The Holocene

Centennial-timescale variability of the Southern Hemisphere Westerly wind belt (SHW) is poorly documented, mainly due to a paucity of long, high-resolution climate records from the Southern Hemisphere. Moreover, the role played by the Southern Annular Mode (SAM), El Niño Southern Oscillation (ENSO) and solar variability in controlling the SHW is not well understood. We present a 7000-year record of grain size end-member modelling and C/N from Lake Lanalhue at 38°S in central Chile as a reconstruction of variations in precipitation and the position of the northern margin of the SHW. Centennial-scale drier/wetter conditions in central Chile were coeval not only with drier/wetter and cooler/warmer conditions in southern Chile, but also with more/less extensive sea ice and cooler/warmer conditions in the Ross Sea, stronger/weaker winds in the Amundsen Sea, and equatorward/poleward shifted SHW in the southwestern Atlantic Ocean. Taken together this indicates centennial-scale variations resembling positive/negative phases of the Southern Annular Mode (SAM⁺/SAM^–). Drier/wetter conditions were also related to more/less El Niño conditions. Therefore, we suggest that SHW variability in central Chile at a centennial-timescale was related to the ENSO-SAM phasing, i.e. El Niño/SAM⁺ during drier periods and La Niña/SAM^– during wetter periods, and ultimately controlled by solar variability, with increased/decreased insolation forcing shifts towards a SAM⁺/SAM^–-like state.

In Central Europe, burning has been widely practiced as part of the slash-and-burn cultivation since the Neolithic Age and was an essential component in forming the recent landscape. To improve our knowledge on historical fire events, we evaluated charcoals in the soil of 44 semi-dry and 38 wet grasslands in Southern Germany. With 92%, most locations contained charcoal, proving fire as a common tool applied in both grassland types. Charcoals of 57 locations were identified. The tree composition was then used to classify the locations at the time burning took place into open conditions, early succession and late succession. Around two-thirds of the sites showed open conditions or early succession and had been already part of the agricultural landscape at the time of fire. Correlations of additional parameters to the charcoal content were rather subtle. Semi-dry grasslands with high charcoal contents tended to be steeper and exhibited more endangered plants. Wet meadows with high amounts of charcoal had low levels of nitrogen since a lot becomes airborne by fire and is not available in the long term. Radiocarbon dating showed that the history of burning was continuous for semi-dry grasslands from Modern times to the early Iron Age and for wet meadows almost continuous until the Bronze Age. These results revealed a frequent occurrence of fires and a long history of fire application in Southern Germanys agricultural landscape. Burning was an important tool regardless of the grassland type and period to ensure good harvests.

The Western Siberian peatlands rank among the largest in the Northern Hemisphere. This study investigates peatland development and palaeohydrological changes of the Mukhrino mire during the Holocene focussing on climatic, regional and local factors. The multiproxy and multi-core approach reveals spatial variability driven by topography and sedimentary conditions. Our study integrates testate amoebae, plant macrofossils, peat geochemical and biomarkers to provide insights into past vegetation and environmental conditions. Peat accumulation in Mukhrino mire began in the early Holocene, with regional vegetation influenced by climatic and soil factors. Forest cover has been present since the Early Holocene. Birch and pine dominated in the drained areas and episodic regional presence of Tilia and Ulmus indicated warmer intervals. Since ~8800 cal yr BP, Mukhrino mire transitioned to an oligotrophic/ombrotrophic state dominated by Sphagnum fuscum. A key focus of this study is the dynamics of peatland surface wetness over millennia. Proxy-specific responses revealed both short-term variability (via testate amoebae) and long-term climatic trends (via plant macrofossils). Local dry phases (~6500–5700/4700 and 2200–1800 cal yr BP) resulted in partial mire afforestation, while wetter periods (~5700/4700–2500 cal yr BP) facilitated the restoration of its current state. Comparisons with prior studies identified two wet and four dry zones, with synchronised wetness trends across cores despite localised variations in peat accumulation rates. A pronounced local wet phase (~6700–6800 cal yr BP) corresponds with a marker layer from nearby Lake Svetlenkoye sediments (~8000–6700 cal yr BP), attributed to Ob River palaeo-floods. This evidence supports the presence of regionally wet environmental conditions during this period.

The study of paleomiddens in desert environments is crucial for understanding past ecological and environmental dynamics, as these sites offer unique opportunities to preserve ancient biological materials. Rodent middens have contributed significantly to the understanding of biotic responses to late Quaternary environmental changes in arid ecosystems like the Atacama Desert. This region has been home to human populations since ancient times. Paleoparasitology plays an essential role in reconstructing ancient parasite relationships. This study examines the gastrointestinal parasite diversity in rodent middens from the central Atacama Desert, spanning from 2400 cal years BP to modern times, with a focus on exploring the connections between parasites, human activity, and environmental changes. Thirteen parasite species or morphotypes from Nematoda and Coccidia were identified, including two with zoonotic potential, indicating possible exposure risks to ancient populations. Using a combination of ancient DNA (aDNA) analysis, fecal morphology, and specific parasites, two rodent species (Cricetidae and Octodontidae) were identified. Parasite richness and the number of eggs and oocysts fluctuated over time, likely in response to environmental shifts and associated ecological dynamics. This research integrates traditional techniques with aDNA analysis, providing new insights into the health challenges faced by ancient populations and highlighting the need for continued research in this field. It also offers valuable data on how both ancient and modern organisms coped with health threats in a harsh and fluctuating environment. The findings underscore the potential of paleoparasitology to reveal the complexities of ancient parasite dynamics and environmental conditions, paving the way for future interdisciplinary studies.

The Sahara and Arabian deserts are traditionally thought to be the source of settled dust in the Middle East. Although there have been suggestions of evidence for contributions from local sources, isotopic and clay mineral data have not yet confirmed this. The current study adds the neodymium and strontium isotopic signals as well as the mineralogical composition of the clay fraction to earlier investigations of trapped Holocene eolian sediments in archeological structures carried out in the northern Negev, Israel, and the Petra region, Jordan. Identifying the Holocene and present-day dust source areas and weighing the relative importance of local and remote resources are the objectives of the current study. Illite-smectite (IS) predominates the clay fraction in the Negev, and kaolinite (Ka) in Petra. Clay minerals of both regions form a continuous line of two populations between dust end members of about 75% IS in the Negev and about 75% Ka in Petra. Petra and the Negev have εNd values of −8.8 to −14.1 and −5.1 to −8.6 and ⁸⁷Sr/⁸⁶Sr ratios between 0.7082 and 0.7119 and 0.7085 and 0.7134, respectively. The ⁸⁷Sr/⁸⁶Sr ranges in the Petra and Negev regions are rather similar, indicating that carbonate rocks from both local and remote sources have had a significant role. It may be inferred that the distinctive εNd values of the Petra eolian sediments must be generated from the local Paleozoic sandstone, even in the absence of information on the isotopic composition of any of the local rocks. Dust from the semi-distant Petra region, the remote Mesopotamia source area, and local sources all have an impact on Negev isotopic signals, but not the Sahara. This is because the significant contribution of coarse-grain local materials masks fine-grain materials from distant sources.

We evaluate area change of small cirque glaciers in the Argentine sector of the Fuegian Andes, from moraines mapping, aerial photography (1970 and 1988), Landsat 5 (2000 and 2010), Landsat 8 (2015) and Sentinel (2020) satellite imagery. Changes in glacier area were compared to temperature and precipitation data from ERA5 over the period 1950–2020. Our results show a strong relation between glacial retreat and changes in air temperature. Collectively, the glaciers shrank by 70% from positions achieved during the Little Ice Age (~1870). Half of this glacial retreat (total glacier area loss equaled 3.8 km²) occurred after 1960–1970 when an increase of approximately 1°C in the mean annual temperature was recorded in the area. We observe a rapid increase in the rate of area loss and glacial retreat speed after 2015, with average values of 0.010 km² yr⁻¹ and 30 m/year, respectively, in concert with a rapid rise of observed air temperature (approximately 0.7°C). The intensification of the Southern Westerlies Winds (SWW) at this latitude, related to the positive trend in the Southern Annular Mode (SAM), produced an increase in temperature and decrease in precipitation in this sector which has induced a continuous and rapid glacial retreat since almost 1970.

Knowledge of deglacial history in high-altitude environments of the northern Neotropics remains limited, because most research has been focussed on lower elevations. This study presents a palaeoecological reconstruction of vegetation dynamics during the Early to Middle Holocene from a high-elevation peatland (3770 m asl) on Cofre de Perote volcano, located at the eastern end of the Trans-Mexican Volcanic Belt. A sedimentary sequence was analysed through palynological analyses, supported by charcoal, magnetic susceptibility, and titanium data. The pollen record, spanning 10.3–4.9 cal kyr BP, is divided into four pollen zones: (i) Between 10.3 and 10 cal kyr BP, low pollen values indicate poor preservation and periglacial conditions; (ii) From 10 to 9.5 cal kyr BP, pollen of herbaceous taxa related to pine forest and alpine grassland suggest early vegetation colonisation near 3700 m asl; (iii) Between ~9.5 and 7.6 cal kyr BP, pollen assemblages suggests alpine grassland development near the coring site, while high Cyperaceae and Isoëtes values around 8 cal kyr BP suggest peatland development; (iv) From ~7.6 to 4.9 cal kyr BP, increased Pinus and decreased herbaceous pollen could imply pine forest establishment at similar to modern elevations. These findings, supported by previous records, suggest that Early Holocene forests at Cofre de Perote were more stable and reached higher elevations than those further inland. Additionally, considering long-distance transport of wind-driven taxa is crucial for interpreting pollen assemblages of high altitudes locations following deglaciation. The presence of Picea pollen reflects a past vegetation community without modern analogue and indicates the volcano’s role as a microrefugia during the Early Holocene.

Understanding the relationship between historical climate change and famine is crucial for current disaster prevention and mitigation efforts. This study investigates how climatic variability and disasters influenced the timing, severity, and spatial patterns of famines in Jiangsu during the Ming dynasty (1368–1644 AD). Using semantic quantitative, spatiotemporal, and statistical analyses, a total of 1034 famine records were compiled, with an average of 3.73 counties affected per year. Famine events occurred most frequently in summer–autumn, particularly in May, June, and July, which together accounted for 71.7% of all occurrences. Based on both the scope and severity of events, a famine index defines four stages: low-frequency, high-frequency, occasional, and outbreak. These stages correspond to periodic cycles of 112, 58, and 19 years. Spatially, famine distribution exhibited significant variation, with southern Jiangsu experiencing more severe famine than the northern regions. At the county level, famine occurrences exhibited high spatial autocorrelation, forming a dual-core structure centered around Xuzhou and Nanjing. The driving mechanisms of famine were primarily associated with droughts, floods, locust plagues, and cold damage, with droughts being particularly impactful. These disasters were closely linked to solar activity and large-scale atmospheric circulations, which together shaped cold-dry periods marked by lower temperatures and reduced precipitation. Such climatic conditions were strongly associated with more frequent famine events, especially during the late Ming dynasty (after 1600 AD).

A multimillennial analysis of woodland ecosystems in the Leicestershire landscape (UK) shows significant anthropogenic stress over the last six millennia. We track these stresses using a combination of palynology and place-name evidence. We show a protracted period of deforestation from the Bronze Age (beginning ~4500 yr BP in Leicestershire), but the continuity of some woodland ecologies through to the present, with the managed re-establishment of some woodlands from the late Medieval period onward. Our overall analysis shows very considerable deforestation since prehistory, with an overall reduction in woodland cover from circa 60% - 70% to just 6%, and no pristine forest remaining. Nevertheless, the temperate mixed deciduous woodland shows considerable resilience to some of the more negative patterns of biosphere loss that characterize the Anthropocene and could be a beacon for restoration and conservation.

Existing discontinuous palynological records from coastal and river valley exposures, with varying quality of radiocarbon control, suggested that the regional Holocene climate in southern areas of the Russian Far East was characterized by as many as 10 fluctuations in temperature and/or precipitation. In this study, palynological data from Zerkalnoye Lake, located on the western coast of the Sea of Japan, indicate a gradual decline in temperature through the Middle and Late-Holocene with a Holocene thermal maximum between 8800 and 5500 cal yr BP. Three wetter than present intervals, marked by an increase in Pinus koraiensis, occurred c. 3600–3500 cal yr BP, 2340–2050 cal yr BP, and 1830–1800 cal yr BP. The Zerkalnoye record shows the dominance of Quercus-broadleaf forests during the Middle and Early Holocene, although Quercus shows a gradual decrease as climate cooled during this interval. Diatom analysis of the Zerkalnoye sediments documents that the site was a shallow bay or coastal lagoon until c. 3540 cal yr BP. After that time, a freshwater lake was established, which had variable marine influences probably caused by sea level changes following deglaciation. The diatom data indicate a cool water interval between 2900 and 2580 cal yr BP, also noted in other sites in the region. Changes in the basin’s depositional environment do not affect the palynological record, indicating such sites can provide reliable paleovegetational and paleoclimatic records. The discrepancies of the various regional paleoclimatic scenarios indicate the need for the further collection of continuous records from coastal to alpine zones in this region of northeastern Asia.