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This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
The La Niña and El Niño phases of the El Niño-Southern Oscillation (ENSO) have major impacts on regional rainfall patterns around the globe, with substantial environmental, societal and economic implications. Long-term perspectives on ENSO behaviour, under changing background conditions, are essential to anticipating how ENSO phases may respond under future climate scenarios. Here, we derive a 7700-year, quantitative precipitation record using carbon isotope ratios from a single species of leaf preserved in lake sediments from subtropical eastern Australia. We find a generally wet (more La Niña like) mid-Holocene that shifted towards drier and more variable climates after 3200 cal. yr BP, primarily driven by increasing frequency and strength of the El Niño phase. Climate model simulations implicate a progressive orbitally-driven weakening of the Pacific Walker Circulation as contributing to this change. At centennial scales, high rainfall characterised the Little Ice Age (~1450–1850 CE) in subtropical eastern Australia, contrasting with oceanic proxies that suggest El Niño-like conditions prevail during this period. Our data provide a new western Pacific perspective on Holocene ENSO variability and highlight the need to address ENSO reconstruction with a geographically diverse network of sites to characterise how both ENSO, and its impacts, vary in a changing climate.
Author(s): Barr C, Tibby J, Leng MJ, Tyler JJ, Henderson ACG, Overpeck JT, Simpson GL, Cole JE, Phipps SJ, Marshall JC, McGregor GB, Hua Q, McRobie FH
Publication type: Article
Publication status: Published
Journal: Scientific Reports
Online publication date: 07/02/2019
Acceptance date: 28/12/2018
Date deposited: 07/02/2019
ISSN (electronic): 2045-2322
Publisher: Nature Publishing Group
Notes: ReadCube link: https://rdcu.be/blC8V
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