Evaluating human responses to ENSO driven climate change during the Holocene in northwest Australia through macrobotanical analyses

The Holocene ◽  
2020 ◽  
Vol 30 (12) ◽  
pp. 1728-1740 ◽  
Author(s):  
India Ella Dilkes-Hall ◽  
Jane Balme ◽  
Sue O’Connor ◽  
Emilie Dotte-Sarout

The Holocene is recognised as a period through which a number of climatic fluctuations and environmental stresses occur—associated with intensifying El Niño–Southern Oscillation (ENSO) climatic conditions from c. 5000 years—contemporaneous with technological and social changes in Australian Aboriginal lifeways. In the Kimberley region of northwest Western Australia, human responses to ENSO driven climate change are most evident archaeologically in technological transformations observed in lithic records, with little research on changes in plant use during this time. Using nine archaeological sites across the Kimberley, this paper synthesises previously published macrobotanical data (Carpenter’s Gap 1, Moonggaroonggoo, Mount Behn, and Riwi), reports unpublished data (Brooking Gorge 1, Djuru, and Wandjina rockshelter), and presents results of sites reanalysed for this study (Widgingarri Shelters 1 and 2) to develop a picture of localised and regional patterns of plant use during the Holocene. We conclude that food plants associated with monsoon rainforest environments dominate both mid- and late Holocene macrobotanical records and, although monsoon rainforest likely retreated to some extent because of decreased precipitation during the late Holocene, no human responses associated with ENSO driven climate change occurred in relation to human uses of plants.

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Hendri Irwandi ◽  
Mohammad Syamsu Rosid ◽  
Terry Mart

AbstractThis research quantitatively and qualitatively analyzes the factors responsible for the water level variations in Lake Toba, North Sumatra Province, Indonesia. According to several studies carried out from 1993 to 2020, changes in the water level were associated with climate variability, climate change, and human activities. Furthermore, these studies stated that reduced rainfall during the rainy season due to the El Niño Southern Oscillation (ENSO) and the continuous increase in the maximum and average temperatures were some of the effects of climate change in the Lake Toba catchment area. Additionally, human interventions such as industrial activities, population growth, and damage to the surrounding environment of the Lake Toba watershed had significant impacts in terms of decreasing the water level. However, these studies were unable to determine the factor that had the most significant effect, although studies on other lakes worldwide have shown these factors are the main causes of fluctuations or decreases in water levels. A simulation study of Lake Toba's water balance showed the possibility of having a water surplus until the mid-twenty-first century. The input discharge was predicted to be greater than the output; therefore, Lake Toba could be optimized without affecting the future water level. However, the climate projections depicted a different situation, with scenarios predicting the possibility of extreme climate anomalies, demonstrating drier climatic conditions in the future. This review concludes that it is necessary to conduct an in-depth, comprehensive, and systematic study to identify the most dominant factor among the three that is causing the decrease in the Lake Toba water level and to describe the future projected water level.


2020 ◽  
Author(s):  
Sabrina Prochazka ◽  
Marta Luciani ◽  
Christopher Lüthgens

<p>The arid regions of the world occupy 46% of the total surface area, providing a habitat for 3 billion people. More than 630 million people are directly affected by desertification. Extreme events like droughts and flash floods increase the pressure on plants, animals and above all, humans and their settlements. In the context of a climate change with such far-reaching consequences, historical oases settlements stand out as best practice examples, because their water supply systems must have been adapted to the changing climate during the Holocene to guarantee the viability of the oases and their inhabitants. I will focus on the ancient oasis Qurayyah, located in the northwest of the Arabian Peninsula, a unique example in this context. Recent research has proven that, lacking a groundwater spring, the formation of a permanent settlement in Qurayyah was made possible mainly by surface-water harvesting, with local fracture springs potentially only providing drinking water. First numerical dating results for the water harvesting system from optically stimulated luminescence (OSL) dating of quartz confirm that the system was erected in a period characterized by changing climatic conditions from the Holocene climate optimum to the recent arid phase. This study aims to determine parameters and chronology of this sustainable irrigation system and intends to learn and understand how ancient settlers accomplished the construction of such a highly developed water supply system. To reach this research aim the irrigation system was reconstructed using field mapping and remote sensing techniques. It was shown that the reconstructed irrigation system worked as a flood irrigation system. Dams and channels were built to maximize the flooded area and at the same time to prevent catastrophic flooding under high discharge conditions. Contemporaneous historical irrigation systems in comparable size and complexity are known from Mesopotamia or Egypt. In addition to the system’s reconstruction, a new reverse engineering approach based on palaeobotany was developed for Qurayyah to reconstruct the climate conditions during the time of its operation. Compared to today’s precipitation of 32 mm per year in the research area, our results imply that the irrigation system was constructed in a time of significant climate change, because significantly higher amounts of precipitation would have been necessary to enable the cultivation of olive trees (reference plant for the reverse engineering approach), with a sufficient amount of water.</p>


2017 ◽  
Vol 34 (1) ◽  
pp. 61-69 ◽  
Author(s):  
Abdelfattah A. Zalat ◽  
Leszek Marks ◽  
Fabian Welc ◽  
Alaa Salem ◽  
Jerzy Nitychoruk ◽  
...  

Abstract This study evaluates changes in the environmental and climatic conditions in the Faiyum Oasis during the Holocene based on diatom analyses of the sediment FA-1 core from the southern seashore of the Qarun Lake. The studied FA-1 core was 26 m long and covered the time span ca. 9.000 cal. yrs BP. Diatom taxa were abundant and moderately to well-preserved throughout the core sediments. Planktonic taxa were most abundant than the benthic and epiphytic forms, which were very rare and sparsely distributed. The most dominant planktonic genera were Aulacoseira and Stephanodiscus followed by frequently distribution of Cyclostephanos and Cyclotella species. The stratigraphic distribution patterns of the recorded diatoms through the Holocene sediments explained five ecological diatom groups. These groups represent distinctive environmental conditions, which were mainly related to climatic changes through the early and middle Holocene, in addition to anthropogenic activity during the late Holocene. Comparison of diatom assemblages in the studied sediment core suggests that considerable changes occurred in water level as well as salinity. There were several high stands of the freshwater lake level during humid, warmer-wet climatic phases marked by dominance of planktonic, oligohalobous and alkaliphilous diatoms alternated with lowering of the lake level and slight increases in salinity and alkalinity during warm arid conditions evident by prevalence of brackish water diatoms.


2021 ◽  
Vol 15 (8) ◽  
pp. 4073-4097
Author(s):  
Matt O'Regan ◽  
Thomas M. Cronin ◽  
Brendan Reilly ◽  
Aage Kristian Olsen Alstrup ◽  
Laura Gemery ◽  
...  

Abstract. The northern sector of the Greenland Ice Sheet is considered to be particularly susceptible to ice mass loss arising from increased glacier discharge in the coming decades. However, the past extent and dynamics of outlet glaciers in this region, and hence their vulnerability to climate change, are poorly documented. In the summer of 2019, the Swedish icebreaker Oden entered the previously unchartered waters of Sherard Osborn Fjord, where Ryder Glacier drains approximately 2 % of Greenland's ice sheet into the Lincoln Sea. Here we reconstruct the Holocene dynamics of Ryder Glacier and its ice tongue by combining radiocarbon dating with sedimentary facies analyses along a 45 km transect of marine sediment cores collected between the modern ice tongue margin and the mouth of the fjord. The results illustrate that Ryder Glacier retreated from a grounded position at the fjord mouth during the Early Holocene (> 10.7±0.4 ka cal BP) and receded more than 120 km to the end of Sherard Osborn Fjord by the Middle Holocene (6.3±0.3 ka cal BP), likely becoming completely land-based. A re-advance of Ryder Glacier occurred in the Late Holocene, becoming marine-based around 3.9±0.4 ka cal BP. An ice tongue, similar in extent to its current position was established in the Late Holocene (between 3.6±0.4 and 2.9±0.4 ka cal BP) and extended to its maximum historical position near the fjord mouth around 0.9±0.3 ka cal BP. Laminated, clast-poor sediments were deposited during the entire retreat and regrowth phases, suggesting the persistence of an ice tongue that only collapsed when the glacier retreated behind a prominent topographic high at the landward end of the fjord. Sherard Osborn Fjord narrows inland, is constrained by steep-sided cliffs, contains a number of bathymetric pinning points that also shield the modern ice tongue and grounding zone from warm Atlantic waters, and has a shallowing inland sub-ice topography. These features are conducive to glacier stability and can explain the persistence of Ryder's ice tongue while the glacier remained marine-based. However, the physiography of the fjord did not halt the dramatic retreat of Ryder Glacier under the relatively mild changes in climate forcing during the Holocene. Presently, Ryder Glacier is grounded more than 40 km seaward of its inferred position during the Middle Holocene, highlighting the potential for substantial retreat in response to ongoing climate change.


Author(s):  
Andrew G. Fountain ◽  
W. Berry Lyons

The view of climate change during the Pleistocene and the Holocene was very much different a mere decade ago. With the collection and detailed analyses of ice core records from both Greenland and Antarctica in the early and mid-1990s, respectively, the collective view of climate variability during this time period has changed dramatically. During the Pleistocene, at least as far back as 450,000 years b.p., abrupt and severe temperature fluctuations were a regular occurrence rather than the exception (Mayewski et al. 1996, 1998; Petit et al. 1999). During the Pleistocene, these rapid and large climatic fluctuations, initially identified in the ice core records, have been verified in both marine and lacustrine sediments as well (Bond et al. 1993; Grimm et al. 1993), suggesting large-scale (hemispheric to global) climate restructuring over very short periods of time (Mayewski et al. 1997). Similar types of climatic fluctuations, but with smaller amplitudes, have also occurred during the Holocene (O’Brien et al. 1995; Bond et al. 1997; Arz et al. 2001). What were the biological responses to these changes in temperature, precipitation, and atmospheric chemistry? We must answer this question if we are to understand the century- to millennial-scale influence of climate on the structure and function of ecosystems. Because the polar regions are thought to be amplifiers of global climate change, these regions are ideal for investigating the response of ecological systems to, what in temperate regions might be considered, small-scale climatic variation. Our knowledge of past climatic variations in Antarctica comes from different types of proxy records, including ice core, geologic, and marine (Lyons et al. 1997). It is clear, however, that coastal Antarctica may respond to oceanic, atmospheric, and ice sheet–based climatic “drivers,” and therefore ice-free regions, such as the Mc- Murdo Dry Valleys, may respond to climate change in a much more complex manner than previously thought (R. Poreda, unpubl. data 2001). Since the initiation of the McMurdo Dry Valleys Long-Term Ecological Research program (MCM) in 1993, there has been a keen interest not only in the dynamics of the present day ecosystem, but also in the legacies produced via past climatic variation on the ecosystem. In this chapter we examine the current structure and function of the dry valleys ecosystem from the perspective of our work centered in Taylor Valley.


2016 ◽  
Vol 12 (2) ◽  
pp. 415-427 ◽  
Author(s):  
Enlou Zhang ◽  
Yongbo Wang ◽  
Weiwei Sun ◽  
Ji Shen

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.


2015 ◽  
Vol 81 ◽  
pp. 343-359 ◽  
Author(s):  
Nicholas Sutton ◽  
Glenn Summerhayes ◽  
Anne Ford

Over 40 years of archaeological investigations along the south coast of Papua New Guinea has identified a rapid succession of cultural changes during the late Holocene. The so-called ‘Papuan Hiccup’ (c. 1200–800 cal bp) is a poorly understood period of socio-economic upheaval along the coast, identified mainly from changes in archaeological ceramic styles and settlement patterns. During this period, the region-wide Early Papuan Pottery (EPP) tradition diverges into separate, localised ceramic sequences that have generic associations with local ethnographic wares. A correspondence between the timing of the Papuan Hiccup and a period of peak El Niño-Southern Oscillation (ENSO) activity implies a link between cultural and climate change. This paper explores this relationship further by examining changes in interaction networks along the south coast of Papua New Guinea, specifically focusing on chert artefacts. Chemical characterisation (portable X-Ray Fluorescence; pXRF) and technological analysis are used to map changes in lithic technology over time, including access to raw materials and technological organisation, at the site of Taurama, a prehistoric coastal village site that was occupied both prior to and after the Papuan Hiccup. Although the sample sizes are small and the interpretations necessarily circumscribed, it is argued that changes in the number of chert sources being exploited and in the intensity of core reduction at Taurama may be related to climate change in the region.


Author(s):  
П.С. Белянин ◽  
Н.И. Белянина

На основе палинологических данных, восстановлена история развития природной среды аккумулятивной равнины в кутовой части Уссурийского залива за последние 5350 кал. л. Определены особенности структуры растительного покрова в завершающую фазу оптимума голоцена, а также при разнонаправленных климатических флуктуациях позднего голоцена. В завершающую фазу оптимума голоцена широколиственные растения в горном обрамлении были распространены более широко, чем в настоящее время. На аккумулятивной равнине преобладали мелколиственные растительные сообщества с доминированием березы обыкновенной, гибридных берез и ольхи. Похолодание, начавшееся в конце среднего и продолжившееся в начале позднего голоцена, привело к сокращению в растительности широколиственных растений и более широкому распространению мелколиственных. В конце позднего голоцена в кутовой части Уссурийского залива сложились природные условия, обусловившие формирование современной структуры растительности. Based on the palynological data, the history of vegetation on the accumulative plain in the inner part of the Ussuri Bay was reconstructed. Features of the structure of the vegetation cover during the final phase of the Holocene optimum and at multidirectional climatic fluctuations in the Late Holocene were identified. Broad-leaf plants in the final phase of the Holocene were more widely-spread on the surrounding mountain than at present. On the accumulative plains grassy meadows with small-leaf plant communities dominated. Deterioration of natural conditions during the transition to the Late Holocene caused a decrease in vegetation of broad- leaved plants and in an increase in the role of small-plants. At the end of the Late Holocene natural conditions developed in the inner part of the Ussuri Bay, that conditioned the formation of the modern structure of vegetation.


2015 ◽  
Vol 11 (5) ◽  
pp. 4751-4786
Author(s):  
E. Zhang ◽  
Y. Wang ◽  
W. Sun ◽  
J. Shen

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.


2019 ◽  
Vol 92 (1) ◽  
pp. 109-132 ◽  
Author(s):  
Louise Purdue ◽  
Julien Charbonnier ◽  
Emmanuelle Régagnon ◽  
Carine Calastrenc ◽  
Thomas Sagory ◽  
...  

AbstractOases are subject to decreasing resources and changing human activities. Fully aware of their rich heritage, the United Arab Emirates (UAE) have undertaken work to preserve and revitalize these oases. However, there is a clear lack of understanding of the dynamic links between climate change, hydraulic and agricultural management, and socioeconomic activities. To clarify these links, our team conducted a systematic geoarchaeological, geophysical, spatial, and chronological study of the Masafi oasis, UAE. Results indicate the existence of a natural humid area as early as the late Pleistocene (~18 cal ka BP). These conditions persist during the early-mid Holocene with drainage activation and soil development (~12–6.3 ka). During the late Holocene, after the emergence of the “artificial” oasis around ~3250 cal yr BP, cycles of intense management suggesting water availability (~3250–2380 cal yr BP; 550 cal yr BP) alternate with episodes of fluvial detritism (~2380–1870 cal yr BP; >550 cal yr BP) and scattered evidence of farming activities with complex hydroclimatic signatures (~2300–550 cal yr BP). These results, together with regional environmental data, indicate that water and soil resources were available and exploited strategically throughout the Holocene despite adverse climatic conditions, and the oasis of Masafi could have acted as a desertrefugium.


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