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The Western Liaohe River Basin in northeastern China is one of the cradles of ancient Chinese civilization. Archaeological records from this region indicate that human occupation began about 8000 years ago and that agriculture and pastoralism were important activities from an early stage. Very little is known, however, about the effects that these activities had upon the landscape. This paper presents the results of a palaeoecological study from a 3.6 m sedimentary sequence in a relict oxbow lake in the Western Liaohe River Basin of southeast Inner Mongolia. The 5400-yr sequence indicates that human activities had a noticeable impact on an apparently open landscape. Buckwheat cultivation began as early as 5400 cal. yr BP with intensification of agricultural activities from approximately 4700 cal. yr BP. Nitrophilous plants such as Solanum and Cerastium, and also Artemisia were growing in the region at certain times, linked with fluctuations in the δ15N record and probably indicative of increased pastoralism and unintentional/intentional manuring. Burning was probably used for clearance of the steppe vegetation for agriculture with a close relationship apparent between increased influx of microfossil charcoal and the presence of buckwheat. Superimposed upon this record of human impact is also clear indication of three significant intervals of climate change between 2900 and 2600, 1200 and 600 and 600 and 30 cal. yr BP. The latter two are discussed in relation to the 'Mediaeval Warm Period' and 'Little Ice Age' apparent in sedimentary sequences across the Northern Hemisphere. Discussions are therefore made in terms of the impact that both climate change and ancient Chinese civilizations had upon shaping the present day landscape and vegetation. [ABSTRACT FROM AUTHOR]

A consensus on Holocene climate variability at the modern northern fringe of the East Asian summer monsoon (EASM) region remains elusive. Here, we present a pollen‐based reconstruction of vegetation history and associated climate variations of a sediment core from Huangqihai Lake, central Inner Mongolia. During 10.7 to 8.8 cal kaBP, typical steppe with small patches of forest dominated the lake area, suggesting a moderately wet climate, followed by ameliorating climatic conditions until 8.0 cal kaBP as deduced by the expansion of forest. Typical steppe recovered the lake area between 8.0 and 7.2 cal kaBP, reflecting a deterioration of climatic conditions; in combination with other proxy records in the study region, we noticed that severe aridity was prevailed in the lake area between 8.0 and 7.6 cal kaBP. During 7.2 to 3.2 cal kaBP, abundant tree pollen indicated dominance of forest‐steppe around the lake, marking regionally wet conditions. A notable absence of broadleaved trees after 5.2 cal kaBP reveals a slight drying trend, and climate deterioration from 4.5 to 4.1 cal kaBP might be linked to the 4.2 ka event. After 3.2 cal kaBP, a transition to steppe was associated with dry conditions in the region. Based on our pollen record and prior paleoclimatic reconstructions in the Huangqihai Lake region, there was a generally‐accepted, stepwise shift to a wet climate during the early Holocene, an overall humid climate from 7.2 to 3.2 cal kaBP, and then severe drought for the rest of the Holocene. Moreover, regional comparisons among pollen records derived from lakes situated in the temperate steppe region suggested a roughly synchronous pattern of vegetation and climate changes during the Holocene and demonstrated an intensified EASM during the middle Holocene. [ABSTRACT FROM AUTHOR]

Luminescence dating of the fluvial and lacustrine sediments from the Sala Us River valley at the south edge of the Mu Us Desert, central Inner Mongolia, is reported. The study region lies in the northwestern marginal zone of the east Asian summer monsoon and is sensitive to climate change. The dating results combined with environmental proxies indicate that the Holocene Climate Optimum period, took place from 8.5 to 5 ka ago and was marked by lake development. After ~5 ka ago, the region became arid, as inferred from lake regression and fluvial activity. Deposition of fluvial sediments lasted from ~5 ka to ~2 ka ago. At about 2 ka ago, incision of the Sala Us River was initiated into the underlying sediments, with a down-cutting rate of ~3–4 cm/yr. Since 2 ka ago, human activities also played an important role in causing environmental change in the region. [ABSTRACT FROM PUBLISHER]

The impact of orbital parameters on the climate of China in the Holocene is simulated from 11kaBP to 0kaBP with an interval of 1ka using National Center for Atmospheric Research (NCAR) Community Atmosphere Model version 2 (CAM2). The geographic distributions of summer precipitation around both 9kaBP and 4kaBP were realistically captured by CAM2, compared to the proxy data collected from 80 stations. Among all orbital parameters, the precession plays a major role in computing solar radiation, which dominates the variations of summer precipitation over China during the Holocene. The summers around 9kaBP were the wettest in China. Later on, the precipitation gradually reduced to the minimum around 0kaBP by about 10%. This tremendous change occurred from the Northeast China and the eastern Inner Mongolia extending southwestwards to the Qinghai-Tibet Plateau, especially over the Qinghai-Tibet Plateau. [ABSTRACT FROM AUTHOR]

A 5.3 m lake core was drilled in Baahar Nuur Lake in the Ordos Plateau, and measurements of mean grain size, organic δ13C (δ13Corg), organic carbon content (TOC), C/N, carbonate content, carbonate δ13C (δ13Ccar) and δ18O (δ18Ocar) were conducted for retrieving the Holocene chronosequence of climatic changes based on 15 AMS 14C dates. The record documented four major stages of climate change in the Ordos Plateau: (IV) a cold and dry condition before ~7.65 14C ka BP; (III) a warm and humid stage between ~7.65 and ~5.40 ka BP; (II) a generally drier and cooler climate since ~5.40 ka BP with two humid events occurring from ~4.70 to ~4.60 ka BP and from ~4.20 to ~3.70 ka BP, and (I) a dry climate characterized by complete desiccation of the lake after 3.70 ka BP. Stage Ill can be further divided Into three sub-stages: (IIIa) a warm and humid episode from ~7.65 to ~6.70 ka BP, (IIIb) a warm and relatively dry episode from ~6.70 to ~6.20 ka BP, and (IIIc) the magthermal and maghumid episode of the Holocene from ~6.20 to ~5.40 ka BP. [ABSTRACT FROM AUTHOR]