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1
He, Y., Wilfred H. Theakstone, Zhang Zhonglin, et al. "Asynchronous Holocene climatic change across China." Quaternary Research 61, no. 1 (2004): 52–63. http://dx.doi.org/10.1016/j.yqres.2003.08.004.
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A review of Holocene climatic variations in different parts of China shows that they were asynchronous. Proxy data from ice cores, pollen, loess, lacustrine sediments, and changes of sea and lake levels demonstrate that many warm and cold oscillations have occurred in China during the Holocene, including a most important climatic event known as the “Holocene optimum,” a milder and wetter period, and that the duration and amplitude of the optimum period, as well as its start and end times, differed in different parts of China. Uplift of the Tibetan plateau over the past millions of years led to the development of the monsoon climate and to complex atmospheric circulation over continental China during the Holocene. As a result, the Holocene optimum began and terminated earlier in high-altitude regions of western China than at lower elevations in eastern China, and the amplitude of the variations was lower in the east. This suggests that the western higher-altitude areas were more sensitive to climatic change than were the eastern lower-altitude areas. Holocene climatic records in the Dunde and Guliya ice cores do not correspond. Inverse δ18O variations between the two cores indicate that the effects of climate and atmospheric processes on the stable isotopes at the two sites differed. The correlation between the isotopic composition of carbonates in lake deposits in western China and climatic variations is similar to that in the ice cores. The climatic resolution in ice cores and lake sediments is higher than that in other media. The lack of precise correspondence of climatic records constructed on the basis of proxy data from different parts of China is a result of the different locations and elevations of the sampling sites, the different resolutions of the source material, and the varied climatic conditions within China. Further work is needed to confirm both the conclusions and the inferences presented here.
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Weidick, A. "Jakobshavn Isbræ area during the climatic optimum." Rapport Grønlands Geologiske Undersøgelse 155 (January 1, 1992): 67–72. http://dx.doi.org/10.34194/rapggu.v155.8183.
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The GGU glaciological investigations related to hydropower planning north (Pakitsoq) and south (Tiningnilik) of Jakobshavn Isbræ have, together with finds and dating of marine subfossils, furnished information on the history of the ice margin changes during and since the Holocene climatic optimum. The paper attempts to reconstruct the ice margin conditions and surroundings during the Holocene climatic optimum on the basis of this information.
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NIELSEN, LISBETH T., GUðFINNA AÐALGEIRSDÓTTIR, VASILEIOS GKINIS, ROMAN NUTERMAN, and CHRISTINE S. HVIDBERG. "The effect of a Holocene climatic optimum on the evolution of the Greenland ice sheet during the last 10 kyr." Journal of Glaciology 64, no. 245 (2018): 477–88. http://dx.doi.org/10.1017/jog.2018.40.
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ABSTRACTThe Holocene climatic optimum was a period 8–5 kyr ago when annual mean surface temperatures in Greenland were 2–3°C warmer than present-day values. However, this warming left little imprint on commonly used temperature proxies often used to derive the climate forcing for simulations of the past evolution of the Greenland ice sheet. In this study, we investigate the evolution of the Greenland ice sheet through the Holocene when forced by different proxy-derived temperature histories from ice core records, focusing on the effect of sustained higher surface temperatures during the early Holocene. We find that the ice sheet retreats to a minimum volume of ~0.15–1.2 m sea-level equivalent smaller than present in the early or mid-Holocene when forcing an ice-sheet model with temperature reconstructions that contain a climatic optimum, and that the ice sheet has continued to recover from this minimum up to present day. Reconstructions without a warm climatic optimum in the early Holocene result in smaller ice losses continuing throughout the last 10 kyr. For all the simulated ice-sheet histories, the ice sheet is approaching a steady state at the end of the 20th century.
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Yang, Xunlin, Hong Yang, Baoyan Wang, et al. "Early-Holocene monsoon instability and climatic optimum recorded by Chinese stalagmites." Holocene 29, no. 6 (2019): 1059–67. http://dx.doi.org/10.1177/0959683619831433.
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The timing and duration of the Holocene East Asian summer monsoon (EASM) maximum and the interpretation of Chinese stalagmite δ18O records have long been disputed. Notably, interpretations of Holocene EASM variations are frequently based on a single record or study area and are often contradictory. In this study, we conducted stable isotope analyses of four Holocene stalagmites from Chongqing, southwest China. The results reveal differences in the timing of the Holocene EASM maximum and to try to resolve the inconsistency we analyzed and statistically integrated a total of 16 Holocene stalagmite records from 14 caves in the EASM region. The resulting synthesized Holocene stalagmite δ18O (δ18Osyn) record is in agreement with other EASM records and confirms that stalagmite δ18O records are a valid indicator of EASM intensity, rather of local precipitation amount. The δ18Osyn record shows that the EASM intensified rapidly from the onset of the early Holocene; notably, however, there were distinct EASM oscillations in the early Holocene, consisting of three abrupt millennial-scale events. This indicates that, contrary to several previous interpretations, the early Holocene EASM was unstable. Subsequently, during 8–6 kyr BP, the EASM was relatively stable and strong, with the strongest monsoon occurring during 8–7 kyr BP. This evidence of a stable and strong mid-Holocene EASM in eastern China is in accord with the classical view of a mid-Holocene Optimum in China.
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Jin, Zhang-Dong, Yanhong Wu, Xiaohui Zhang, and Sumin Wang. "Role of late glacial to mid-Holocene climate in catchment weathering in the central Tibetan Plateau." Quaternary Research 63, no. 2 (2005): 161–70. http://dx.doi.org/10.1016/j.yqres.2004.09.012.
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The lightness (L*) and concentrations of Rb, Sr and organic carbon (Corg) have been measured in the age-constrained lake sediment cores recovered from Co Ngoin in the central Tibetan Plateau. Dissolved Sr flux is a dominant control on the variation of Rb/Sr ratios in the sediments. Variations in color and geochemical proxies of Co Ngoin sediments display a continuous history of late glacial to mid-Holocene chemical versus physical weathering intensity in response to past climatic changes between approximately 13,500 and 4500 cal yr B.P. A lower chemical weathering under a late glacial climate was followed by a higher weathering during the Holocene Optimum. Weathering intensity in the central Tibetan Plateau catchment also responds to well-known climatic events, such as the Younger Dryas (YD), and possibly the Holocene Event 5 (HE-5). Although there are differences in time or duration of the climatic events, many of the well-known late glacial to mid-Holocene events occurred in high-elevation Co Ngoin where atmospheric circulation might play a hemispherical role in climatic forcing. The sediment hiatus since c. 4200 14C yr B.P. in the Co Ngoin indicates a period of desiccation that was probably associated with a sharp decrease in summer monsoon strength. Our lascustrine results not only imply catchment weathering variations in response to late glacial to mid-Holocene climatic conditions in the central plateau, but also provide further evidence for global connections between regional climates.
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Zhang, Jingwei, Xinggong Kong, Kan Zhao, et al. "Centennial-scale climatic changes in Central China during the Holocene climatic optimum." Palaeogeography, Palaeoclimatology, Palaeoecology 558 (November 2020): 109950. http://dx.doi.org/10.1016/j.palaeo.2020.109950.
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Nazarova, L. B., N. G. Razjigaeva, B. Diekmann, et al. "Reconstruction holocene environmental changes in North-Western Pacific in relation to paleorecord from Shikotan Island." Доклады Академии наук 486, no. 2 (2019): 212–16. http://dx.doi.org/10.31857/s0869-56524862212-216.
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Results of a paleolimnological investigated of a well-dated lake sediment section from Shikotan Island (Southern Kurils) showed that from ca 8.0 to 5.8 cal ka BP warm and humid period corresponding to middle Holocene optimum took place. Cooling thereafter corresponds to Neoglacial. A reconstructed from ca 0.9 to ca 0.58 cal ka BP warm period can be correlated to a Medieval Warm Period. Cooling after 0.58 cal ka BP can be correlated with the LIA. Marine regression stages were identified at ca 6.2-5.9, 5.5-5.1 and 1.07-0.36 cal ka BP. The general chronology of major climatic events of Holocene in the island is in accordance with the climate records from the North Pacific region. Revealed spatial differences in timing and magnitude of the Late Holocene climatic episodes (LIA, MWP) within region needs further investigations.
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Janz, Lisa, Arlene M. Rosen, Dashzeveg Bukhchuluun, and Davaakhuu Odsuren. "Zaraa Uul: An archaeological record of Pleistocene-Holocene palaeoecology in the Gobi Desert." PLOS ONE 16, no. 4 (2021): e0249848. http://dx.doi.org/10.1371/journal.pone.0249848.
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Environmentally-based archaeological research at Zaraa Uul, including zooarchaeology, phytolith analysis, and radiocarbon dating, is the first of its kind in Mongolia and presents critical new insight on the relationship between periods of occupational intensity and climatic amelioration from the earliest anatomically modern humans to the adoption of pastoralism. The palaeoenvironmental and faunal record of Zaraa Uul show that Early-Middle Holocene hydrology and species distributions were distinct from all other periods of human occupation. Holocene hunter-gatherers inhabited an ecosystem characterized by extensive marshes, riparian shrub and arboreal vegetation along the hill slopes and drainages. The exploitation of species associated with riparian and wetland settings supports the hypothesis of, but suggests an earlier timing for, oasis-based logistical foraging during the Early-Middle Holocene of arid Northeast Asia. The onset of wetter conditions at 8500 cal BP agrees with other regional studies, but multiple lines of evidence present the first integrated field- and laboratory-based record of human-environment relationships in arid East Asia during the Holocene Climatic Optimum. We compare it to Late Pleistocene climatic amelioration, and highlight specific responses of the hydrological, vegetative and faunal communities to climate change in arid Northeast Asia.
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Nahm, Wook-Hyun, Jin Kwan Kim, Ju-Yong Kim, Sangheon Yi, Jaesoo Lim, and Jin Cheul Kim. "The Holocene climatic optimum in Korea: Evidence from wetland records." Palaeogeography, Palaeoclimatology, Palaeoecology 376 (April 2013): 163–71. http://dx.doi.org/10.1016/j.palaeo.2013.02.033.
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Baroni, Carlo, and Giuseppe Orombelli. "The Alpine “Iceman” and Holocene Climatic Change." Quaternary Research 46, no. 1 (1996): 78–83. http://dx.doi.org/10.1006/qres.1996.0046.
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The finding of a prehistoric mummified corpse at the upper edge of the accumulation area of an alpine glacier, together with its unique set of artifacts, provided new information on glacier dimensions during the little-known phases of major glacier shrinkage that characterized the warmest parts of the Holocene. The sudden burial of the corpse in a permanent snow cover occurred 5300–5050 cal yr B.P., indicating a significant climatic change that induced glacier expansion at the beginning of Neoglaciation. New geomorphologic data and two AMS 14C ages from buried soils suggest that the present glacier size, following over 100 yr of shrinkage, is comparable to that immediately preceding Neoglaciation. Therefore, we can deduce that the current global climatic warming may have interrupted the environmental conditions prevailing in the Alps during Neoglacial time, restoring characteristics similar to those prevailing during the climatic optimum that were never achieved during the second half of the Holocene.
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Van Tatenhove, Frank G. M., Adeline Fabre, Ralf Greve, and Philippe Huybrechts. "Modelled ice-sheet margins of three Greenland ice-sheet models compared with a geological record from ice-marginal deposits in central West Greenland." Annals of Glaciology 23 (1996): 52–58. http://dx.doi.org/10.1017/s0260305500013252.
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Ice-sheet modelling is an essential tool for estimating the effect of climate change on the Greenland ice sheet. The large spatial and long-term temporal scales of the ice-sheet model limits the amount of data which can be used to test model results. The geological record is useful because it provides test material on the time-scales typical for the memory of ice sheets (millennia). This paper compares modelled ice-margin positions with a geological scenario of ice-margin positions since the Last Glacial Maximum to the present in West Greenland. Morphological evidence of ice-margin positions is provided by moraines. Moraine systems are dated by 14C-dated marine shells and terrestrial peat. Three Greenland ice-sheet models are compared. There are distinct differences in modelled ice-margin positions between the models and between model results and the geological record. Disagreement between models and the geological record in the near-coastal area is explained by the inadequate treatment of marginal processes in a tide-water environment. A smaller than present ice sheet around the warm period in the Holocene (Holocene climatic optimum) only occurs if such a period appears in the forcing (ice-core record) or used temporal resolution. Smoothing of the GRIP record with a 2000 year average eliminates the climatic signal related to the Holocene climatic optimum. This underlines the importance of short-term and medium-term variations (decades, centuries) in climatic variables in determining ice-margin positions in the past but also in the future.
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Van Tatenhove, Frank G. M., Adeline Fabre, Ralf Greve, and Philippe Huybrechts. "Modelled ice-sheet margins of three Greenland ice-sheet models compared with a geological record from ice-marginal deposits in central West Greenland." Annals of Glaciology 23 (1996): 52–58. http://dx.doi.org/10.3189/s0260305500013252.
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Ice-sheet modelling is an essential tool for estimating the effect of climate change on the Greenland ice sheet. The large spatial and long-term temporal scales of the ice-sheet model limits the amount of data which can be used to test model results. The geological record is useful because it provides test material on the time-scales typical for the memory of ice sheets (millennia). This paper compares modelled ice-margin positions with a geological scenario of ice-margin positions since the Last Glacial Maximum to the present in West Greenland. Morphological evidence of ice-margin positions is provided by moraines. Moraine systems are dated by 14C-dated marine shells and terrestrial peat. Three Greenland ice-sheet models are compared. There are distinct differences in modelled ice-margin positions between the models and between model results and the geological record. Disagreement between models and the geological record in the near-coastal area is explained by the inadequate treatment of marginal processes in a tide-water environment. A smaller than present ice sheet around the warm period in the Holocene (Holocene climatic optimum) only occurs if such a period appears in the forcing (ice-core record) or used temporal resolution. Smoothing of the GRIP record with a 2000 year average eliminates the climatic signal related to the Holocene climatic optimum. This underlines the importance of short-term and medium-term variations (decades, centuries) in climatic variables in determining ice-margin positions in the past but also in the future.
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Oh, Hyuntaik, and Ho-Jeong Shin. "Climatic classification over asia during the middle holocene climatic optimum based on PMIP models." Journal of Earth Science 27, no. 1 (2016): 123–29. http://dx.doi.org/10.1007/s12583-016-0622-7.
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Masson, Valérie, Françoise Vimeux, Jean Jouzel, et al. "Holocene Climate Variability in Antarctica Based on 11 Ice-Core Isotopic Records." Quaternary Research 54, no. 3 (2000): 348–58. http://dx.doi.org/10.1006/qres.2000.2172.
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A comparison is made of the Holocene records obtained from water isotope measurements along 11 ice cores from coastal and central sites in east Antarctica (Vostok, Dome B, Plateau Remote, Komsomolskaia, Dome C, Taylor Dome, Dominion Range, D47, KM105, and Law Dome) and west Antarctica (Byrd), with temporal resolution from 20 to 50 yr. The long-term trends possibly reflect local ice sheet elevation fluctuations superimposed on common climatic fluctuations. All the records confirm the widespread Antarctic early Holocene optimum between 11,500 and 9000 yr; in the Ross Sea sector, a secondary optimum is identified between 7000 and 5000 yr, whereas all eastern Antarctic sites show a late optimum between 6000 and 3000 yr. Superimposed on the long time trend, all the records exhibit 9 aperiodic millennial-scale oscillations. Climatic optima show a reduced pacing between warm events (typically 800 yr), whereas cooler periods are associated with less-frequent warm events (pacing >1200 yr).
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Orlova, Lyubov A., and Valentina S. Zykina. "Radiocarbon Dating of Buried Holocene Soils in Siberia." Radiocarbon 44, no. 1 (2002): 113–22. http://dx.doi.org/10.1017/s0033822200064717.
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We have constructed a detailed chronological description of soil formation and its environments with data obtained on radiocarbon ages, palynology, and pedology of the Holocene buried soils in the forest steppe of western and central Siberia. We studied a number of Holocene sections, which were located in different geomorphic situations. Radiocarbon dating of materials from several soil horizons, including soil organic matter (SOM), wood, peat, charcoal, and carbonates, revealed three climatic periods and five stages of soil formation in the second part of the Holocene. 14C ages of approximately 6355 BP, 6020 BP, and 5930 BP showed that the longest and most active stage is associated with the Holocene Climatic Optimum, when dark-grey soils were formed in the forest environment. The conditions of birch forest steppe favored formation of chernozem and associated meadow-chernozem and meadow soils. Subboreal time includes two stages of soil formation corresponding to lake regressions, which were less intense than those of the Holocene Optimum. The soils of that time are chernozem, grassland-chernozem, and saline types, interbedded with thin peat layers 14C dated to around 4555 B P, 4240 BP and 3480 BP, and 3170 B P. Subatlantic time includes two poorly developed hydromorphic paleosols formed within inshore parts of lakes and chernozem-type automorphic paleosol. The older horizon was formed during approximately 2500–1770 BP, and the younger one during approximately 1640–400 B P. The buried soils of the Subatlantic time period also attest to short episodes of lake regression. The climate changes show an evident trend: in the second part of the Atlantic time period it was warmer and drier than at present, and in the Subboreal and Subatlantic time periods the climate was cool and humid.
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Feng, Z. D., C. B. An, and H. B. Wang. "Holocene climatic and environmental changes in the arid and semi-arid areas of China: a review." Holocene 16, no. 1 (2006): 119–30. http://dx.doi.org/10.1191/0959683606hl912xx.
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This paper reviews recently published literature, most of which was published in Chinese, and searches for regional patterns of Holocene changes useful in depicting global patterns. The Holocene in the Xinjiang region can be divided into three stages: a warming and dry early stage (from 11 10 to 8-7 ka BP), a warm and wet middle stage (from 8-7 to 4.5-3 ka BP) and a fluctuating cool and dry late stage (since 4.5-3 ka BP). The Holocene in the northern Tibetan Plateau can also be divided into three stages: a warming and wet stage (from 10.5-10 to 5-4 ka BP), followed by a variable drying and probably warm stage (5-4 to 3 ka BP) and ending with a cool and dry stage (since 3 ka BP). In the Inner Mongolian Plateau, the early Holocene (from 10.5-9.5 to 8-7.5 ka BP) was warming and dry, and a warm and wet climate occurred from 7.5 to 3.5, during which the best time was 6.3-3.8 ka BP; the climate has been variably drying and probably cooling since 3.5 ka BP. In the northwestern part of the Loess Plateau, several Holocene palaeosols have been identified (10-9, 7.5-5, 4-3 and 2.7-2 ka BP) with the 7.5-5 ka BP palaeosol being most strongly expressed. The best-developed palaeosol-equivalent in major valleys is a swamp-wetland facies deposited between 8885 and 3805 14C yr BP under an extremely wet regime. The climate has fluctuated significantly at least three times around a dry and probably cool regime after the swamp-wetland facies-depositional period. Our summary shows that the Holocene Climatic Optimum occurred nearly contemporaneously (8-5 ka BP) at all sites in the Xinjiang region, in the Inner Mongolian Plateau and in the northwestern part of the Loess Plateau. A warming and wet early Holocene (10-8 ka BP) in the northern Tibetan Plateau is most likely related to high effective soil moisture resulting from snow and ice melting. We propose here that the middle Holocene Climatic Optimum (8-5 ka BP) in arid to semi-arid China was primarily a delayed response of the low latitude oceans to high latitude peak insolation (9-8 ka BP).
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Mitchell, Peter. "Practising archaeology at a time of climatic catastrophe." Antiquity 82, no. 318 (2008): 1093–103. http://dx.doi.org/10.1017/s0003598x00097805.
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The term 'catastrophe' in my title is not chosen idly, but reflects the now well-established fact that Earth is experiencing (anthropogenic) climate change at a rate and scale unparalleled in human history (IPCC 2007a). Dramatic events such as the terrorist attacks of 11 September 2001 are so unexpected that one retains a clear memory of precisely when and where one learned of them. Regrettably, climate change is subtler, its effects slower, its consequences less immediately obvious. Yet something of the same is true. In my own case, I vividly recall the moment when I first grasped what it might mean. At the 1993 Kimberley meeting of the Southern African Society for Quaternary Research (SASQUA), a presenter commented that her palaeoenvironmental research, which reached back through the Holocene, might, perhaps, be relevant to modelling future climatic change. Back came the comment from another participant that the Holocene climatic 'optimum' was far from relevant; a bestcase analogue might instead be the conditions prevailing during the Pliocene, 5.3-1.8 million years ago.
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Tarrats, Pol, Oliver Heiri, Blas Valero-Garcés, et al. "Chironomid-inferred Holocene temperature reconstruction in Basa de la Mora Lake (Central Pyrenees)." Holocene 28, no. 11 (2018): 1685–96. http://dx.doi.org/10.1177/0959683618788662.
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We present the first Holocene chironomid-based summer temperature reconstruction for the Iberian Peninsula. A sequence from the shallow mountain lake Basa de la Mora (1914 m a.s.l., Central Pyrenees) was analysed and the reconstruction was performed by means of a merged Norwegian–Swiss chironomid calibration dataset. The presence of a multiproxy study conducted in the same lake, as well as other available regional temperature estimations, allowed the comparison of our results with distinct local and regional records in order to disentangle different temperature and hydrological and seasonal patterns throughout the Holocene. The sampling resolution does not allow analysing rapid climatic oscillations, but provides insights into general Holocene trends. Overall, we found increasing temperatures at the onset of the Holocene, reaching the highest values during the Holocene Climatic Optimum (in our record ca. 7800 cal. yr BP). High temperatures were observed until ca. 6000 yr BP, when a decline of ca. 1.5ºC was inferred and the lowest temperature values throughout the sequence were reconstructed during the period 4200–2000 cal. yr BP coinciding with the first part of the late Holocene. Finally, an increasing trend in temperature values characterized the last two millennia, although we interpret this reconstructed temperature rise with caution as distinguishing between climatic and anthropogenic influences on the chironomid record in this youngest section of the Holocene is challenging.
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Zhang, Zhiping, Jianbao Liu, Jie Chen, et al. "Holocene climatic optimum in the East Asian monsoon region of China defined by climatic stability." Earth-Science Reviews 212 (January 2021): 103450. http://dx.doi.org/10.1016/j.earscirev.2020.103450.
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Oerlemans, J., J. Jania, and L. Kolondra. "Application of a minimal glacier model to Hansbreen, Svalbard." Cryosphere 5, no. 1 (2011): 1–11. http://dx.doi.org/10.5194/tc-5-1-2011.
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Abstract. Hansbreen is a well studied tidewater glacier in the southwestern part of Svalbard, currently about 16 km long. Since the end of the 19th century it has been retreating over a distance of 2.7 km. In this paper the global dynamics of Hansbreen are studied with a minimal glacier model, in which the ice mechanics are strongly parameterised and a simple law for iceberg calving is used. The model is calibrated by reconstructing a climate history in such a way that observed and simulated glacier length match. In addition, the calving law is tuned to reproduce the observed mean calving flux for the period 2000–2008. Equilibrium states are studied for a wide range of values of the equilibrium line altitude. The dynamics of the glacier are strongly nonlinear. The height-mass balance feedback and the water depth-calving flux feedback give rise to cusp catastrophes in the system. For the present climatic conditions Hansbreen cannot survive. Depending on the imposed climate change scenario, in AD 2100 Hansbreen is predicted to have a length between 10 and 12 km. The corresponding decrease in ice volume (relative to the volume in AD 2000) is 45 to 65%. Finally the late-Holocene history of Hansbreen is considered. We quote evidence from dated peat samples that Hansbreen did not exist during the Holocene Climatic Optimum. We speculate that at the end of the mid-Holocene Climatic Optimum Hansbreen could advance because the glacier bed was at least 50 m higher than today, and because the tributary glaciers on the western side may have supplied a significant amount of mass to the main stream. The excavation of the overdeepening and the formation of the shoal at the glacier terminus probably took place during the Little Ice Age.
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Oerlemans, J., J. Jania, and L. Kolondra. "Application of a minimal glacier model to Hansbreen, Spitsbergen." Cryosphere Discussions 4, no. 3 (2010): 949–79. http://dx.doi.org/10.5194/tcd-4-949-2010.
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Abstract. Hansbreen is a well studied tidewater glacier in the southwestern part of Spitsbergen, currently about 16 km long. Since the end of the 19th century it has been retreating over a distance of 2.7 km. In this paper the global dynamics of Hansbreen are studied with a minimal glacier model, in which the ice mechanics are strongly parameterised and a simple law for iceberg calving is used. The model is calibrated by reconstructing a climate history in such a way that observed and simulated glacier length match. In addition, the calving law is tuned to reproduce the observed mean calving flux for the period 2000–2008. Equilibrium states are studied for a wide range of values of the equilibrium line altitude. The dynamics of the glacier are strongly nonlinear. The height-mass balance feedback and the water depth – calving flux feedback give rise to cusp catastrophes in the system. For the present climatic conditions Hansbreen cannot survive. Depending on the imposed climate change scenario, in AD 2100 Hansbreen is predicted to have a length between 10 and 12 km. The corresponding decrease in ice volume (relative to the volume in AD 2000) is 45 to 65%. Finally the late-Holocene history of Hansbreen is considered. We quote evidence from dated peat samples that Hansbreen did not exist during the Holocene Climatic Optimum. We speculate that at the end of the mid-Holocene Climatic Optimum Hansbreen could advance because the glacier bed was at least 50 m higher than today, and because the tributary glaciers on the western side may have supplied a significant amount of mass to the main stream. The excavation of the overdeepening and the formation of the shoal at the glacier terminus probably took place during the Little Ice Age.
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Arnold, Luc, François-Marie Bréon, and Simon Brewer. "The Earth as an extrasolar planet: the vegetation spectral signature today and during the last Quaternary climatic extrema." International Journal of Astrobiology 8, no. 2 (2009): 81–94. http://dx.doi.org/10.1017/s1473550409004406.
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AbstractThe so-called vegetation red-edge (VRE), a sharp increase in the reflectance around 700 nm, is a characteristic of vegetation spectra, and can therefore be used as a biomarker if it can be detected in an unresolved extrasolar Earth-like planet integrated reflectance spectrum. Here, we investigate the potential for the detection of vegetation spectra during the last Quaternary climatic extrema, the Last Glacial Maximum (LGM) and the Holocene optimum, for which past climatic simulations have been made. By testing the VRE detectability during these extrema, when Earth's climate and biomes maps were different from today, we are able to test the vegetation detectability on a terrestrial planet different from our modern Earth. Data from the Biome3.5 model have been associated to visible Global Ozone Monitoring Experiment (GOME) spectra for each biome and cloud cover to derive Earth's integrated spectra for given Earth phases and observer positions. The VRE is then measured. Results show that the vegetation remains detectable during the last climatic extrema. Compared to the current Earth, the Holocene optimum, with a greener Sahara, slightly increases the mean VRE on one hand, while on the other hand, the large ice cap over the northern hemisphere during the LGM decreases vegetation detectability. We finally discuss the detectability of the VRE in the context of recently proposed space missions.
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Ran, Lihua, Hui Jiang, Karen Luise Knudsen, Jón Eiríksson, and Zhiwen Gu. "Diatom response to the Holocene climatic optimum on the North Icelandic shelf." Marine Micropaleontology 60, no. 3 (2006): 226–41. http://dx.doi.org/10.1016/j.marmicro.2006.05.002.
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Bostock, H. C., J. G. Prebble, G. Cortese, et al. "Paleoproductivity in the SW Pacific Ocean During the Early Holocene Climatic Optimum." Paleoceanography and Paleoclimatology 34, no. 4 (2019): 580–99. http://dx.doi.org/10.1029/2019pa003574.
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Schild, Romuald, and Fred Wendorf. "Geoarchaeology of the Holocene climatic optimum at Nabta Playa, Southwestern Desert, Egypt." Geoarchaeology 16, no. 1 (2000): 7–28. http://dx.doi.org/10.1002/1520-6548(200101)16:1<7::aid-gea3>3.0.co;2-j.
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Triantaphyllou, Maria V., Alexandra Gogou, Margarita D. Dimiza, et al. "Holocene Climatic Optimum centennial-scale paleoceanography in the NE Aegean (Mediterranean Sea)." Geo-Marine Letters 36, no. 1 (2015): 51–66. http://dx.doi.org/10.1007/s00367-015-0426-2.
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Mendieta, Kalindhi Larios, Stefan Gerber, and Mark Brenner. "Florida wildfires during the Holocene Climatic Optimum (9000–5000 cal yr BP)." Journal of Paleolimnology 60, no. 1 (2018): 51–66. http://dx.doi.org/10.1007/s10933-018-0023-2.
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Kluge, T., H. P. Affek, T. Marx та ін. "Reconstruction of drip-water δ<sup>18</sup>O based on calcite oxygen and clumped isotopes of speleothems from Bunker Cave (Germany)". Climate of the Past Discussions 8, № 4 (2012): 2853–92. http://dx.doi.org/10.5194/cpd-8-2853-2012.
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Abstract. The geochemical signature of many speleothems used for reconstruction of past continental climates is affected by kinetic isotope fractionation. This limits quantitative paleoclimate reconstruction and, in cases where the kinetic fractionation varies with time, also affects relative paleoclimate interpretations. In carbonate archive research, clumped isotope thermometry is typically used as proxy for absolute temperatures. In the case of speleothems, however, clumped isotopes provide a sensitive indicator for disequilibrium effects. The extent of kinetic fractionation co-varies in Δ47 and δ18O so that it can be used to account for disequilibrium in δ18O and to extract the past drip-water composition. Here we apply this approach to stalagmites from Bunker Cave (Germany) and calculate drip-water δ18Ow values for the Eemian, Marine Isotope Stage (MIS) 3, and the Holocene, relying on independent temperature estimates and accounting for disequilibrium. Applying the co-variation method to modern calcite precipitates yields drip-water δ18Ow values in agreement with modern cave drip-water δ18Ow of −7.9 ± 0.3‰, despite large and variable disequilibrium effects in both calcite δ18Oc and Δ47. Reconstructed paleo-drip-water δ18Ow values are lower during colder periods (e.g., MIS 3: −8.5 ± 0.4‰ and the early Holocene at 11 kyr: −9.3 ± 0.1‰) and show higher values during warmer climatic periods (e.g., the Eemian: −7.5 ± 0.2‰ and the Holocene Climatic Optimum: −7.2 ± 0.3‰). This new approach offers a unique possibility for quantitative climate reconstruction including the assessment of past hydrological conditions while accounting for disequilibrium effects.
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Kluge, T., H. P. Affek, T. Marx та ін. "Reconstruction of drip-water δ<sup>18</sup>O based on calcite oxygen and clumped isotopes of speleothems from Bunker Cave (Germany)". Climate of the Past 9, № 1 (2013): 377–91. http://dx.doi.org/10.5194/cp-9-377-2013.
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Abstract. The geochemical signature of many speleothems used for reconstruction of past continental climates is affected by kinetic isotope fractionation. This limits quantitative paleoclimate reconstruction and, in cases where the kinetic fractionation varies with time, also affects relative paleoclimate interpretations. In carbonate archive research, clumped isotope thermometry is typically used as proxy for absolute temperatures. In the case of speleothems, however, clumped isotopes provide a sensitive indicator for disequilibrium effects. The extent of kinetic fractionation co-varies in Δ47 and δ18O so that it can be used to account for disequilibrium in δ18O and to extract the past drip-water composition. Here we apply this approach to stalagmites from Bunker Cave (Germany) and calculate drip-water δ18Ow values for the Eemian, MIS3, and the Holocene, relying on independent temperature estimates and accounting for disequilibrium. Applying the co-variation method to modern calcite precipitates yields drip-water δ18Ow values in agreement with modern cave drip-water δ18Ow of −7.9 ± 0.3‰, despite large and variable disequilibrium effects in both calcite δ18Oc and Δ47. Reconstructed paleo-drip-water δ18Ow values are lower during colder periods (e.g., MIS3: −8.6 ± 0.4‰ and the early Holocene at 11 ka: −9.7 ± 0.2‰) and show higher values during warmer climatic periods (e.g., the Eemian: −7.6 ± 0.2‰ and the Holocene Climatic Optimum: −7.2 ± 0.3‰). This new approach offers a unique possibility for quantitative climate reconstruction including the assessment of past hydrological conditions while accounting for disequilibrium effects.
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Larsen, Eiliv, Hans Petter Sejrup, Sigfus J. Johnsen, and Karen Luise Knudsen. "Do Greenland Ice Cores Reflect NW European Interglacial Climate Variations?" Quaternary Research 43, no. 2 (1995): 125–32. http://dx.doi.org/10.1006/qres.1995.1014.
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AbstractThe climatic evolution during the Eemian and the Holocene in western Europe is compared with the sea-surface conditions in the Norwegian Sea and with the oxygen-isotope-derived paleotemperature signal in the GRIP and Renland ice cores from Greenland. The records show a warm phase (ca. 3000 yr long) early in the Eemian (substage 5e). This suggests that the Greenland ice sheet, in general, recorded the climate in the region during this time. Rapid fluctuations during late stage 6 and late substage 5e in the GRIP ice core apparently are not recorded in the climatic proxies from western Europe and the Norwegian Sea. This may be due to low resolution in the terrestrial and marine records and/or long response time of the biotic changes. The early Holocene climatic optimum recorded in the terrestrial and marine records in the Norwegian Sea-NW European region is not found in the Summit (GRIP and GISP2) ice cores. However, this warm phase is recorded in the Renland ice core. Due to the proximity of Renland to the Norwegian Sea, this area is probably more influenced by changes in polar front positions which may partly explain this discrepancy. A reduction in the elevation at Summit during the Holocene may, however, be just as important. The high-amplitude shifts during substage 5e in the GRIP core could be due to Atlantic water oscillating closer to, and also reaching, the coast of East Greenland. During the Holocene, Atlantic water was generally located farther east in the Norwegian Sea than during the Eemian.
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Zhang, E., Y. Wang, W. Sun, and J. Shen. "Holocene Asian monsoon evolution revealed by a pollen record from an alpine lake on the southeastern margin of the Qinghai-Tibetan Plateau, China." Climate of the Past Discussions 11, no. 5 (2015): 4751–86. http://dx.doi.org/10.5194/cpd-11-4751-2015.
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Abstract. We present the results of pollen analyses from a 1105-cm-long sediment core from Wuxu Lake in southwestern China, which depict the variations of the East Asian winter monsoon (EAWM) and the Indian summer monsoon (ISM) during the last 12.3 ka. During the period of 12.3 to 11.3 cal ka BP, the dominance of Betula forest and open alpine shrub and meadow around Wuxu Lake indicates a climate with relatively cold winters and dry summers, corresponding to the Younger Dryas event. Between 11.3 and 10.4 cal ka BP, further expansion of Betula forest and the retreat of alpine shrubs and meadows reflect a greater seasonality with cold winters and gradually increasing summer precipitation. From 10.4 to 4.9 cal ka BP, the dense forest understory, together with the gradual decrease in Betula forest and increase in Tsuga forest, suggest that the winters became warmer and summer precipitation was at a maximum, corresponding to the Holocene climatic optimum. Between 4.9 and 2.6 cal ka BP, Tsuga forest and alpine shrubs and meadows expanded significantly, reflecting relatively warm winters and decreased summer precipitation. Since 2.6 cal ka BP, reforestation around Wuxu Lake indicates a renewed strengthening of the ISM in the late Holocene; however, the vegetation in the catchment may also have been affected by grazing activity during this period. The results of our study are generally consistent with previous findings; however, the timing and duration of the Holocene climatic optimum from different records are inconsistent, reflecting real contrast in local rainfall response to the ISM. Overall, the EAWM is broadly in-phase with the ISM on the orbital timescale, and both monsoons exhibit a trend of decreasing strength from the early to late Holocene, reflecting the interplay of solar insolation receipt between the winter and summer seasons and El Niño Southern Oscillation strength in the tropical Pacific.
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Zhang, Enlou, Yongbo Wang, Weiwei Sun, and Ji Shen. "Holocene Asian monsoon evolution revealed by a pollen record from an alpine lake on the southeastern margin of the Qinghai–Tibetan Plateau, China." Climate of the Past 12, no. 2 (2016): 415–27. http://dx.doi.org/10.5194/cp-12-415-2016.
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Abstract. We present the results of pollen analyses from a 1105 cm long sediment core from Wuxu Lake in southwestern China, which depict the variations of the East Asian winter monsoon (EAWM) and the Indian summer monsoon (ISM) during the last 12.3 ka. During the period of 12.3 to 11.3 cal ka BP, the dominance of Betula forest and open alpine shrub and meadow around Wuxu Lake indicates a climate with relatively cold winters and dry summers, corresponding to the Younger Dryas event. Between 11.3 and 10.4 cal ka BP, further expansion of Betula forest and the retreat of alpine shrubs and meadows reflect a greater seasonality with cold winters and gradually increasing summer precipitation. From 10.4 to 4.9 cal ka BP, the dense forest understory, together with the gradual decrease in Betula forest and increase in Tsuga forest, suggest that the winters became warmer and summer precipitation was at a maximum, corresponding to the Holocene climatic optimum. Between 4.9 and 2.6 cal ka BP, Tsuga forest and alpine shrubs and meadows expanded significantly, reflecting relatively warm winters and decreased summer precipitation. Since 2.6 cal ka BP, reforestation around Wuxu Lake indicates a renewed humid period in the late Holocene; however, the vegetation in the catchment may also have been affected by grazing activity during this period. The results of our study are generally consistent with previous findings; however, the timing and duration of the Holocene climatic optimum from different records are inconsistent, reflecting real contrast in local rainfall response to the ISM. Overall, the EAWM is broadly in-phase with the ISM on the orbital timescale, and both monsoons exhibit a trend of decreasing strength from the early to late Holocene, reflecting the interplay of solar insolation receipt between the winter and summer seasons and El Niño–Southern Oscillation strength in the tropical Pacific.
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Osmont, Dimitri, Michael Sigl, Anja Eichler, Theo M. Jenk, and Margit Schwikowski. "A Holocene black carbon ice-core record of biomass burning in the Amazon Basin from Illimani, Bolivia." Climate of the Past 15, no. 2 (2019): 579–92. http://dx.doi.org/10.5194/cp-15-579-2019.
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Abstract. The Amazon Basin is one of the major contributors to global biomass burning emissions. However, regional paleofire trends remain particularly unknown. Due to their proximity to the Amazon Basin, Andean ice cores are suitable to reconstruct paleofire trends in South America and improve our understanding of the complex linkages between fires, climate and humans. Here we present the first refractory black carbon (rBC) ice-core record from the Andes as a proxy for biomass burning emissions in the Amazon Basin, derived from an ice core drilled at 6300 m a.s.l. from the Illimani glacier in the Bolivian Andes and spanning the entire Holocene back to the last deglaciation 13 000 years ago. The Illimani rBC record displays a strong seasonality with low values during the wet season and high values during the dry season due to the combination of enhanced biomass burning emissions in the Amazon Basin and less precipitation at the Illimani site. Significant positive (negative) correlations were found with reanalyzed temperature (precipitation) data for regions in eastern Bolivia and western Brazil characterized by substantial fire activity. rBC long-term trends indirectly reflect regional climatic variations through changing biomass burning emissions as they show higher (lower) concentrations during warm–dry (cold–wet) periods, in line with climate variations such as the Younger Dryas, the 8.2 ka event, the Holocene Climatic Optimum, the Medieval Warm Period and the Little Ice Age. The highest rBC concentrations of the entire record occurred during the Holocene Climatic Optimum between 7000 and 3000 BCE, suggesting that this exceptionally warm and dry period caused high levels of biomass burning activity, unprecedented in the context of the past 13 000 years. Recent rBC levels, rising since 1730 CE in the context of increasing temperatures and deforestation, are similar to those of the Medieval Warm Period. No decrease in fire activity was observed in the 20th century, in contradiction to global biomass burning reconstructions based on charcoal data.
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Lozhkin, Anatoly, Pavel Minyuk, Marina Cherepanova, Patricia Anderson, and Bruce Finney. "Holocene environments of central Iturup Island, southern Kuril archipelago, Russian Far East." Quaternary Research 88, no. 1 (2017): 23–38. http://dx.doi.org/10.1017/qua.2017.21.
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AbstractTwo lake records document Holocene changes in sea level, vegetation, and climate on the Okhotsk and Pacific sides of central Iturup Island, southern Kuril Islands. The sediment cores originated within tidal flats that subsequently developed into a marine strait which crosscut the island as sea levels rose during the early Holocene. Brackish lagoons and eventually freshwater lakes formed by ~7100 cal yr BP associated with warmer than present conditions. Past vegetation changes indicate a clear Holocene thermal maximum recorded on the Pacific coast but a less distinct optimum on the western shores (~7200–6100 cal yr BP). A gradual cooling toward modern levels occurred ~6100–3500 cal yr BP. Four prominent layers of coarse sediment found in mid- to late Holocene lake deposits may correspond to intervals of climate cooling/dune formation previously documented in coastal sections. Although chronological limitations question the synchronicity of these events across the south Russian Far East, it seems probable that they have a regional signature. However, the mechanisms responsible for Holocene climatic changes are likely the result of complex interactions of hemispheric-scale atmospheric patterns, marine characteristics, and regional feedbacks rather than simply fluctuations in sea levels as suggested in the current interpretative model.
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Dredge, L. A., R. J. Mott, and D. R. Grant. "Quaternary stratigraphy, paleoecology, and glacial geology, Îles de la Madeleine, Quebec." Canadian Journal of Earth Sciences 29, no. 9 (1992): 1981–96. http://dx.doi.org/10.1139/e92-154.
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On the Îles de la Madeleine, a rock platform as much as 20 m asl, locally with clam borings, is correlated to the regional interglacial surface at 2–8 m; its anomalous height may be a consequence of salt tectonics. Overlying lagoonal and paludal organic beds, one with Th/U ages of 89–101 ka, record the Sangamonian climatic optimum (substage 5e), which culminated in forest more thermophilous than that of the Holocene optimum. Overlying littoral gravel and sand, considered analogous to sediments in present-day tombolos, and organic beds with less temperate pollen types were deposited during the marine transgressive climax of substage 5e and thus indicate that sea level remained high after the thermal optimum, as in Holocene time. Cold-based Early Wisconsinan ice, probably centred on the Magdalen Shelf, tectonized bedrock and interglacial beds and deposited till upon them. Periglacial features indicate a subsequent long cold period. An organic bed dating from 11.3 to 10.6 ka records a warm interval followed by cooling. Buried peat, a submerged fossil sea cliff, and barrier beaches record a marine transgression during the late Holocene.
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KIRKUP, HELEN, MARTIN MELLES, and DAMIAN B. GORE. "Late Quaternary environment of southern Windmill Islands, East Antarctica." Antarctic Science 14, no. 4 (2002): 385–94. http://dx.doi.org/10.1017/s0954102002000202.
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Analyses on a sediment core collected from the Windmill Islands, East Antarctica are used to demonstrate that climatic conditions in this region prior to the Last Glacial Maximum were similar to those during the Holocene and that the area was overrun by ice at some stage between 26 kyr BP and the onset of biogenic sedimentation 11 kyr BP. The 10.9 m long core was taken from a marine inlet (epishelf lake) on Peterson Island and is predominantly a sapropel of Holocene age. Material in the lower part of the core includes a till layer lain down during the last glacial in the region and below this till is material which has been dated to 26 kyr BP. Geochemical analyses conducted on the core demonstrate similarities between the Holocene sequence and the preglacial material. The Holocene sequence shows enhanced biogenic production and periods of open water around 4 kyr BP, suggesting a climatic optimum around that time. A subsequent decline in conditions, probably a colder climate with greater extent of sea ice, is evident from 1 kyr BP to the present. The data support results from ice core studies on nearby Law Dome, which suggest there was a period of warming around 11.5 to 9 kyr BP, that recent summer temperatures are low relative to a few centuries ago, and that increasing winter temperatures are the main contributing factor to a recent overall warming in the region.
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Renssen, Hans. "Modelling spatial and temporal variation in the Holocene climatic optimum across the globe." Quaternary International 279-280 (November 2012): 400. http://dx.doi.org/10.1016/j.quaint.2012.08.1265.
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Prebble, J. G., H. C. Bostock, G. Cortese, et al. "Evidence for a Holocene Climatic Optimum in the southwest Pacific: A multiproxy study." Paleoceanography 32, no. 8 (2017): 763–79. http://dx.doi.org/10.1002/2016pa003065.
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Razzhigaeva, N. G., L. A. Ganzei, T. A. Grebennikova, N. I. Belyanina, and L. M. Mokhova. "The manifestations of the Holocene Little Climatic Optimum in the southern Far East." Geography and Natural Resources 35, no. 2 (2014): 173–80. http://dx.doi.org/10.1134/s1875372814020097.
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Evstigneeva, T. A., and N. N. Naryshkina. "The Holocene climatic optimum at the southern coast of the Sea of Japan." Paleontological Journal 44, no. 10 (2010): 1262–69. http://dx.doi.org/10.1134/s0031030110100047.
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Gingele, Franz X. "Holocene climatic optimum in Southwest Africa—evidence from the marine clay mineral record." Palaeogeography, Palaeoclimatology, Palaeoecology 122, no. 1-4 (1996): 77–87. http://dx.doi.org/10.1016/0031-0182(96)00076-4.
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Yu, Ke-Fu, Jian-Xin Zhao, Tung-Sheng Liu, Gang-Jian Wei, Pin-Xian Wang, and Kenneth D. Collerson. "High-frequency winter cooling and reef coral mortality during the Holocene climatic optimum." Earth and Planetary Science Letters 224, no. 1-2 (2004): 143–55. http://dx.doi.org/10.1016/j.epsl.2004.04.036.
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Mott, Robert J. "Sangamonian Forest History and Climate in Atlantic Canada." Articles 44, no. 3 (2007): 257–70. http://dx.doi.org/10.7202/032828ar.
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ABSTRACT Seven of the more than twenty five buried organic deposits in Atlantic Canada assigned to pre-Wisconsinan non-glacial intervals possibly relate to the climatic optimum of the Sangamon Interglaciation, that is substage 5e of the deep-sea oxygen isotope record. These sites are East Bay and Green Point on Cape Breton Island. Addington Forks and East Milford in mainland Nova Scotia. Le Bassin and Portage-du-Cap on the Iles de la Madeleine, Québec, and Woody Cove, Newfoundland. Except for Woody Cove, none of the sites records a complete climatic cycle, and the sequence of events must be pieced together from their disparate records. The spectra, characterized by significant amounts of thermophilous taxa that are not as abundant or present in the region today, are similar in general to Holocene spectra at sites immediately south of the lower Great Lakes. Comparison of the fossil spectra from five sites with modern surface spectra from eastern North America yields modern analogs which, if valid, indicate that the climate in Atlantic Canada during the climatic optimum of the last interglacial interval was more continental in character and considerably warmer than present.
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Li, Yu, Lingmei Xu, Chengqi Zhang, Yuan Liu, Gengrui Zhu, and Xuehua Zhou. "Temporal and spatial evolution of Holocene vegetation and lake hydrological status, China." Holocene 28, no. 5 (2017): 706–20. http://dx.doi.org/10.1177/0959683617744260.
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Studying past climate change has important scientific significance in exploring long-term climatic variability, assessing the nature and human’s contribution to climate warming, and predicting future climate change. Here, we presented a data synthesis of pollen records, organic geochemical proxies, as well as lake-level records, along with numerical climate classification and lake-level simulations to show temporal and spatial evolution of past vegetation and hydrologic change during the Holocene in China. Both geological data and numerical modeling indicated that the evolution of vegetation shows out-of-phase relationships with lake hydrological status in various regions. China as a whole experienced optimal vegetation cover in the mid-Holocene. However, areas dominated by the Asian monsoon and the Westerlies did not uniformly show an early Holocene hydrological optimum. For the Westerlies-controlled regions, optimal conditions prevailed during the mid-Holocene. These apparent contradictions were closely related to various driving factors in different geographical regions. Precipitation has been recognized as a major influence on lake hydrological status of arid and semi-arid in northeast China, whereas in other regions of China, the combined effect of evaporation and precipitation was more influential. Likewise, the limiting factor of vegetation conditions was asynchronous in China, for example, moisture in northwestern China, temperature in the Qinghai-Tibet Plateau, as well as moisture and temperature in the monsoon marginal zones and monsoonal regions. The results provide insights into the underlying climate-forcing mechanisms, and demonstrate a new perspective on Quaternary environment change research.
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Elbakidze, Ekaterina. "Ecological Condition of Diatoms Flora in Holocene Sediments of Razdolnaya River (Far East of Russia)." Advanced Materials Research 726-731 (August 2013): 1475–78. http://dx.doi.org/10.4028/www.scientific.net/amr.726-731.1475.
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The ecological structure of diatoms communities was researched from sediments of the First Razdolnaya river terrace (Southern Primorye). The obtained data allowed to establish climatic rhythmics and the related transgression-regression cycles, are typical for the area of researches. The analysis of the replacement lagoon-marine diatoms complexes by lacustrine, alluvial and marsh ones allow us to establish the amplitudes of the Japan Sea fluctuations and ingression penetration into river valley. The maximum of the ingression penetration (up to 23 km from sea-shore) toward river-valley corresponds to Holocene climatic optimum. The sea level could exceed modern on +3m at this time and influenced on the coastline formation.
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Dudová, Lydie, Petra Hájková, Věra Opravilová, and Michal Hájek. "Holocene history and environmental reconstruction of a Hercynian mire and surrounding mountain landscape based on multiple proxies." Quaternary Research 82, no. 1 (2014): 107–20. http://dx.doi.org/10.1016/j.yqres.2014.04.017.
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AbstractWe discovered the first peat section covering the entire Holocene in the Hrubý Jeseník Mountains, representing an island of unique alpine vegetation whose history may display transitional features between the Hercynian and Carpathian regions. We analysed pollen, plant macrofossils (more abundant in bottom layers), testate amoebae (more abundant in upper layers), peat stratigraphy and chemistry. We found that the landscape development indeed differed from other Hercynian mountains located westward. This is represented byPinus cembraandLarixduring the Pleistocene/Holocene transition, the early expansion of spruce around 10,450 cal yr BP, and survival ofLarixduring the climatic optimum. The early Holocene climatic fluctuations are traced in our profile by species compositions of both the mire and surrounding forests. The mire started to develop as a calcium-rich percolation fen with some species recently considered to be postglacial relicts (Meesia triquetra,Betula nana), shifted into ombrotrophy around 7450 cal yr BP by autogenic succession and changed into a pauperised, nutrient-enriched spruce woodland due to modern forestry activities. We therefore concluded that its recent vegetation is not a product of natural processes. From a methodological viewpoint we demonstrated how using multiple biotic proxies and extensive training sets in transfer functions may overcome taphonomic problems.
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Chu, Zhuding, Liguang Sun, Yuhong Wang, Tao Huang, and Xin Zhou. "Depositional environment and climate changes during the Holocene in Grande Valley, Fildes Peninsula, King George Island, Antarctica." Antarctic Science 29, no. 6 (2017): 545–54. http://dx.doi.org/10.1017/s095410201700030x.
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AbstractA 9.24 m sediment core, GA-2, was collected on the coastal platform of Grande Valley, a relatively narrow and shallow fjord in Fildes Peninsula, King George Island, Antarctica. The sediment was formed between 6600 and 2000 cal. yr bp according to accelerator mass spectrometry (AMS) 14C dating of five bulk sediment samples. The comprehensive proxy indicators (grain size, loss on ignition at 550°C, magnetic susceptibility, elements) were analysed, and three separate depositional environments and an alternating climate change pattern were identified. Grande Valley experienced a warm marine environment between 6600 and 5800 cal. yr bp, a minor cooling between 5800 and 4800 cal. yr bp, the transition from cool to warm during 4800–4400 cal. yr bp, a mid-Holocene climatic optimum between 4400 and 2700 cal. yr bp, and the onset of the Neoglacial at 2700 cal. yr bp. This study reconstructed the environmental history of Grande Valley during the mid–late Holocene, provides the missing marine record of historical climate for the western coast of Fildes Peninsula and lays the foundation for further study of the climate and environment changes therein. Our finding that the sea level was c. 12 m a.m.s.l. at 2000 cal. yr bp allows for detailed reconstruction of Holocene sea level variations.
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Barhoumi, Chéïma, Marianne Vogel, Lucas Dugerdil, et al. "Holocene Fire Regime Changes in the Southern Lake Baikal Region Influenced by Climate-Vegetation-Anthropogenic Activity Interactions." Forests 12, no. 8 (2021): 978. http://dx.doi.org/10.3390/f12080978.
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Catastrophic fire years that have taken place during the last decade in Siberia, and more generally within the boreal forest, have been directly linked to global warming and had strong repercussions on boreal ecosystems and human populations. In this context the study of the past dynamics of these fires is essential for understanding their links with climate, vegetation and human activity changes on longer time scales than the last few decades. However, few studies on fire dynamics are available for Siberia, and none have been conducted for the entire Holocene period. This study presents the first fire history reconstruction of this area during the Holocene based on charcoals sequestered in sediments of two lakes located on the southern shore of Lake Baikal, in Siberia. The results show a similar trend in the two lakes, with high frequency and high peak magnitude during the Early Holocene and low magnitudes after 6500 cal. yr BP. This difference is interpreted as crown fires versus surface fires. According to pollen records (Dulikha, Vydrino, Ochkovoe) available near the studied lakes, a vegetation transition occurred at the same time. Picea obovata, which has a tree structure prone to crown fires, was dominant during the Early humid Holocene. After 6500 cal. yr BP, conditions were drier and Pinus sylvestris and Pinus sibirica became the dominant species; their tree structure favors surface fires. In addition to vegetation dynamics, the nearby pollen sequence from Dulikha has been used to provide quantitative estimates of past climate, indicating an Early to Middle Holocene climatic optimum between 8000 and 5000 cal. yr BP and an increase in temperatures at the end of the Holocene. These results have been compared to outputs from regional climate models for the Lake Baikal latitudes. Fire dynamics appear to have been more linked to the vegetation than climatic conditions. Over the past 1500 years, the greater presence of human populations has firstly resulted in an increase in the fire frequency, then in its maintenance and finally in its suppression, which may possibly have been due to very recent fire management, i.e., after ca 500 cal. BP.
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Ciais, P., J. R. Petit, J. Jouzel, et al. "Evidence for an early Holocene climatic optimum in the Antarctic deep ice-core record." Climate Dynamics 6, no. 3-4 (1992): 169–77. http://dx.doi.org/10.1007/bf00193529.
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Cremer, Holger, Martin Melles, and Bernd Wagner. "Holocene climate changes reflected in a diatom succession from Basaltsø, East Greenland." Canadian Journal of Botany 79, no. 6 (2001): 649–56. http://dx.doi.org/10.1139/b01-039.
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Information on Holocene lacustrine diatom records from Greenland is rare. Here, a complete Holocene diatom succession is described from a sediment core recovered from Basaltsø, an arctic lake on Geographical Society Ø, eastern Greenland. Based on radiocarbon measurements on plant material, the upper 2.42 m of the 9.85 m long sediment sequence represent the Holocene sedimentological record in this area from about 10 000 calibrated (cal.) years BP. The diatom assemblages in Basaltsø are dominated by only a few species. Four stratigraphic diatom zones could be distinguished. During the early Holocene, mainly Staurosira construens (Ehr.) Williams et Round, Nitzschia amphibia Grunow, and Pinnularia mesolepta (Ehr.) W. Smith were the dominant taxa. After this initial stage, between 9600 and 5000 cal. years BP, Staurosirella pinnata (Ehr.) Williams et Round was the most abundant diatom species. From 4500 to 500 cal. years BP, the diatom assemblage was characterized by the co-occurrence of several taxa, including S. construens. S. pinnata, Kolbesia suchlandtii (Hust.) Kingston, and Cyclotella sp. A (rossiitripartitacomensis complex) as the main contributors. Finally, from 500 cal. years BP, the diatom assemblage was clearly dominated by Cyclotella sp. A, Cyclotella pseudostelligera Hustedt, and Sellaphora spp. The Holocene relative frequencies of S. pinnata and S. construens clearly correlate with the total diatom valve concentration, the Betula and Salix pollen percentage in Basaltsø, and the oxygen isotope record from the Renland ice core. This suggests that S. pinnata and S. construens are temperature-sensitive species that responded on the general climatic development in eastern Greenland during the Holocene. The diatom record together with the pollen and geochemical data of Basaltsø indicate to the Holocene climatic optimum on Geographical Society Ø from ca. 9000 to 6500 cal. years BP.Key words: Arctic, Greenland, Holocene, diatoms, paleolimnology, environmental change.