Wu H. C. auteur aut IRD Dissard Delphine auteur aut IRD Douville E. auteur aut IRD Blamart D. auteur aut IRD Bordier L. auteur aut IRD Tribollet Aline auteur aut IRD Le Cornec Florence auteur aut IRD Pons-Branchu E. auteur aut IRD Dapoigny A. auteur aut IRD Lazareth Claire auteur aut IRD text journalArticle eng text/pdf reformatted digital access Increasing atmospheric CO2 from man-made climate change is reducing surface ocean pH. Due to limited instrumental measurements and historical pH records in the world's oceans, seawater pH variability at the decadal and centennial scale remains largely unknown and requires documentation. Here we present evidence of striking secular trends of decreasing pH since the late nineteenth century with pronounced interannual to decadal-interdecadal pH variability in the South Pacific Ocean from 1689 to 2011 CE. High-amplitude oceanic pH changes, likely related to atmospheric CO2 uptake and seawater dissolved inorganic carbon fluctuations, reveal a coupled relationship to sea surface temperature variations and highlight the marked influence of El Nino/Southern Oscillation and Interdecadal Pacific Oscillation. We suggest changing surface winds strength and zonal advection processes as the main drivers responsible for regional pH variability up to 1881 CE, followed by the prominent role of anthropogenic CO2 in accelerating the process of ocean acidification. specialized 032 9 art. 2543 [13 ] 2018 2041-1723 https://www.documentation.ird.fr/hor/fdi:010073199 10.1038/s41467-018-04922-1 2041-1723 [F B010073199] https://www.documentation.ird.fr/hor/fdi:010073199 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/divers18-08/010073199.pdf IRD - Base Horizon / Pleins textes 2018-09-03 2023-07-11 fdi:010073199 fre