lake-level lowering phases in the near future depending on the IPCC scenarios following climate change. This would mean dramatic impacts on human activities and the preservation of exceptional archeological remains in regional lake basins. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
37. Palaeoenvironmental changes since the Last Glacial Maximum: Patterns, timing and dynamics throughout South America.
- Author
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Fontana, Sonia L, Bianchi, María Martha, and Bennett, KD
- Subjects
CLIMATE change ,HOLOCENE Epoch ,PALEOECOLOGY ,QUATERNARY Period ,VEGETATION & climate ,OSCILLATIONS - Abstract
The vast diversity of present vegetation and environments that occur throughout South America (12°N to 56°S) is the result of diverse processes that have been operating and interacting at different spatial and temporal scales. Global factors, such as the concentration of CO2 in the atmosphere, may have been significant for high altitude vegetation during times of lower abundance, while lower sea levels of glacial stages potentially opened areas of continental shelf for colonisation during a substantial portion of the Quaternary. Latitudinal variation in orbital forcing has operated on a regional scale. The pace of climate change in the tropics is dominated by precessional oscillations of c. 20 kyr, while the high latitudes of the south are dominated by obliquity oscillations of c. 40 kyr. In particular, seasonal insolation changes forced by precessional oscillations must have had important consequences for the distribution limits of species, with potentially different effects depending on the latitude. The availability of taxa, altitude and human impact, among other events, have locally influenced the environments. Disentangling the different forcing factors of environmental change that operate on different timescales, and understanding the underlying mechanisms leads to considerable challenges for palaeoecologists. The papers in this Special Issue present a selection of palaeoecological studies throughout South America on vegetation changes and other aspects of the environment, providing a window on the possible complexity of the nature of transitions and timings that are potentially available. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
38. Holocene bison in the Great Basin, western USA.
- Author
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Grayson, Donald K.
- Subjects
BISON ,AMERICAN bison ,BOVIDAE ,BIOGEOGRAPHY ,CLIMATE change ,PLEISTOCENE stratigraphic geology - Abstract
Bison (Bison bison) were widespread in the eastern and northern parts of the Great Basin (the area of internal drainage in the arid western USA) during the late Holocene, particularly after 1600
14 C yr BP. However, of the four areas within the Great Basin for which there is anecdotal evidence of the historic presence of these animals, only one – south-central Oregon – has provided compelling empirical data in support of that evidence. Bison populations flourished in the area immediately surrounding the basin of Pleistocene Lake Bonneville between c. 1600 and 60014 C yr BP, a fluorescence that seems to have been tied to deeper northwards incursions of monsoonal storms. Once those incursions weakened, bison populations declined substantially in size. The appearance of bison in south-central Oregon after 50014 C yr BP may be a function of the increased winter moisture and cooler temperatures that marked this region during the 'Little Ice Age'. [ABSTRACT FROM AUTHOR]- Published
- 2006
- Full Text
- View/download PDF
39. New dates for earth mounds at Weipa, North Queensland, Australia.
- Author
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BROCKWELL, SALLY, Ó FOGHLÚ, BILLY, FENNER, JACK N., STEVENSON, JANELLE, PROSKE, ULRIKE, and SHINER, JUSTIN
- Subjects
CARBON isotopes ,HOLOCENE Epoch ,CLIMATE change ,ARCHAEOLOGICAL chronology - Abstract
Copyright of Archaeology in Oceania is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2017
- Full Text
- View/download PDF
40. The Impacts of the Middle Holocene High Sea-Level Stand and Climatic Changes on Mangroves of the Jucuruçu River, Southern Bahia – Northeastern Brazil.
- Author
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Fontes, Neuza Araújo, Moraes, Caio A., Cohen, Marcelo C L, Alves, Igor Charles C., França, Marlon Carlos, Pessenda, Luiz C R, Francisquini, Mariah Izar, Bendassolli, José Albertino, Macario, Kita, and Mayle, Francis
- Subjects
HOLOCENE Epoch ,SEA level ,CLIMATE change ,ALLUVIUM - Abstract
The aim of this paper is to evaluate the compatibility between the Holocene relative sea-level (RSL) curves proposed for the Brazilian littoral and mangrove dynamics along a fluvial valley in the state of southern Bahia. This was done integrating geomorphological, sedimentological, palynological, and stable isotopic data from two cores collected at the mouth of the Jucuruçu River and at a site 23 km inland, near the city of Prado, northeastern Brazil. Core PR07, sampled from a fluvial plain at about 4.5±1 m above the RSL, reveals mangrove pollen (5–20%) and estuarine/terrestrial organic matter (δ13C=~–25‰, C/N=7.3–67) between 4.5 m (~7400 cal yr BP) and 1.75 m depth (~5350 cal yr BP). Core PR11, sampled from a mangrove tidal flat, also revealed mangrove pollen taxa (5-28%) since 660 cal yr BP. Core PR07 indicated absence of mangrove pollen and increase of sedimentary organic matter sourced from terrestrial C3 plants (δ13C=~–27‰, C/N=22–159) during the last 5350 cal yr BP. Probably, the changes in vegetation and sedimentary organic matter identified in core PR07 were caused by the combined effects of the RSL fluctuations, with a highstand at about 5350 cal yr BP of 2.7±1.35 m, and changes in fluvial discharge. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
41. Analysis of relationship between soil erosion and lake deposition during the Holocene in Xingyun Lake, southwestern China.
- Author
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Zhao, Hongfei, Zhou, Jie, Sun, Qianli, Delang, Claudio O, Mokhtar, Ali, Ma, Yue, and He, Hongming
- Subjects
- *
SOIL erosion , *HOLOCENE Epoch , *EFFECT of human beings on climate change , *LAKE restoration , *WATERSHEDS - Abstract
Quantifying the relative influences of anthropogenic activities and climate change on soil erosion and deposition during the Holocene, when both forces have been interacting is a complex problem. Analysis of long-term patterns in soil erosion and lake deposition in a basin can provide the basis for untangling the complexities of climate and anthropogenic forcings. In this paper, sedimentary sequences from Xingyun Lake are compared with simulated soil erosion rates in the basin to explore the relationship between river basin soil erosion and lake deposition during the Holocene in Yunnan, China. Modern soil erosion rates are calculated using RUSLE, while Holocene soil erosion rates are estimated using modern rates with reconstructed precipitation and vegetation cover sequences. Through this investigation, we found the following results. First, Holocene vegetation in the lake basin was mainly affected by climate change, and the vegetation experienced the same pattern of changes as the climate. Soil erosion and lake deposition rates, along with changes to vegetation cover, were synchronous with precipitation trends during the Holocene. Second, soil erosion and lake deposition have been exacerbated by human activities, such as deforestation and land reclamation in the Xingyun Lake basin. Finally, this study provides new insights into the effects by anthropogenic impacts and climate forcing on the processes of soil erosion and lake deposition on the millennium scale. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
42. Is Recent Warming Exceeding the Range of the Past 125,000 Years?
- Author
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Esper, Jan, Schulz, Philipp, and Büntgen, Ulf
- Subjects
HOLOCENE Epoch ,MARINE sediments ,GLACIATION ,LAKE sediments ,CLIMATE change ,ICE cores - Abstract
The Intergovernmental Panel on Climate Change (IPCC) concluded that the latest decade was warmer than any multi-century period over the past 125,000 years. This statement rests on a comparison of modern instrumental measurements against the course of past temperatures reconstructed from natural proxy archives, such as lake and marine sediments, and peat bogs. Here, we evaluate this comparison with a focus on the hundreds of proxy records developed by paleoclimatologists across the globe to reconstruct climate variability over the Holocene (12,000 years) and preceded by the Last Glacial Period (125,000 years). Although the existing proxy data provide a unique opportunity to reconstruct low-frequency climate variability on centennial timescales, they lack temporal resolution and dating precision for contextualizing the most recent temperature extremes. While the IPCC's conclusion on the uniqueness of latest-decade warming is thus not supported by comparison with these smoothed paleotemperatures, it is still likely correct as ice core-derived forcing timeseries show that greenhouse gases were not elevated during any pre-instrumental period of the Holocene. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
43. Hydroclimatic changes on multiple timescales since 7800 y BP in the winter precipitation-dominated Central Asia.
- Author
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Liangcheng Tan, Hai Cheng, Dong Li, Orozbaev, Rustam, Yanzhen Li, Hai Xu, Edwards, R. Lawrence, Yougui Song, Le Ma, Fangyuan Lin, Sinha, Ashish, and Zhisheng An
- Subjects
WINTER ,ARID regions ,CLIMATE change ,PALEOCLIMATOLOGY ,GLOBAL warming - Abstract
Central Asia (CA) is one of the world's most significant arid regions, which is markedly impacted by global warming. A better understanding of the dynamical processes governing its Holocene climate variability is critical for a better understanding of possible future impacts of climate change in the region. To date, most of the existing CA paleoclimate records are from the summer precipitation-dominated eastern CA (ECA), with few records from the winter precipitation-dominated western CA (WCA). Here, we present a precisely dated (~6‰) and highly resolved (<4-y) record of hydroclimatic variations from the WCA covering the period between 7,774 and 656 y BP. Utilizing multiple proxies (δ
18 O, δ13 C, and Sr/Ca) derived from a stalagmite from the Fergana Valley, Kyrgyzstan, we reveal a long-term drying trend in WCA, which is in contrast with the wetting trend in ECA. We propose that different responses of winter and summer westerly jets to seasonal solar insolation over the past 8,000 y may have resulted in an antiphased precipitation relationship between the WCA and ECA. Our data contain dominant quasiperiodicities of 1,400, 50 to 70, and 20 to 30 y, indicating close connections between the WCA climate and the North Atlantic. We further identified a series of droughts and pluvials on centennial-to-decadal timescales, which may have influenced regional societies and trans-Eurasian culture exchanges during historical and prehistorical times. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
44. Assessing changes in global fire regimes.
- Author
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Sayedi, Sayedeh Sara, Abbott, Benjamin W., Vannière, Boris, Leys, Bérangère, Colombaroli, Daniele, Romera, Graciela Gil, Słowiński, Michał, Aleman, Julie C., Blarquez, Olivier, Feurdean, Angelica, Brown, Kendrick, Aakala, Tuomas, Alenius, Teija, Allen, Kathryn, Andric, Maja, Bergeron, Yves, Biagioni, Siria, Bradshaw, Richard, Bremond, Laurent, and Brisset, Elodie
- Subjects
FIRE management ,EFFECT of human beings on climate change ,BIOMES ,FIRE ecology ,GRASSLANDS ,CLIMATE sensitivity ,ECOSYSTEM services ,PLANT communities - Abstract
Copyright of Fire Ecology is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2024
- Full Text
- View/download PDF
45. Holocene climate change in the Maoyaba Basin, western Sichuan Plateau
- Author
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Siya ZOU, Junliang JI, Yadong XU, and Ning ZHU
- Subjects
tibetan plateau ,western sichuan plateau ,maoyaba basin ,holocene ,climate change ,Geology ,QE1-996.5 ,Engineering geology. Rock mechanics. Soil mechanics. Underground construction ,TA703-712 - Abstract
Objective The Holocene climate of the Tibetan Plateau (TP) is mainly controlled by midlatitude westerlies, the East Asian monsoon, and the Indian monsoon. Previous studies have identified different patterns of Holocene climate change in different regions of the TP. Holocene climate reconstructions for the entire TP help us comprehensively understand the internal linkages of different factors influencing the climate change in the TP. Methods In this paper, we study the Holocene climate in the eastern TP based on 14C dating, lithology and various proxies from the glaciolacustrine strata in the Maoyaba Basin in Litang County, western Sichuan Plateau. Results The Early-Middle Holocene glaciolacustrine sediments covered the last glacial moraines, and then the alluvial-proluvial fans were common during the Late Holocene in the Maoyaba Basin. The grain size of all samples mainly shows a bimodal size distribution after sieving out >2 mm particles. The content of the grain size below medium silt (< 32 μm) is more than 80%, which may be produced by glacial abrasion. The magnetic susceptibility increases obviously in the paleosol, and the appearance of < 1 μm particle size components may indicate that the strong magnetic minerals were generated by pedogenesis. However, the magnetic susceptibility decreased significantly in the glaciolacustrine sediments, which may be related to the dissolution of magnetic minerals in the reducing environment. Conclusion Comprehensive analysis of the sedimentary environment, grain size, magnetic susceptibility, total organic carbon (TOC) and color parameters indicates that the Maoyaba Basin was temperate and dry in the Early Holocene, warm and wet in the Middle Holocene, and temperate and dry in the Late Holocene. This pattern is consistent with the general trend of the Holocene climate in the eastern TP. The paleosol dated to~2 700 cal.yr. B.P. in the Maoyaba Basin indicates a relatively wet period against the background of cooling and a dry climate in the Late Holocene.
- Published
- 2024
- Full Text
- View/download PDF
46. Evaluating human responses to ENSO driven climate change during the Holocene in northwest Australia through macrobotanical analyses.
- Author
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Dilkes-Hall, India Ella, Balme, Jane, O'Connor, Sue, and Dotte-Sarout, Emilie
- Subjects
- *
HOLOCENE Epoch , *CLIMATE change , *ABORIGINAL Australians , *SOUTHERN oscillation , *ARCHAEOLOGICAL excavations ,EL Nino - Abstract
The Holocene is recognised as a period through which a number of climatic fluctuations and environmental stresses occur—associated with intensifying El Niño–Southern Oscillation (ENSO) climatic conditions from c. 5000 years—contemporaneous with technological and social changes in Australian Aboriginal lifeways. In the Kimberley region of northwest Western Australia, human responses to ENSO driven climate change are most evident archaeologically in technological transformations observed in lithic records, with little research on changes in plant use during this time. Using nine archaeological sites across the Kimberley, this paper synthesises previously published macrobotanical data (Carpenter's Gap 1, Moonggaroonggoo, Mount Behn, and Riwi), reports unpublished data (Brooking Gorge 1, Djuru, and Wandjina rockshelter), and presents results of sites reanalysed for this study (Widgingarri Shelters 1 and 2) to develop a picture of localised and regional patterns of plant use during the Holocene. We conclude that food plants associated with monsoon rainforest environments dominate both mid- and late Holocene macrobotanical records and, although monsoon rainforest likely retreated to some extent because of decreased precipitation during the late Holocene, no human responses associated with ENSO driven climate change occurred in relation to human uses of plants. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
47. Geochemical evidence for Holocene millennial-scale climatic and environmental changes in the south-eastern Mu Us Desert, northern China.
- Author
-
Liu, Bing, Jin, Heling, Sun, Liangying, Sun, Zhong, and Zhao, Shuang
- Subjects
CLIMATE change ,GLOBAL environmental change ,MONSOONS ,OSCILLATIONS ,DESERTS - Abstract
Deserts and sandylands that are located in the semi-arid and arid regions in the middle latitudes of the Northern Hemisphere are usually regarded as environmentally sensitive change belts which respond to global climatic change. In northern China, activation or immobilization of sand dunes is mainly influenced by humid and dry variation and is related to stronger or weaker Asian monsoons. In this paper, the history of Holocene millennial-scale climatic and environmental change is reconstructed by the systematic analysis of the geochemical element contents and parameters, along with the OSL and C chronologies, from the different lithologies of the palaeosol-aeolian sand sequence in the south-eastern Mu Us Desert, northern China. Our results indicate that the region was dominated by a dry climate with intensive aeolian activity before 7.2 ka BP, and there was an optimal humid climate and fixed desert in 7.2-4.6 ka. Afterwards, the dune fields became mobile again as the effective humidity declined. Additionally, six dry events were discovered with times of ~7.2, 7.0-6.8, 6.6-5.7, 4.6-4.1, 3.7-3.5, and 3.3-2.5 ka, which were not only coincident with the intervals of millennial-scale weaker Asian summer monsoons, but also accordant with the cold events evidenced in the ice cores and deep-sea deposits of the high latitudes in the Northern Hemisphere. In general, the Holocene climatic and environmental changes had the characteristics of the 'monsoonal mode' and 'abrupt millennial-scale oscillation' in the Mu Us Desert. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
48. Late-Holocene record of lagoon evolution, climate change, and hurricane activity from southeastern Cuba.
- Author
-
Peros, Matthew, Gregory, Braden, Matos, Felipe, Reinhardt, Eduard, and Desloges, Joseph
- Subjects
LAGOONS ,CLIMATE change ,PALEOENVIRONMENTAL studies ,SEA level ,FORAMINIFERA ,FOSSIL pollen ,ACCELERATOR mass spectrometry - Abstract
A sediment core from a lagoon in southeastern Cuba was the focus of a multi-proxy paleoenvironmental study to investigate lagoon response to sea-level change and climate change and also to infer changes in the frequency of past hurricane strikes. The proxy data examined included benthic foraminifera, fossil pollen, particle size analysis, and macrocharcoal influx values. The core was dated using
137 Cs and accelerator mass spectrometry (AMS) radiocarbon methods. The results show that lagoon formation began approximately 4000 years ago and that the lagoon environment evolved through four phases: (1) from ~4000 to 2800 cal. yr BP, the lagoon was a shallow polyhaline to euryhaline system with limited mangrove coverage; (2) from ~2800 to 2000 cal. yr BP, there was a decrease in salinity which facilitated the expansion of red mangrove; (3) from ~2000 to 1000 cal. yr BP, sea-level rise resulted in an increase in water depth and possibly salinity; and (4) from ~1000 cal. yr BP to the present, water level continued to rise and the mangrove environment diversified. The shift to lower salinity conditions from ~2800 to 2000 cal. yr BP may have been climate driven as similar changes are seen at lagoons elsewhere in Cuba. The particle size data show several periods where sand-sized particles are more abundant; these periods are similar to data from Puerto Rico that document times of relatively frequent hurricanes. This paper shows that coastal lagoons are useful archives of paleoclimatic and paleoenvironmental information in the Caribbean region and that they should be the focus of additional research efforts. [ABSTRACT FROM AUTHOR]- Published
- 2015
- Full Text
- View/download PDF
49. A multi-proxy approach to reconstructing sedimentary environments from the Sperchios delta, Greece.
- Author
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Pechlivanidou, Sofia, Vouvalidis, Konstantinos, Løvlie, Reidar, Nesje, Atle, Albanakis, Konstantinos, Pennos, Christos, Syrides, George, Cowie, Patience, and Gawthorpe, Robert
- Subjects
CLIMATE change ,HOLOCENE paleoclimatology ,SEDIMENTATION & deposition ,PALEOGEOPHYSICS ,DELTAS - Abstract
This paper presents an integrated approach to assess Holocene environmental changes in the Sperchios delta, Sperchios rift, central Greece. A multidisciplinary study was carried out applying established analytical methods as well as exploring new techniques to detect past environmental conditions in a fluvio-deltaic depositional system. A series of six deep boreholes, up to 50 m long, and four shallow cores, up to 6 m long, from across the delta plain, were studied in detail. Sedimentary facies were defined by changes in grain size and macro- and microfaunal composition. Variability in mineral magnetic composition documented by changes in bulk magnetic susceptibility (χ and χ77K/χ293K) and remanence parameters (S−300 and σARM/σSIRM ratios), as well as down-core elemental variations obtained by scanning micro-x-ray fluorescence (µ-XRF), provide constraints on the depositional changes related to the evolution of the Sperchios delta. Correlations between elemental data derived by µ-XRF analyses and grain size were also analyzed and used to further constrain the facies interpretation. Overall, these Holocene sediments reveal a transgressive–regressive succession overlying pre-transgressive terrestrial deposits of Late Pleistocene–Early Holocene age. Furthermore, 13 new 14C radiocarbon dates constrain the transgression rate to be ~3.5 m/yr for the Early Holocene and the regression rate to be ~1 m/yr for the Late Holocene. The Sperchios delta plain developed when the rate of sea-level rise decreased ~6000 cal. yr BP as it has been proposed for the broader area of Aegean Sea. This study demonstrates that the combination of techniques used here provides a powerful way to map out paleoenvironmental changes and thus the 3D stratigraphic architecture of Holocene sedimentary successions. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
50. (Un)Earthing Civilization: Holocene Climate Crisis, City-State Origins and the Birth of Writing.
- Author
-
Clark, Nigel
- Subjects
PALEOCLIMATOLOGY ,NOMADS ,CLIMATE change ,HOLOCENE Epoch ,ARCHAEOLOGY - Abstract
Today, concern about population displacement triggered by climate change is prompting some sovereign states to tighten security measures, as well as inciting ethically and politically motivated calls to relax border controls. This paper explores resonances between the current climate predicament and events in the mid-Holocene. Paleoclimatic and archaeological evidence is reviewed, suggesting that an abrupt turn to cooler, drier weather in the 4th millennium BCE triggered high volume migration to fertile river valleys—most fully documented in Mesopotamia but also visible in other regions around the world. This unprecedented agglomeration of bodies has been linked to the emergence of intensive irrigated agriculture and the rise of city-states. In conversation with the ancient Sumerian Gilgamesh epic, this paper draws upon archaeological research to conceptualize urban wall building and emergent practices of graphical notation as different forms of mediation. Both city walls and early writing, it is argued, deal with the interplay of mobilism and sedentarism, and both 'media' entail tactile, plastic use of local materials—namely riverbank clay. This paper addresses the paradox that the underpinning of 'civilization' by these once experimental media may now be fundamentally restricting socio-political, cultural, cognitive and embodied capacities to engage effectively with climate-driven upheaval. All authors have read and agreed to the published version of the manuscript. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
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