| 1. |
- Comas-Bru, Laia, et al.
(författare)
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Evaluating model outputs using integrated global speleothem records of climate change since the last glacial
- 2019
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Ingår i: Climate of the Past. - : Copernicus GmbH. - 1814-9324 .- 1814-9332. ; 15:4, s. 1557-1579
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Tidskriftsartikel (refereegranskat)abstract
- Although quantitative isotope data from speleothems has been used to evaluate isotope-enabled model simulations, currently no consensus exists regarding the most appropriate methodology through which to achieve this. A number of modelling groups will be running isotope-enabled palaeoclimate simulations in the framework of the Coupled Model Intercomparison Project Phase 6, so it is timely to evaluate different approaches to using the speleothem data for data-model comparisons. Here, we illustrate this using 456 globally distributed speleothem delta O-18 records from an updated version of the Speleothem Isotopes Synthesis and Analysis (SISAL) database and palaeoclimate simulations generated using the ECHAM5-wiso isotope-enabled atmospheric circulation model. We show that the SISAL records reproduce the first-order spatial patterns of isotopic variability in the modern day, strongly supporting the application of this dataset for evaluating model-derived isotope variability into the past. However, the discontinuous nature of many speleothem records complicates the process of procuring large numbers of records if data-model comparisons are made using the traditional approach of comparing anomalies between a control period and a given palaeoclimate experiment. To circumvent this issue, we illustrate techniques through which the absolute isotope values during any time period could be used for model evaluation. Specifically, we show that speleothem isotope records allow an assessment of a model's ability to simulate spatial isotopic trends. Our analyses provide a protocol for using speleothem isotope data for model evaluation, including screening the observations to take into account the impact of speleothem mineralogy on delta O-18 values, the optimum period for the modern observational baseline and the selection of an appropriate time window for creating means of the isotope data for palaeo-time-slices.
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| 2. |
- Atsawawaranunt, Kamolphat, et al.
(författare)
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The SISAL database : a global resource to document oxygen and carbon isotope records from speleothems
- 2018
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Ingår i: Earth System Science Data. - : Copernicus GmbH. - 1866-3508 .- 1866-3516. ; 10:3, s. 1687-1713
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Tidskriftsartikel (refereegranskat)abstract
- Stable isotope records from speleothems provide information on past climate changes, most particularly information that can be used to reconstruct past changes in precipitation and atmospheric circulation. These records are increasingly being used to provide "out-of-sample" evaluations of isotope-enabled climate models. SISAL (Speleothem Isotope Synthesis and Analysis) is an international working group of the Past Global Changes (PAGES) project. The working group aims to provide a comprehensive compilation of speleothem isotope records for climate reconstruction and model evaluation. The SISAL database contains data for individual speleothems, grouped by cave system. Stable isotopes of oxygen and carbon (delta O-18, delta C-13) measurements are referenced by distance from the top or bottom of the speleothem. Additional tables provide information on dating, including information on the dates used to construct the original age model and sufficient information to assess the quality of each data set and to erect a standardized chronology across different speleothems. The metadata table provides location information, information on the full range of measurements carried out on each speleothem and information on the cave system that is relevant to the interpretation of the records, as well as citations for both publications and archived data.
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| 3. |
- Bini, Monica, et al.
(författare)
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The 4.2 ka BP Event in the Mediterranean region : An overview
- 2019
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Ingår i: Climate of the Past. - : Copernicus GmbH. - 1814-9324 .- 1814-9332. ; 15:2, s. 555-577
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Tidskriftsartikel (refereegranskat)abstract
- The Mediterranean region and the Levant have returned some of the clearest evidence of a climatically dry period occurring around 4200 years ago. However, some regional evidence is controversial and contradictory, and issues remain regarding timing, progression, and regional articulation of this event. In this paper, we review the evidence from selected proxies (sea-surface temperature, precipitation, and temperature reconstructed from pollen, δ 18 O on speleothems, and δ 18 O on lacustrine carbonate) over the Mediterranean Basin to infer possible regional climate patterns during the interval between 4.3 and 3.8 ka. The values and limitations of these proxies are discussed, and their potential for furnishing information on seasonality is also explored. Despite the chronological uncertainties, which are the main limitations for disentangling details of the climatic conditions, the data suggest that winter over the Mediterranean involved drier conditions, in addition to already dry summers. However, some exceptions to this prevail - where wetter conditions seem to have persisted - suggesting regional heterogeneity in climate patterns. Temperature data, even if sparse, also suggest a cooling anomaly, even if this is not uniform. The most common paradigm to interpret the precipitation regime in the Mediterranean - a North Atlantic Oscillation-like pattern - is not completely satisfactory to interpret the selected data.
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| 4. |
- Bonnier, Anton, et al.
(författare)
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Climate variability and landscape dynamics in the Late Hellenistic and Roman north-eastern Peloponnese
- 2020
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Ingår i: Antiquity. - : CAMBRIDGE UNIV PRESS. - 0003-598X .- 1745-1744. ; 94:378, s. 1482-1500
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Tidskriftsartikel (refereegranskat)abstract
- Research on ancient Greek rural settlement and agricultural economies often emphasises political agency as a driving force behind landscape change, with comparatively less attention directed to the potential effects of climate. This study analyses climate variability and the spatial configuration of land use in the north-eastern Peloponnese during the Late Hellenistic and Roman (c. 150 BC-AD 300) periods. A synthesis of archaeological field survey data combined with new palaeoclimatological data provides novel insight into how changing climate influenced land use. The authors argue that although climatic variability alone did not drive socio-economic change, drying conditions may have influenced the relocation of agricultural production.
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| 5. |
- Bonnier, Anton, et al.
(författare)
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Examining Land-Use through GIS-Based Kernel Density Estimation : A Re-Evaluation of Legacy Data from the Berbati-Limnes Survey
- 2019
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Ingår i: Journal of field archaeology. - : ROUTLEDGE JOURNALS, TAYLOR & FRANCIS LTD. - 0093-4690 .- 2042-4582. ; 44:2, s. 70-83
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Tidskriftsartikel (refereegranskat)abstract
- The use of archaeological survey data for evaluation of landscape dynamics has commonly been concerned with the distribution of settlements and changes in number of recorded sites over time. Here we present a new quantitative approach to survey-based legacy data, which allows further assessments of the spatial configuration of possible land-use areas. Utilizing data from an intensive archaeological survey in the Berbati-Limnes area, Greece, we demonstrate how GIS-based kernel density estimations (KDE) can be used to produce cluster-based density surfaces that may be linked to past land-use strategies. By relating density surfaces to elevation and slope, it is also possible to quantify shifts in the use of specific environments on a regional scale, allowing us to model and visualize land-use dynamics over time. In this respect, the approach provides more multifaceted information to be drawn from archaeological legacy data, providing an extended platform for research on human-environment interactions.
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| 6. |
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| 7. |
- Dibble, Flint, et al.
(författare)
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Socioenvironmental change as a process : Changing foodways as adaptation to climate change in South Greece from the Late Bronze Age to the Early Iron Age
- 2021
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Ingår i: Quaternary International. - : Elsevier. - 1040-6182 .- 1873-4553. ; 597, s. 50-62
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Tidskriftsartikel (refereegranskat)abstract
- Recent interest in modern climate change has stimulated extensive scientific study into past societal responses to climate variability. However, examining climate change and society as a historical narrative drawing upon politics, economics, and settlement patterns does not provide a direct link between climate and society. Given that most inhabitants of the premodern world engaged in agriculture and/or pastoralism, examining chronological correlations between climate and foodways, not as a historical narrative but as a longterm socioenvironmental process, has the potential to identify direct societal adaptations to a changing environment. From South Greece there is evidence for drier conditions at the end of the Late Bronze Age. Is the disappearance of writing, art, and many known settlements at the end of the Bronze Age an example of collapse in the face of inability to adapt to climate change? This is a difficult question to answer given the coarse resolution of many of our archaeological and climatic datasets. Settlement faunal records suggest that food production systems became increasingly homogenous in Late Bronze Age Greece, potentially due to an elite control over various production systems that promoted intensification of certain products. However, in the first millennium B.C.E., animal husbandry, specifically, and food production systems, more broadly, became more heterogenous, and a proportional increase in goats in areas with less rainfall was likely an adaptive response to the drier climate. This paper examines the adaptive relationship between foodways and climate and argues for a process driven approach when explaining social responses to ancient climate change.
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| 8. |
- Finné, Martin, et al.
(författare)
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Can XRF scanning of speleothems be used as a non-destructive method to identify paleoflood events in caves?
- 2015
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Ingår i: International Journal of Speleology. - 0392-6672 .- 1827-806X. ; 44:1, s. 17-23
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Tidskriftsartikel (refereegranskat)abstract
- We have developed a novel, quick and non-destructive method for tracing flood events in caves through the analysis of a stalagmite thick section with an XRF core scanner. The analyzed stalagmite has multiple horizons of fine sediments from past flood events intercalated with areas of cleaner calcite. Flood events detected from the elemental XRF core scanning data show good agreement with the position of flood horizons identified in petrographic thin sections. The geochemical composition of the individual flood layers shows that in certain cases the clay horizons had a distinct geochemical fingerprint suggesting that it may be possible to distinguish individual flood layers based on their geochemistry. This presents the possibility for using flood events as marker horizons to chronologically tie different speleothems in a cave to each other.
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| 9. |
- Finné, Martin, et al.
(författare)
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Climate in the eastern Mediterranean, and adjacent regions, during the past 6000 years - A review
- 2011
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Ingår i: Journal of Archaeological Science. - : Elsevier BV. - 0305-4403 .- 1095-9238. ; 38:12, s. 3153-3173
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Forskningsöversikt (refereegranskat)abstract
- The eastern Mediterranean, with its long archaeological and historical records, provides a unique opportunity to study human responses to climate variability. We review paleoclimate data and reconstructions from the region with a focus on the last 6000 years. We aim to provide an up-to-date source of information on climate variability and to outline present limitations and future opportunities. The review work is threefold: (1) literature review, (2) spatial and temporal analysis of proxy records, and (3) statistical estimation of uncertainties in present paleoclimate reconstructions (temperature, C). On a regional scale the review reveals a wetter situation from 6000 to 5400 yrs BP (note: all ages in this paper are in calibrated years before present (i.e. before 1950), abbreviated yrs BP, unless otherwise stated). This is followed by a less wet period leading up to one of fully-developed aridity from c. 4600 yrs BP. There is a need for more high-resolution paleoclimate records, in order to (i) better understand regional patterns and trends versus local climate variability and to (ii) fill the gap of data from some regions, such as the Near East, Greece and Egypt. Further, we evaluate the regional occurrence of a proposed widespread climate event at 4200 yrs BP. This proposed climate anomaly has been used to explain profound changes in human societies at different locations in the region around this time. We suggest that although aridity was widespread around 4200 yrs BP in the eastern Mediterranean region, there is not enough evidence to support the notion of a climate event with rapidly drying conditions in this region.
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| 10. |
- Finné, Martin, 1981-
(författare)
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Climate in the eastern Mediterranean during the Holocene and beyond – A Peloponnesian perspective
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis contributes increased knowledge about climate variability during the late Quaternary in the eastern Mediterranean. Results from a paleoclimate review reveal that regional wetter conditions from 6000 to 5400 years BP were replaced by a less wet period from 5400 to 4600 years BP and to fully arid conditions around 4600 years BP. The data available, however, show that there is not enough evidence to support the notion of a widespread climate event with rapidly drying conditions in the region around 4200 years ago. The review further highlights the lack of paleoclimate data from the archaeologically rich Peloponnese Peninsula. This gap is addressed in this thesis by the provision of new paleoclimate records from the Peloponnese. One stalagmite from Kapsia Cave and two stalagmites from Glyfada Cave were dated and analyzed for stable oxygen (δ18O) and carbon (δ13C) isotopes. The Glyfada record covers a period from ~78 ka to ~37 ka and shows that the climate in this region responded rapidly to changes in temperatures over Greenland. During Greenland stadial (interstadial) conditions colder (warmer) and drier (wetter) conditions are reflected by depleted (enriched) δ13C-values in the speleothems. The Kapsia record covers a period from ~2900 to ~1100 years BP. A comparison between the modern stalagmite top isotopes and meteorological data shows that a main control on stalagmite δ18O is wet season precipitation amount. The δ18O record from Kapsia indicates cyclical humidity changes of close to 500 years, with rapid shifts toward wetter conditions followed by slowly developing aridity. Superimposed on this signal is a centennial signal of precipitation variability. A second speleothem from Kapsia with multiple horizons of fine sediments from past flood events intercalated with the calcite is used to develop a new, quick and non-destructive method for tracing flood events in speleothems by analyzing a thick section with an XRF core scanner.
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