Global aridity synthesis for the last 60 000 years

Fuhrmann, Florian; Diensberg, Benedikt; Gong, Xun; Lohmann, Gerrit; Sirocko, Frank

doi:10.5194/cp-2019-108

Cited by 3 publications

(3 citation statements)

References 92 publications

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“…The second scenario implies that during the LGM the Nappe de Beauce ground water retained the characteristics of temperate climate ground waters and was mainly inherited from the preglacial period. This is in line with the combination of a very dry climate during the LGM (Fuhrmann et al, 2019) and permafrost behaving like a barrier for recharge by surface water (McEwen and de Marsily, 1991). In the meantime, permafrost would have restricted ground-water discharge to unfrozen "windows" along river valleys, and these discharges would have been somewhat compensated by an increase in ground-water volume due to water freezing (Woo, 2012), which in turn led to lateral flows from greater depths (Vidstrand, 2003).…”

supporting

confidence: 54%

Sand calcites as a key to Pleistocene periglacial landscapes

et al. 2020

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We tested the potential for sand calcites to serve as a novel paleoclimate archive by investigating their age and formation conditions. Fontainebleau sand calcites are Pleistocene in age (based on 14C and U-Th dating) and were primarily formed during glacial periods. δ13C values increase with the depth at which these sand calcites formed, consistent with open and closed CO2 systems. Interpretation of the δ18O-T relationship in sand calcites points primarily to their formation at a low temperature, around 2°C in shallow ground water and at about 9°C in deeper ground-water settings. Their occurrence, characteristics, and compositions suggest crystallization from paleo-ground waters in permafrost environments. Crystallization of sand calcites was triggered by degassing of cold carbonate-containing surface waters as they infiltrated warmer subsurface ground-water environments. We consider sand calcites to be important indicators of interactions between meteoric water and ground water in Pleistocene periglacial landscapes. Their disposition may point to specific features of periglacial landscapes, and their ages could permit an assessment of landscape incision rates. Large crystals and zoned spheroliths may, in fact, encapsulate continuous high-resolution records of continental glacial and periglacial paleoenvironments.

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supporting

confidence: 54%

Sand calcites as a key to Pleistocene periglacial landscapes

et al. 2020

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“…However, it has been inferred that greater insolation increased surface temperatures, leading to a decrease in effective moisture and consequently vegetation cover (Qiang et al, 2013). This interpretation is supported by the multi-proxy based reconstruction of aridity in the region proposed by Fuhrmann et al (2019). In accordance, studies in central and NE China evoked a period of extensive dune mobilisation (25-13 ka BP), transition from mobilisation to stabilisation ($13-8 ka BP) and substantial stabilisation ($8-4 ka BP) before a succession of multiple episodes of stabilisation/mobilisation (< $4 ka BP; Guo et al, 2018;Lu et al, 2011;Xu et al, 2015;Yang et al, 2012;Yu & Lai, 2012.…”

Section: Asiamentioning

confidence: 78%

Parabolic dune distribution, morphology and activity during the last 20 000 years: A global overview

Vimpere

2023

Earth Surf Processes Landf

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Parabolic dunes form and migrate in almost every climate and geographic zones of the world, ranging from the tropical coastlines to the arid continental deserts. Despite their extensive distribution and their importance within the aeolian sediment landscape, the understanding of their morphological development, activity and link with climates remains somewhat limited to local or regional scales. A good understanding of the present climate conditions under which parabolic dunes are formed and/or reactivated would be significantly helpful to constrain past climate models. Similarly, an improved knowledge of parabolic dunes behaviour during past climatic episodes would provide some valuable long‐term data to better predict their future activity. This review first aims at providing a non‐exhaustive global database on parabolic dune morphology and the present wind regimes with which they are associated. To do so, the morphology of 750 dunes distributed worldwide was first analysed using a high‐resolution global digital elevation model, suggesting an intrinsic relationship between the different measured morphoparameters. The analysis of the associated local wind regimes shows that parabolic dunes develop under strong unidirectional winds, which are more conspicuous in coastal than continental environments. Dunes of different ages are globally aligned with present prevailing winds, which suggests a prevalent control of long‐term global atmospheric circulation on dune orientations. Finally, this study explores the link between parabolic dune activity and climates over the past 20 000 years by reviewing ages from the literature and combining them with the ones compiled in the INQUA Dunes Atlas Chronologic Database. Overall, it appears that changes towards drier conditions have triggered dunes migration during both warm and cold periods of the Last Glacial Maximum, Holocene Climate Optimum, Roman Climate Optimum, Medieval Climate Optimum and Little Ice Age. The present day aeolian activity is predominantly linked with deteriorating environmental conditions caused by human disturbances.

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“…Both during the LGM and today, a strong gradient of total annual precipitation existed between lowlands and mountains in the Carpathian Basin (LGM: 540–1000 mm, present: 500–1300 mm; CCSM4.0). Data are inconsistent, suggesting both arid climate (Fuhrmann et al ., 2019; Obreht et al ., 2019) and humid/mild climate (Ludwig et al ., 2021) in the Carpathian Basin during the LGM. Precipitation data from the CCSM4.0 model indicate a humid climate.…”

Section: Environmental Conditions In the Carpathian Basin During The Lgmmentioning

confidence: 99%

Is there a massive glacial–Holocene flora continuity in Central Europe?

Molnár,

Demeter,

Biró

et al. 2023

Biological Reviews

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The prevailing paradigm about the Quaternary ecological and evolutionary history of Central European ecosystems is that they were repeatedly impoverished by regional extinctions of most species during the glacial periods, followed by massive recolonizations from southern and eastern refugia during interglacial periods. Recent literature partially contradicts this view and provides evidence to re‐evaluate this Postglacial Recolonization Hypothesis and develop an alternative one. We examined the long‐term history of the flora of the Carpathian (Pannonian) Basin by synthesising recent advances in ecological, phylogeographical, palaeoecological and palaeoclimatological research, and analysing the cold tolerance of the native flora of a test area (Hungary, the central part of the Carpathian Basin). We found that (1) many species have likely occurred there continuously since before the Last Glacial Maximum (LGM); (2) most of the present‐day native flora (1404 species, about 80%) can occur in climates as cold as or colder than the LGM (mean annual temperature ≤+3.5°C); and (3) grasslands and forests can be species‐rich under an LGM‐like cold climate. These arguments support an alternative hypothesis, which we call the Flora Continuity Hypothesis. It states that long‐term continuity of much of the flora in the Carpathian Basin is more plausible than regional extinctions during the LGM followed by massive postglacial recolonizations. The long‐term continuity of the region's flora may have fundamental implications not only for understanding local biogeography and ecology (e.g. the temporal scale of processes), but also for conservation strategies focusing on protecting ancient species‐rich ecosystems and local gene pools.

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Global aridity synthesis for the last 60 000 years

Cited by 3 publications

References 92 publications

Sand calcites as a key to Pleistocene periglacial landscapes

Sand calcites as a key to Pleistocene periglacial landscapes

Parabolic dune distribution, morphology and activity during the last 20 000 years: A global overview

Is there a massive glacial–Holocene flora continuity in Central Europe?

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