title: Pacific freshening drives Pliocene cooling and Asian monsoon intensification.
abstract: The monsoon is a fundamental component of Earth's climate. The Pliocene warm period is characterized by long-term global cooling yet concurrent monsoon dynamics are poorly known. Here we present the first fully quantified and calibrated reconstructions of separate Pliocene air temperature and East Asian summer monsoon precipitation histories on the Chinese Loess Plateau through joint analysis of loess/red clay magnetic parameters with different sensitivities to air temperature and precipitation. East Asian summer monsoon precipitation shows an intensified trend, paradoxically at the same time that climate cooled. We propose a hitherto unrecognized feedback where persistently intensified East Asian summer monsoon during the late Pliocene, triggered by the gradual closure of the Panama Seaway, reinforced late Pliocene Pacific freshening, sea-ice development and ice volume increase, culminating in initiation of the extensive Northern Hemisphere glaciations of the Quaternary Ice Age. This feedback mechanism represents a fundamental reinterpretation of the origin of the Quaternary glaciations and the impact of the monsoon.
authors: MOE Key Laboratory of Western China's Environmental Systems, Collaborative Innovation Centre for Arid Environments and Climate Change, Lanzhou University, Lanzhou 73000, China.
authors: Junsheng
authors: J
authors: Nie
authors: 1] Centre for Quaternary Research, Department of Geography, Royal Holloway University of London, Egham, Surrey, TW20 0EX, UK [2].
authors: Thomas
authors: T
authors: Stevens
authors: State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, P. O. Box 17, 710075, China.
authors: Yougui
authors: Y
authors: Song
authors: Graduate School of Oceanography, University of Rhode Island, South Ferry Road, Narragansett, RI 02882, USA.
authors: John W
authors: JW
authors: King
authors: MOE Key Laboratory of Western China's Environmental Systems, Collaborative Innovation Centre for Arid Environments and Climate Change, Lanzhou University, Lanzhou 73000, China.
authors: Rui
authors: R
authors: Zhang
authors: MOE Key Laboratory of Western China's Environmental Systems, Collaborative Innovation Centre for Arid Environments and Climate Change, Lanzhou University, Lanzhou 73000, China.
authors: Shunchuan
authors: S
authors: Ji
authors: MOE Key Laboratory of Western China's Environmental Systems, Collaborative Innovation Centre for Arid Environments and Climate Change, Lanzhou University, Lanzhou 73000, China.
authors: Lisha
authors: L
authors: Gong
authors: Graduate School of Oceanography, University of Rhode Island, South Ferry Road, Narragansett, RI 02882, USA.
authors: Danielle
authors: D
authors: Cares