Uncertainty in Pacific decadal oscillation indices does not contribute to teleconnection instability

ABSTRACT The Pacific decadal oscillation (PDO) has been used extensively to understand low‐frequency climate variability and its impact on ecological and hydrological systems. In the last few years, however, numerous studies have identified various weaknesses in the PDO paradigm. These range from disagreement between proxy‐based reconstructions to instability in teleconnections to discrepancy between the publicly available indices. The potential impact of differences between indices on teleconnection stability is evaluated using the 20th Century Reanalysis and Climatic Research Unit Time‐Series (CRU TS) 3.22 data. While disagreements between the indices may influence the interpretation of climate drivers in particular years, they do not appear to contribute to teleconnection instability in any significant way. Ruling out this simple explanation for teleconnection instability provides further evidence that the PDO is too simplistic a framework for understanding Pacific atmosphere–ocean impacts on remote climate and suggests that variable relationships between the PDO and climate are likely related to the complex origins of this variability.