Pacific decadal variability over the last 2000 years and implications for climatic risk

• Published in: Communications Earth & Environment
• Main Authors: Vance, TR, Kiem, AS, Jong, LM, Roberts, JL, Plummer, CT, Moy, AD, Curran, MAJ, van Ommen, TD
• Format: Article in Journal/Newspaper
• Language: English
• Published: Nature Publishing Group 2022
• Subjects: Earth Sciences; Physical geography and environmental geoscience; Natural hazards; Antarctic; Pacific; Antarc*
• Online Access: https://doi.org/10.1038/s43247-022-00359-z; http://ecite.utas.edu.au/149044

The Interdecadal Pacific Oscillation, an index which defines decadal climate variability throughout the Pacific, is generally assumed to have positive and negative phases that each last 20-30 years. Here we present a 2000-year reconstruction of the Interdecadal Pacific Oscillation, obtained using information preserved in Antarctic ice cores, that shows negative phases are short (7 5 years) and infrequent (occurring 10% of the time) departures from a predominantly neutral-positive state that lasts decades (61 56 years). These findings suggest that Pacific Basin climate risk is poorly characterised due to over-representation of negative phases in post-1900 observations. We demonstrate the implications of this for eastern Australia, where drought risk is elevated during neutral-positive phases, and highlight the need for a re-evaluation of climate risk for all locations affected by the Interdecadal Pacific Oscillation. The initiation and future frequency of negative phases should also be a research priority given their prevalence in more recent centuries.