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The modern pattern of the Asian monsoon is thought to have formed around the Oligocene/Miocene transition and is generally attributed to Himalaya–Tibetan Plateau (H–TP) uplift. However, the timing of the ancient Asian monsoon over the TP and its response to astronomical forcing and TP uplift remains poorly known because of the paucity of well-dated high-resolution geological records from the TP interior. Here, we present a precession-scale cyclostratigraphic sedimentary section of 27.32 to 23.24 million years ago (Ma) during the late Oligocene epoch from the Nima Basin to show that the South Asian monsoon (SAM) had already advanced to the central TP (32°N) at least by 27.3 Ma, which is indicated by cyclic arid–humid fluctuations based on environmental magnetism proxies. A shift of lithology and astronomically orbital periods and amplified amplitude of proxy measurements as well as a hydroclimate transition around 25.8 Ma suggest that the SAM intensified at ~25.8 Ma and that the TP reached a paleoelevation threshold for enhancing the coupling between the uplifted plateau and the SAM. Orbital short eccentricity-paced precipitation variability is argued to be mainly driven by orbital eccentricity-modulated low-latitude summer insolation rather than glacial-interglacial Antarctic ice sheet fluctuations. The monsoon data from the TP interior provide key evidence to link the greatly enhanced tropical SAM at 25.8 Ma with TP uplift rather than global climate change and suggest that SAM’s northward expansion to the boreal subtropics was dominated by a combination of tectonic and astronomical forcing at multiple timescales in the late Oligocene epoch.

Climate changes had major impacts on the vegetation of East Asia during the last deglaciation. However, the rate and pattern of vegetation succession in response to large-scale climatic events during this interval are controversial. Here, we present well-dated decadal-resolution pollen records from annually laminated Maar Lake Xiaolongwan during the last deglaciation. The vegetation changes were rapid and near-synchronous with millennial-scale climatic events, including Greenland Stadial 2.1a (GS-2.1a), Greenland Interstadial 1 (GI-1), Greenland Stadial 1 (GS-1), and the early Holocene (EH). The vegetation responded in different ways to the different rates of climate change. Vegetation change was gradual [∼1 thousand years (kyr) response time] during the transition between GS-2.1a and GI-1, but it was faster (∼0.4 kyr response time) during the transitions between GI-1, GS-1, and the EH, resulting in different patterns of vegetation succession. Additionally, the amplitude and pattern of vegetation changes resembled those in the records of regional climate change based on long-chain n-alkanes δ13C and stalagmite δ18O, as well as in the mid-latitude Northern Hemisphere temperature record and the Greenland ice core δ18O record. Therefore, the rate and pattern of vegetation succession in the Changbai Mountain of Northeast Asia during the last deglaciation were sensitive to the characteristics of changes in the regional hydrothermal conditions and mid-latitude Northern Hemisphere temperature, which were linked to both high- and low-latitude atmospheric-oceanic dynamics. Overall, our findings reveal a close relationship between ecosystem succession and hydrothermal changes during these millennial-scale climatic events in East Asia during the last deglaciation.

Instrumental records indicate a close relationship between the El Nino-Southern Oscillation and the East Asian winter monsoon (EAWM) on interannual to decadal time scales. However, few studies have examined possible links between them on centennial/millennial time scales. In Northeast China, modern observations show that the immigration of temperate forest trees such as Pinus (pine) and Quercus (oak) into cold temperate boreal forest is sensitive to changes in winter temperature. Here we present a continuous high-resolution pollen record from Lake Moon in the central part of the Great Khingan Mountain Range, Northeast China. The record reveals increasing contents of Pinus and Quercus pollen after similar to 6.0 ka cal. BP, which may indicate a gradual weakening of the EAWM. It is broadly coupled with an increasing El Nino frequency since the middle Holocene, and we observe a statistically significant correlation between the percentages of Pinus and Quercus and a time series of El Nino events. On the centennial to millennial time scale, the results of wavelet analysis and band-pass filtering show that the occurrence and development of El Nino have also promoted a weaker EAWM after similar to 6.0 ka cal. BP, which is inversely correlated with the variation of the ca. 500-year cycle originated from changes in solar output. These results imply that the climate transition in the mid-Holocene is caused by the change of variations in solar activity and amplified by ocean circulation El Nino-Southern Oscillation to influence the East Asian Monsoon system, especially the EAWM, and finally change the vegetation in Great Khingan Mountain Range.

The ancient Loulan, situated on the west bank of Lake Lop Nur, Xinjiang, Northwest China, was an important town on the Silk Road connecting China to Europe. However, this once-prosperous kingdom has been a depopulated zone filled with wind-eroded mounds since approximately AD 500–600. A comprehensive understanding of the environmental setting of the flourishing Loulan civilization is a prerequisite for assessing environment–human interaction there. Here, we present our survey, chronology, and archaeobotany (the identification of plant remains) of vegetation use for architecture from eight ancient ruins of the Loulan kingdom to clarify the ecological landscape on the west bank of Lake Lop Nur and to assess paleoenvironmental conditions when the Loulan kingdom flourished. Our results suggest that Populus euphratica, tamarisk ( Tamarix Linn), and reed ( Phragmites Trin.) were most widely used as building materials in this period. Wood utilization for buildings depended entirely on indigenous vegetation rather than that of the mountains in the Loulan kingdom, even though the Loulan was a predominant transportation hub on the prosperous Silk Road. Our reconstruction indicates that the west bank of Lake Lop Nur was sufficiently wetter than present conditions to support riparian forest growth composed mainly of P. euphratica, tamarisk shrubs, and reed meadows, until approximately AD 500. These wetter conditions and flourishing civilization accompanied an increase in precipitation in arid central Asia. Conversely, combined evidence of both archeological and paleoclimatic records from the water sources of Lake Lop Nur and ancient oases suggest that abrupt decreased mountain precipitation could be considered a significant environmental factor in the decline of Loulan kingdom.

The Quaternary Chinese loess is one of the most continuous terrestrial sediments, and preserves excellent palaeoclimate records at different timescales. The conventional land-ocean palaeoclimatic comparison has been established by correlation between magnetic susceptibility of the Chinese loess and deep-sea δ 18 O records during the 1980s. However, such a correlation results in long-standing debates on the lock-in depth of the palaeomagnetic polarity boundaries in Chinese loess. In this study, the lock-in depth of palaeomagnetic signals for loess

The grass subfamily Pooideae originated in a temperate niche during the late Cretaceous; it is the largest Poaceae subfamily, consisting of almost 4,000 species, which are distributed worldwide. Pooideae responses to climate changes at different time scales, and different ecological zones are thus important in understanding Poaceae evolutionary processes and their relationship with climate change. In the study described in this article, we reconstructed Pooideae variability during the early Holocene, as inferred by a phytolith sequence from the Lower Yangtze in subtropical China. The phytolith assemblage was marked by three increases in Pooideae phytoliths, dated to ca 8.4–8.0, 7.8–7.6, and 7.4–7.2 ka BP (before present, 1950 AD), with each representing pronounced increases in Pooideae extent and distribution. All these increases were within age ranges that agreed well with the timing of weak Asian Monsoon events, at 8.2, 7.7, and 7.3 ka BP. The first Pooideae flourishing period in subtropical China was the most significant, lasting for approximately four centuries and being characterized by a double peak, which equated with an event at 8.2 ka. This suggested that cold and/or dry conditions—which occurred over a period of several hundred years and were linked to weakening of the Asian monsoon—probably caused Pooideae to flourish in the Lower Yangtze region. Comparison of two diagnostic trapezoid phytolith types—namely wavy and wavy narrow—which showed different changes between ca 8.4 and 8.0 ka BP, suggested that they responded differently to the climate change represented by the 8.2 ka event. Our phytolith records have provided not only new data clarifying the detailed Pooideae response to the 8.2 ka event but also a reliable index for past cold climates in subtropical China.

The eastern coastal zone of China is densely populated and widely recognized as a center of rice domestication, which has undergone dramatic sea-level fluctuation during the Holocene epoch. Hemudu culture is distributed mainly in the eastern coastal area and was once presumed as a mature agricultural economy based on rice, making it an ideal case for examining the remarkable human-environment interaction in the Lower Yangtze River. Though numerous studies have been conducted on the cultural evolution, ecological environment, and rice domestication of Hemudu culture, the impact of sea-level fluctuation on human settlement and food production remains controversial. In this study, we report high-resolution pollen, phytolith, and diatom records, and accurately measured elevation from the Yushan site, which is the closest site of Hemudu culture to the modern coastline. Based on the data gathered, we suggest that the Hemudu culture and subsequent Liangzhu culture developed in the context of regression and were interrupted by two transgressions that occurred during 6300-5600 BP and 5000-4500 BP. The regional ecological environment of the Yushan site alternated between intertidal mudflat and freshwater wetlands induced by sea-level fluctuations in the mid-late Holocene. Though rice was cultivated in the wetland as early as 6700 BP, this cultivation was subsequently discontinued due to the transgression; thus, full domestication of rice did not occur until 5600 BP in this region. Comprehensive analysis of multiple proxies in this study promote the understanding of the relationship between environmental evolution, cultural interruption, and rice domestication.

Multi-centennial–scale climate changes in the Asian monsoonal region significantly affect nearly half of the global population and they have also influenced the evolution of civilizations. However, the relationship between cyclic climate change and civilization remains unclear. Here we present a precisely-dated, high-resolution pollen record from the southern Tibetan Plateau (STP), which reveals ~500-yr and ~ 210-yr cyclic variations in vegetation and precipitation during the last ~3600 years. The results show that ~500-yr and ~ 210-yr rainfall cycles were triggered by changes in the intensity of the Indian Summer Monsoon (ISM) and the Westerlies, respectively. In addition, these two periodicities were almost in-phase with centennial-scale periodic changes in the low-latitude El Nino–Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD), as well as with the high-latitude North Atlantic Oscillation (NAO). Furthermore, the flourishing/demise of the Tubo Dynasty in China corresponds closely with the superimposed wet/dry phases of the ~500-yr and ~ 210-yr cyclic climate changes, suggesting a direct relationship between regional cultural evolution and multi-centennial–scale climatic cyclicity.

Prehistoric human activities were likely influenced by cyclic monsoon climate changes in East Asia. Here we report a decadal-resolution Holocene pollen record from an annually-laminated Maar Lake in Northeast China, a proxy of monsoon climate, together with a compilation of 627 radiocarbon dates from archeological sites in Northeast China which is a proxy of human activity. The results reveal synchronous ~500-year quasi-periodic changes over the last 8000 years. The warm-humid/cold-dry phases of monsoon cycles correspond closely to the intensification/weakening of human activity and the flourishing/decline of prehistoric cultures. Six prosperous phases of prehistoric cultures, with one exception, correspond approximately to warm-humid phases caused by a strengthened monsoon. This ~500-year cyclicity in the monsoon and thus environmental change triggered the development of prehistoric cultures in Northeast China. The cyclicity is apparently linked to the El Niño-Southern Oscillation, against the background of long-term Holocene climatic evolution. These findings reveal a pronounced relationship between prehistoric human activity and cyclical climate change., Long-term climate cycles can potentially influence population dynamics, including those of humans. Here, the authors combine climate and archaeological records from Northeast China over the past 8000 years and demonstrate ~500 year cycles in both the monsoon and human activity.

The production of high-resolution and accurate age models for lake sediments in the Tibetan Plateau (TP) is a prerequisite for subsequent paleoclimatic studies. However, Holocene lake sedimentary records with high-quality age controls from the TP are extremely scarce. Here we present the results of a comparative study of the results of the application of multiple dating techniques (14C, 210Pb, 137Cs) and a paleomagnetic secular variation (PSV) study of the sediments of Angrenjin Co in the southern central TP, during the last 3600 years. The PSV data are verified by comparison with a stacked PSV record from East Asia and with a global geomagnetic field model. The results of 14C-dating, validated by independent 210Pb, 137Cs and PSV dating, together with Bacon age modeling, indicate that the reservoir has an age range of ~2287 ± 58–6434 ± 165 years; in addition, the median offset ages estimated by the Bacon age-depth model range from ~1330 ± 428 to 3102 ± 513 years. This cross-dating approach effectively reduces dating uncertainties for lake sediments in the TP, and it can accommodate a variable reservoir effect. Comparison of the paleomagnetic inclination record from Angrenjin Co with previously published records from Tangra Yumco, Taro Co and Nam Co indicates an overall high degree of similarity, suggesting that the paleomagnetic data from different lakes in the TP are reproducible. In addition, the similar inclination patterns across this large region indicate a common geomagnetic origin.

Using phytolith analysis from a well-dated and high-resolution sediment sequence in the apex of northern Yangtze Delta, we investigate environmental changes, the rise and decline of rice exploitation and possible impacts of environment on rice exploitation during the early mid-Holocene. The phytolith sequence documents a relatively warm and dry interval during ca.9000 to 8200 cal yr BP, followed by climatic amelioration before 7200 cal yr BP. Phytolith evidence indicates that rice exploitation at the apex of northern Yangtze Delta began at 8200 cal yr BP, flourished by 7700 cal yr BP and ceased after 7400 cal yr BP. The first emergence of marine diatom species approximately 7300 cal yr BP likely indicates an accelerated sea-level rise. The apparent correlation of the initiation of rice exploitation with climatic amelioration during the early mid-Holocene suggests that climatic changes may have played an important role in facilitating rice exploitation. Both the ideal climatic conditions and stable sea level enabled flourishing rice exploitation during 8200 to 7400 cal yr BP. Although the climate remained warm and wet after 7400 cal yr BP, local sea-level rise possibly led to the termination of earlier rice exploitation at this site of the northern Yangtze Delta.

The last deglaciation is of great interest because Northern Hemisphere climate has gone through several abrupt changes. We present an n-alkane and compound-specific carbon isotope record of the last deglaciation from the annually laminated sedimentary sequence of Lake Xiaolongwan, northeastern China. The n-alkane distribution suggests that the sparsely distributed vegetation prior to 14.7 ka BP, changed to wood plants and aquatic macrophytes in the early Bolling-Allerod, and was followed by a broadleaved deciduous forest after 11.4 ka BP. In this forest region, where the vegetation is dominated by C3 plants, the compound-specific δ13C value of the long-chain n-alkanes (nC27, nC29 and nC31) is interpreted as a proxy of effective precipitation, while temperature might play a minor secondary role. The positive δ13C27–31 values during the Bolling-Allerod suggest a dry-warm climatic condition, while the negative δ13C27–31 at 13.0–11.4 ka BP indicates a cold-wet climate during the Younger Dryas in this region. Two periods with lower δ13C27–31 occurred at 16.1–16.5 and 17.3–17.7 ka BP and could be associated with the Heinrich event-1a and the Heinrich event-1b, respectively. The synchroneity between the biomarker time series in Lake Xiaolongwan and the δ18O record from the Greenland ice core suggest the dominance of high latitude processes on regional monsoon evolution from the last glacial, the Bolling-Allerod, the Younger Dryas to early Holocene. Regionally, the Okhotsk High might have played an important role for abrupt changes during the glacial/interglacial transition.

Although the summer monsoon is the dominant source of precipitation in the East Asian monsoon region (EAMR), there is long-standing uncertainty about the spatial and temporal variability of precipitation on the centennial time scale. In this study we analyzed two well-dated, high-resolution, published paleoclimatic records in order to determine the variability of precipitation in the EAMR during the Holocene. One record is a decadal-resolution pollen record from an annually-laminated Maar lake in Northeast (NE) China, and the other is a U Th dated, multi-decadal-resolution speleothem record from Central China. Advanced time-series analysis of the two records provides unambiguous evidence for asynchronous summer monsoon rainfall variability on centennial to millennial time scales in the EAMR. The pollen and speleothem records indicate long-term and ~ 500-yr quasi-periodic changes in humid/dry climatic shifts against the background of an insolation-forced climatic trend throughout the past 8580 years. Phases of wetter climate (during ~7000–5500 cal yr BP) and drier climate (during ~1400–300 cal yr BP) in NE China are closely related to different climatic phases in Central China. However, the ~500-yr cyclic rainfall changes in Central China lag those in NE China by several decades to almost two centuries. During the ~500-yr periodic changes in the monsoon, a climatic pattern encapsulated as “Northern drought, southern flooding” prevailed during an El Nino-like phase, whereas the opposite pattern “Southern drought, northern flooding” occurred during a La Nina-like phase. The asynchronous pattern of ~500-yr climatic cyclicity between the northern and southern EAMR may have been caused by the El Nino-Southern Oscillation, linked to low-latitude oceanic and atmospheric interactions.

We present an n-alkane and compound-specific carbon isotope record of the past 9 ka from the annually laminated sedimentary sequence of Lake Xiaolongwan, northeastern China. The n-alkane distribution suggests that Lake Xiaolongwan has undergone a shift from an oligotrophic state with low algal production and little emergent/submerged macrophytes in the early Holocene, to a eutrophic state with high algal production and abundant emergent/submerged macrophytes since the middle Holocene. The pattern of variation observed in the biomarker proxies ACL (the n-alkane average chain length), Paq (aquatic macrophyte versus aquatic macrophyte and terrestrial plant ratio), and LPTP (lake productivity/ terrigenous organic production) is throughout the record similar to that of the total organic carbon. The variation of compound-specific carbon isotopic values in the middle- and short-chain alkanes was mainly regulated by lake productivity and the accumulating organic pool through time. In this forested region, where the vegetation is dominated by C 3 plants, the long-chain n-alkanes (C27eC31) are predominantly derived from leaf wax lipids. The compound-specific d 13 C27e31 value is sensitive to effective precipitation, and therefore represents a useful indicator of regional monsoonal precipitation. Spectral analysis on the d 13 C27e31 time series reveals significant periodicities of 87e89, 205e212, 1020e1050 and 1750e2041 years. On the centennial timescale, the quasi-periodicities around 88 and 210 years suggest a strong link between solar activity and monsoon rainfall. The millennial monsoon cycle in northeastern China is associated with sea surface temperature (SST) variations in two active centers of the summer monsoon, the western Pacific Subtropical High (WPSH) and the Okhotsk High. Increasing SST in the subtropical sea may cause a northwards shift of the WPSH, which extends the monsoon rain band (Meiyu) to northeastern China, and thus increasing rainfall in that region. Meanwhile, decreasing SST in the Okhotsk Sea may strengthen the Okhotsk high, bringing more moisture into northeastern China. We suggest that the Pacific Ocean is a main regulator for summer monsoon rainfall in northeastern China at present and at different time scales during the Holocene.

Here we presented a high-resolution 5350-year pollen record from a maar annually laminated lake in East Asia (EA). Pollen record reflected the dynamics of vertical vegetation zones and temperature change. Spectral analysis on pollen percentages/concentrations of Pinus and Quercus, and a temperature proxy, revealed ∼500-year quasi-periodic cold-warm fluctuations during the past 5350 years. This ∼500-year cyclic climate change occurred in EA during the mid-late Holocene and even the last 150 years dominated by anthropogenic forcing. It was almost in phase with a ∼500- year periodic change in solar activity and Greenland temperature change, suggesting that ∼500-year small variations in solar output played a prominent role in the mid-late Holocene climate dynamics in EA, linked to high latitude climate system. Its last warm phase might terminate in the next several decades to enter another ∼250-year cool phase, and thus this future centennial cyclic temperature minimum could partially slow down man-made global warming.

Phytoliths and biomolecular components extracted from ancient plant remains from Chang’an (Xi’an, the city where the Silk Road begins) and Ngari (Ali) in western Tibet, China, show that the tea was grown 2100 years ago to cater for the drinking habits of the Western Han Dynasty (207BCE-9CE) and then carried toward central Asia by ca.200CE, several hundred years earlier than previously recorded. The earliest physical evidence of tea from both the Chang’an and Ngari regions suggests that a branch of the Silk Road across the Tibetan Plateau, was established by the second to third century CE.

Here we presented a high-resolution 5350-year pollen record from a maar annually laminated lake in East Asia (EA). Pollen record reflected the dynamics of vertical vegetation zones and temperature change. Spectral analysis on pollen percentages/concentrations of Pinus and Quercus and a temperature proxy, revealed ~500-year quasi-periodic cold-warm fluctuations during the past 5350 years. This ~500-year cyclic climate change occurred in EA during the mid-late Holocene and even the last 150 years dominated by anthropogenic forcing. It was almost in phase with a ~500-year periodic change in solar activity and Greenland temperature change, suggesting that ~500-year small variations in solar output played a prominent role in the mid-late Holocene climate dynamics in EA, linked to high latitude climate system. Its last warm phase might terminate in the next several decades to enter another ~250-year cool phase and thus this future centennial cyclic temperature minimum could partially slow down man-made global warming.

A high-resolution multiproxy record, including pollen, foraminifera, and alkenone paleothermometry, obtained from a single core (DG9603) from the Okinawa Trough, East China Sea (ECS), provided unambiguous evidence for asynchronous climate change between the land and ocean over the past 40 ka. On land, the deglacial stage was characterized by rapid warming, as reflected by paleovegetation, and it began ca. 15 kaBP, consistent with the timing of the last deglacial warming in Greenland. However, sea surface temperature estimates from foraminifera and alkenone paleothermometry increased around 20–19 kaBP, as in the Western Pacific Warm Pool (WPWP). Sea surface temperatures in the Okinawa Trough were influenced mainly by heat transport from the tropical western Pacific Ocean by the Kuroshio Current, but the epicontinental vegetation of the ECS was influenced by atmospheric circulation linked to the northern high-latitude climate. Asynchronous terrestrial and marine signals of the last deglacial warming in East Asia were thus clearly related to ocean currents and atmospheric circulation. We argue that ( i ) early warming seawater of the WPWP, driven by low-latitude insolation and trade winds, moved northward via the Kuroshio Current and triggered marine warming along the ECS around 20–19 kaBP similar to that in the WPWP, and ( ii ) an almost complete shutdown of the Atlantic Meridional Overturning Circulation ca. 18–15 kaBP was associated with cold Heinrich stadial-1 and delayed terrestrial warming during the last deglacial warming until ca. 15 kaBP at northern high latitudes, and hence in East Asia. Terrestrial deglacial warming therefore lagged behind marine changes by ca. 3–4 ka.

The origin of millet from Neolithic China has generally been accepted, but it remains unknown whether common millet ( Panicum miliaceum ) or foxtail millet ( Setaria italica ) was the first species domesticated. Nor do we know the timing of their domestication and their routes of dispersal. Here, we report the discovery of husk phytoliths and biomolecular components identifiable solely as common millet from newly excavated storage pits at the Neolithic Cishan site, China, dated to between ca. 10,300 and ca. 8,700 calibrated years before present (cal yr BP). After ca. 8,700 cal yr BP, the grain crops began to contain a small quantity of foxtail millet. Our research reveals that the common millet was the earliest dry farming crop in East Asia, which is probably attributed to its excellent resistance to drought.

Foxtail millet (Setaria italica) and Common millet (Panicum miliaceum) are the oldest domesticated dry farming crops in Eurasia. Identifying these two millets in the archaeobotanical remains are still problematic, especially because the millet grains preserve only when charred. Phytoliths analysis provides a viable method for identifying this important crop. However, to date, the identification of millet phytoliths has been questionable, because very little study has been done on their morphometry and taxonomy. Particularly, no clear diagnostic feature has been used to distinguish between Foxtail millet and Common millet. Here we examined the anatomy and silicon structure patterns in the glumes, lemmas, and paleas from the inflorescence bracts in 27 modern plants of Foxtail millet, Common millet, and closely related grasses, using light microscopy with phase-contrast and microscopic interferometer. Our research shows that five key diagnostic characteristics in phytolith morphology can be used to distinguish Foxtail millet from Common millet based on the presence of cross-shaped type, regularly arranged papillae, Omega-undulated type, endings structures of epidermal long cell, and surface ridgy line sculpture in the former species. We have established identification criteria that, when used together, give the only reliable way of distinguishing between Foxtail millet and Common millet species based on their phytoliths characteristics, thus making a methodological contribution to phytolith research. Our findings also have important implications in the fields of plant taxonomy, agricultural archaeology, and the culture history of ancient civilizations.