Contribution of the Pacific Decadal Oscillation to Global Mean Sea Level Trends: Revisited

Abstract

Abstract Three decades of satellite altimeter observations reveal a continued rise in global mean sea level (GMSL), with the rate of rise reflecting the combined effects of decadal variability and long‐term warming. By decomposing 30‐year running trends of reconstructed sea level over 1950–2019, we quantify the contribution associated with the Pacific Decadal Oscillation (PDO) to the GMSL trend during the satellite altimetry era. Our results indicate that, over 1990–2019, the PDO‐associated contribution to the GMSL trend is 0.45 ± 0.07 mm/yr. This contribution is mediated through steric sea level changes (approximately 0.09 ± 0.03 mm/yr) and ocean mass changes related to land precipitation, evaporation, and runoff (approximately 0.34 ± 0.07 mm/yr). After removing the PDO‐associated influence, the acceleration in 30‐year GMSL trends decreases by about 70%. These findings underscore the importance of accounting for decadal sea level variability to detect the secular acceleration associated with anthropogenic warming.