Abrupt Freshening Since the Early Little Ice Age in Lake Sayram of Arid Central Asia Inferred From an Alkenone Isomer Proxy

Since the Little Ice Age, most glaciers in the Tien Shan mountains have been retreating. Owing to an increase in precipitation in most parts of the mountains during the late 1950s to early 1970s, the percentage of receding glaciers and the speed of retreat have tended to decrease in the 1970s. However, the general trend of continuous glacier retreat remains unchanged, in part because the summer air temperature shows no tendency to decrease.In the Tien Shan mountains, as the degree of climatic continentality increases the mass balance becomes more dependent on summer temperature, and accumulation and ablation tend to be lower. Therefore, the responses of glaciers to climatic fluctuations in more continental areas are not synchronous with those in less continental areas, and the amplitude of the glacier variations becomes smaller.

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High-resolution leaf wax carbon and hydrogen isotopic record of the late Holocene paleoclimate in arid Central Asia

Climate of the Past ◽

10.5194/cp-11-619-2015 ◽

2015 ◽

Vol 11 (4) ◽

pp. 619-633 ◽

Cited By ~ 54

Author(s):

B. Aichner ◽

S. J. Feakins ◽

J. E. Lee ◽

U. Herzschuh ◽

X. Liu

Keyword(s):

Central Asia ◽

Late Holocene ◽

Large Scale ◽

Climate Model ◽

Precipitation Amount ◽

Ice Age ◽

Late Winter ◽

Arid Central Asia ◽

Leaf Wax ◽

D Values

Abstract. Central Asia is located at the confluence of large-scale atmospheric circulation systems. It is thus likely to be highly susceptible to changes in the dynamics of those systems; however, little is still known about the regional paleoclimate history. Here we present carbon and hydrogen isotopic compositions of n-alkanoic acids from a late Holocene sediment core from Lake Karakuli (eastern Pamir, Xinjiang Province, China). Instrumental evidence and isotope-enabled climate model experiments with the Laboratoire de Météorologie Dynamique Zoom model version 4 (LMDZ4) demonstrate that δ D values of precipitation in the region are influenced by both temperature and precipitation amount. We find that these parameters are inversely correlated on an annual scale, i.e., the climate has varied between relatively cool and wet and more warm and dry over the last 50 years. Since the isotopic signals of these changes are in the same direction and therefore additive, isotopes in precipitation are sensitive recorders of climatic changes in the region. Additionally, we infer that plants use year-round precipitation (including snowmelt), and thus leaf wax δ D values must also respond to shifts in the proportion of moisture derived from westerly storms during late winter and early spring. Downcore results give evidence for a gradual shift to cooler and wetter climates between 3.5 and 2.5 cal kyr BP, interrupted by a warm and dry episode between 3.0 and 2.7 kyr BP. Further cool and wet episodes occur between 1.9 and 1.5 and between 0.6 and 0.1 kyr BP, the latter coeval with the Little Ice Age. Warm and dry episodes from 2.5 to 1.9 and 1.5 to 0.6 kyr BP coincide with the Roman Warm Period and Medieval Climate Anomaly, respectively. Finally, we find a drying tend in recent decades. Regional comparisons lead us to infer that the strength and position of the westerlies, and wider northern hemispheric climate dynamics, control climatic shifts in arid Central Asia, leading to complex local responses. Our new archive from Lake Karakuli provides a detailed record of the local signatures of these climate transitions in the eastern Pamir.

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TIMING OF THE LITTLE ICE AGE GLACIAL ADVANCES IN THE EASTERN TIAN SHAN, CENTRAL ASIA

10.1130/abs/2017am-305176 ◽

2017 ◽

Author(s):

Yanan Li ◽

◽

Yingkui Li ◽

Jonathan M. Harbor ◽

Gengnian Liu ◽

...

Keyword(s):

Central Asia ◽

Little Ice Age ◽

Ice Age ◽

Tian Shan

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Humid and cold periods in the last 5600 years in Arid Central Asia revealed by palynology of Picea schrenkiana from Issyk-Kul

The Holocene ◽

10.1177/0959683620972776 ◽

2020 ◽

pp. 095968362097277

Author(s):

Suzanne AG Leroy ◽

Santiago R Giralt

Keyword(s):

Central Asia ◽

Bronze Age ◽

Tien Shan ◽

Ice Age ◽

Forest Belt ◽

Pollen Record ◽

Picea Schrenkiana ◽

Arid Central Asia ◽

Mountain Glaciers ◽

Ancient Silk Road

Central Asia, with its high mountains, despite its location between Europe and eastern Asia remains a data poor area. However, mountain glaciers are strongly affected by global change and have a wide-ranging impact. A new pollen record over the last 5600 years shows the extension of a dry Artemisia steppe around Lake Issyk-Kul, with a slightly wetter period from 4.5 to 2.7 ka BP (less Ephedra). Picea schrenkiana forest growing on north-facing slopes of the northern Tien Shan Range, are exposed to Westerlies-related precipitation. The pollen record of Picea is therefore a very good marker of wetter and cold conditions. A comparison to a nearby synchronous pollen record at a higher altitude indicates that the whole forest belt moved down, and that it was not a downwards extension of the lower forest limit only. Four cold and humid phases were evidenced over the last 5.6 ka: 5.5 ka, 4.2 ka and following centuries, 3.2 ka and following centuries (before the end of the Bronze Age) and finally the Little Ice Age, with the latter two being more strongly expressed. These climatic changes, in agreement with other Arid Central Asia investigations, corroborate the driving role of the Westerlies far inland. Human activities were more intense in the Mid and Late Bronze Age (4.5–3.2 ka) and in the last 800 years, confirmed by archaeological and historical information. Issyk-Kul and surrounding rich pastureland were most likely an important step in the ancient Silk Road.

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Humidity changes and possible forcing mechanisms over the last millennium in arid Central Asia

10.5194/cp-2021-137 ◽

2021 ◽

Author(s):

Shengnan Feng ◽

Xingqi Liu ◽

Feng Shi ◽

Xin Mao ◽

Yun Li ◽

...

Keyword(s):

High Resolution ◽

Central Asia ◽

Southern Oscillation ◽

Atlantic Multidecadal Oscillation ◽

Warm Period ◽

Ice Age ◽

Wavelet Coherence ◽

Last Millennium ◽

Arid Central Asia ◽

Forcing Mechanisms

Abstract. Hydroclimate changes have exerted a significant influence on the historical trajectory of ancient civilizations in arid Central Asia where the central routes of the Silk Road have been hosted. However, the climate changes at different time scales and their possible forcing mechanisms over the last millennium remain unclear due to low-resolution records. Here, we provide a continuous high-resolution humidity history in arid Central Asia over the past millennium based on the ~1.8-year high-resolution multiproxy records with good chronological control from Lake Dalongchi in the central Tianshan Mountains. Generally, the climate was dry during the Medieval Warm Period (MWP) and Current Warm Period (CWP), and wet during the Little Ice Age (LIA), which could be attributed to the influence of the North Atlantic Oscillation (NAO) and the Atlantic Multidecadal Oscillation (AMO). Furthermore, we find that the humidity oscillation was dramatic and unstable at multidecadal to century-scale, especially within the LIA. The continuous wavelet analysis and wavelet coherence show that the humidity oscillation is modulated by the Gleissberg cycle at the century-scale and by the quasi-regular period of El Niño-Southern Oscillation (ENSO) at the multidecadal scale. Our findings suggest that the effect of the solar cycle and the quasi-regular period of ENSO should be seriously evaluated for hydroclimate predictions and climate simulations in arid Central Asia in the future.

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Climate change and Silk Road civilization in the arid central Asia

10.5194/egusphere-egu2020-7335 ◽

2020 ◽

Author(s):

Fahu Chen ◽

Jianhui Chen ◽

Guanghui Dong ◽

Wei Huang ◽

Juzhi Hou ◽

...

Keyword(s):

Climate Change ◽

Central Asia ◽

Central Government ◽

Silk Road ◽

Ice Age ◽

Humid Climate ◽

Arid Central Asia ◽

Decadal Scale ◽

Ancient Civilizations ◽

The Silk Road

The arid central Asia composed of northwestern China and central Asia, is one of the most arid regions in the mid-latitudes and also the core area of the Silk Road civilization. Climate have dramatically changed during Holocene in the region. Prior to 6 ka, moisture conditions increased gradually, and then rapidly, with the most humid period occurring during the late Holocene. Over the last millennium, a dry climate during the Medieval Warm Period and a wet climate during the Little Ice Age is present on the centennial timescale. Instrumental observations showed that precipitation, moisture, and stream runoff all have gradually increased on the decadal scale under global warming. Comparing these results to those in the mid-latitude monsoonal Asia and Mediterranean, the moisture evolution since the Holocene over westerlies Asia featured unique characteristics on various timescales. We proposed the theoretical framework of a &#8216;westerlies-dominated climatic regime&#8217; (WDCR) for hydroclimatic changes. Further studies of physical mechanisms showed that external factors e.g. orbital-induced insolation changes generated WDCR on the sub-orbital timescale, while a circum-global teleconnection/Silk Road pattern was the most important factor responsible for WDCR on the centennial and decadal timescales. Climate change has impacted on the civilization evolution along the Silk road in arid central Asia. The oasis route in this region played a significant role in the development of trans-Eurasia exchange since the late third Millennium BCE. Such route laid the foundation for the formation of ancient Silk Road during the second century BCE that accounted for the most important center for civilization evolution in the planet till the sixteenth century CE. Multi-discipline studies suggest that special warm-humid climate might have facilitated the rise and development of ancient empires, e.g. Tubo Empire (618-842 CE) in and around the high Tibetan Plateau. But climate deterioration, especially severe droughts lasting decades-centuries, triggered the expansion of deserts and shrinkage of oases along the Silk Road. Such land degradation led to the delayed onset of transcontinental exchange, the decline of ancient civilizations such as ancient Loulan Kingdom (176 BCE-630 CE), and the abandonment of Dunhuang area between 1539-1723 CE by Chinese central government that was ascribed as a landmark event for the end of the traditional Silk Road. Further analysis proposed that the evolution of ancient civilizations was likely influenced by precipitation variation in surrounding mountains instead of basins in arid areas of the Silk Road.

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Relation between recent glacier variations and climate in the Tien Shan mountains, central Asia

Annals of Glaciology ◽

10.3189/1992aog16-1-11-16 ◽

1992 ◽

Vol 16 ◽

pp. 11-16 ◽

Cited By ~ 7

Author(s):

Liu Chaohai ◽

Han Tianding

Keyword(s):

Mass Balance ◽

Central Asia ◽

Air Temperature ◽

Little Ice Age ◽

General Trend ◽

Summer Temperature ◽

Tien Shan ◽

Ice Age ◽

Climatic Fluctuations ◽

Tien Shan Mountains

Since the Little Ice Age, most glaciers in the Tien Shan mountains have been retreating. Owing to an increase in precipitation in most parts of the mountains during the late 1950s to early 1970s, the percentage of receding glaciers and the speed of retreat have tended to decrease in the 1970s. However, the general trend of continuous glacier retreat remains unchanged, in part because the summer air temperature shows no tendency to decrease.In the Tien Shan mountains, as the degree of climatic continentality increases the mass balance becomes more dependent on summer temperature, and accumulation and ablation tend to be lower. Therefore, the responses of glaciers to climatic fluctuations in more continental areas are not synchronous with those in less continental areas, and the amplitude of the glacier variations becomes smaller.

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