Cai W. J. auteur aut IRD Lengaigne Matthieu auteur aut IRD Borlace S. auteur aut IRD Collins M. auteur aut IRD Cowan T. auteur aut IRD McPhaden M. J. auteur aut IRD Timmermann A. auteur aut IRD Power S. auteur aut IRD Brown J. auteur aut IRD Menkès Christophe auteur aut IRD Ngari A. auteur aut IRD Vincent E. M. auteur aut IRD Widlansky M. J. auteur aut IRD text journalArticle eng text/pdf born digital access The South Pacific convergence zone (SPCZ) is the Southern Hemisphere's most expansive and persistent rain band, extending from the equatorial western Pacific Ocean southeastward towards French Polynesia(1,2). Owing to its strong rainfall gradient, a small displacement in the position of the SPCZ causes drastic changes to hydroclimatic conditions and the frequency of extreme weather events-such as droughts, floods and tropical cyclones-experienced by vulnerable island countries in the region(1-7). The SPCZ position varies from its climatological mean location with the El Nino/Southern Oscillation (ENSO), moving a few degrees northward during moderate El Nino events and southward during La Nina events(2,5,6). During strong El Nino events, however, the SPCZ undergoes an extreme swing-by up to ten degrees of latitude toward the Equator-and collapses to a more zonally oriented structure(5) with commensurately severe weather impacts(5,8-11). Understanding changes in the characteristics of the SPCZ in a changing climate is therefore of broad scientific and socioeconomic interest. Here we present climate modelling evidence for a near doubling in the occurrences of zonal SPCZ events between the periods 1891-1990 and 1991-2090 in response to greenhouse warming, even in the absence of a consensus on how ENSO will change(12-14). We estimate the increase in zonal SPCZ events from an aggregation of the climate models in the Coupled Model Intercomparison Project phases 3 and 5 (CMIP3(15) and CMIP5) multi-model database that are able to simulate such events. The change is caused by a projected enhanced equatorial warming in the Pacific(16) and may lead to more frequent occurrences of extreme events across the Pacific island nations most affected by zonal SPCZ events. specialized 032 021 488 7411 365-369 + 1 p. 2012 0028-0836 https://www.documentation.ird.fr/hor/fdi:010057110 10.1038/nature11358 0028-0836 [F B010057110] https://www.documentation.ird.fr/hor/fdi:010057110 https://www.documentation.ird.fr/intranet/publi/2012/09/010057110.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2012-10-03 2017-08-23 fdi:010057110 fre