Based on an absolutely dated stalagmite δ18O record from Yunnan province, China, we reconstructed monsoon precipitation variations in southwest China since 1760 AD with a resolution of about 2 years. Combining the speleothem δ18O and observed rainfall records, we find an overall decreasing trend in monsoon precipitation in this region and suggest that the recent drought in 2009–2012 AD has been the driest since 1760 AD. Our speleothem record is consistent with the monsoon precipitation records reconstructed from tree rings in the Nepal Himalaya and southeastern Tibetan Plateau. However, it is anti-correlated with a speleothem record from central India, which confirms the observed anti-phase variations of Indian monsoon precipitation with moistures from the Bay of Bengal and Arabian Sea on multi-decadal to centennial timescales during historical time. The long-term warming of tropical ocean may have caused the decrease of the land-sea thermal gradient and the amount of moisture transported from the Bay of Bengal, which may reduce precipitations in southwest China during the last 240 years. On decadal scale, El Nińo-like conditions of tropical Pacific sea surface temperature may cause drought in this region. Climate model simulations suggest El Niño-like conditions exist in tropical Pacific under global warming scenarios. As a result, it is crucial to have adaptive strategies to overcome future declines in precipitation and/or drought events in southwest China.
Bibliographical noteFunding Information:
The final version of the manuscript benefited for constructive suggestions from three anonymous reviewers. We gratefully acknowledge the National Key Basic Research Program of China (2013CB955902), National Natural Science Foundation of China (41372192; 41230524), West Light Foundation of Chinese Academy of Sciences, and Youth Innovation Promotion Association of Chinese Academy of Sciences (2012295) for funding this research. C.-C. Shen received financial support from MOST (104-2119-M-002-003). H. Cheng and R. L. Edwards received financial support from the U.S. NSF (EAR-0908792 and EAR-1211299).
© 2016, Springer-Verlag Berlin Heidelberg.
- El Niño
- Southwest China
- Tropical SST