From Pierre Gosselin’s No Tricks Zone:
by Sebastian Lüning and Fritz Vahrenholt
The Taklamakan Desert is the 2nd world’s largest sand desert after the Rub el-Khali Desert in Saudi Arabia. A Chinese-Australian team of scientists lead by Keliang Zhao of the Chinese Academy of Sciences in Peking studied the sediment-profiles from an oasis at the edge of the Taklamakan where they reconstructed the climate of the last 4000 years based on pollen. The scientists published their results in March, 2012.
The study is yet another beautiful example of the global climatic impact of the solar millenial cycles (also see our recent article “New Study in PNAS Confirms Solar Impact Over the Last 9000 Years“ and “Solar Millennium Cycles Regulated the Wet and Dry Periods of the Mediteranean During the Roman Times“, also see pages 68-75 of our book “Die kalte Sonne“.
Figure 2: Reconstruction of the moisture development in the region of study using pollen for the last 4000 years. The shaded gray areas depict wet periods in the Tarim Basin. These coincide with the cold phases in the North Atlantic (numbered 1, 2, 3) and solar weak phases, as described by Bond et al. (2001). Chart from Zhao et al. (2012).
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Climatic variations over the last 4000 cal yr BP in the western margin of the Tarim Basin, Xinjiang, reconstructed from pollen data
Keliang Zhao, Xiaoqiang Li, John Dodson, Pia Atahan, Xinying Zhou, Fiona Bertuch
The nature of Holocene climate patterns and mechanisms in central Asia are open areas of inquiry. In this study, regional vegetation and climate dynamics over the last ca. 4000 years are reconstructed using a high resolution pollen record from the Kashgar oasis, on the western margin of the Tarim Basin, central Asia. Ephedra, Chenopodiaceae and Cannabaceae dominate the pollen assemblages, and Chenopodiaceae/Ephedra ratios and percentages of long-distance transported pollen taxa are used to infer regional variations in moisture and vegetation density. Three periods of increased humidity are identified, from ca. 4000–2620 cal yr BP, ca. 1750–1260 cal yr BP and ca. 550–390 cal yr BP and these periods coincide with the respective Holocene Bond Events 2, 1 and 0, which are reported in the North Atlantic. Any increase in strength, or southward migration, of the mid-latitude westerlies would result in more precipitation and meltwater on mountains surrounding the study site. Warm and dry conditions are detected between ca.1260 and 840 cal yr BP (AD 690–1110), and cool and wet conditions are detected between ca. 840 and 680 cal yr BP (AD 1110–1270), during the Medieval Warm Period (ca. AD 800–1200). The climate variations in the Kashgar region over the last 4000 years appear to have been dominated by changes to the westerly circulation system and glacier dynamics on surrounding mountains. However, the question of whether the Asian monsoon delivers precipitation to the western Tarim Basin, a region that is influenced by several climate systems, is still open to debate.
► New pollen records for the last 4000 cal yr BP in the western Tarim Basin.
► Four humid and three dry periods were identified in the study region.
► Increase in the strength of the westerlies resulted in the three humid periods.
► The climate was warm and dry during the early Medieval Warm Period (AD 690–1110).