干旱区生态环境知识资源中心

The first contribution on the high-resolution multi-proxy palaeoclimate, records elucidating the Late Holocene (past similar to 3500 years) climate history of the Uttaranchal Himalaya, comes from a well-dated 1.24-m thick Dhakuri peat deposit in the Kumaon Higher Himalaya. Century-scale records indicate that the Pinder Valley climate was predominantly cold between similar to 3500 and 1600 cal yr BY, with two distinct dry episodes during 3300-2300 and 2100 - ca. 1600 cal yr B.P., separated by 3500-3300 and 2300-2100 cal yr B.P. periods of relatively moist conditions. Except for a centennial cold/dry event of 740-640 cal yr B.P. (similar to 1260-1360 cal AD), the climate shows progressive increase in wetness until the present, with higher temperatures for 1600-740 cal yr B.P. (similar to 400-1260 cal AD), 640-460 cal yr B.P. (similar to 1360-1540 cal AD), and 270-57 cal yr B.P. (similar to 1730-1940 cal AD) intervals, and relatively cold conditions during intermittent periods. These climatic events are at variance with the late Holocene climate records from Bangong Co and the Sumxi Lake of western Tibet, but show good correspondence with contemporaneous records from the Dunde Ice cap, Central Nepal, the Ganga Plain, the Thar Desert and the Arabian Sea.

Significantly warm and moist climate documented between ca. 1600 and 740 cal yr B.P. (ca. 400-1260 cal AD) represents the Medieval Warm Period whereas the predominantly cold climate that prevailed between 460 and 270 cal yr B.P. (similar to 1540-1730 cal AD) marks the Little Ice Age event in the Kumaon Higher Himalaya. Upper tree-line trend deciphered from the pollen-inferred vegetation history indicates that it has ascended at an average rate of 1.5 m altitude/yr to around 900 m altitude since ca. 1360 cal AD (640 cal yr B.P.).