Widlansky M. J. auteur aut IRD Timmermann A. auteur aut IRD Stein K. auteur aut IRD McGregor S. auteur aut IRD Schneider N. auteur aut IRD England M. H. auteur aut IRD Lengaigne Matthieu auteur aut IRD Cai W. J. auteur aut IRD text journalArticle eng text/pdf born digital access The South Pacific Convergence Zone (SPCZ) is the largest rainband in the Southern Hemisphere and provides most of the rainfall to southwest Pacific island nations. In spite of various modelling efforts, it remains uncertain how the SPCZ will respond to greenhouse warming. Using a hierarchy of climate models we show that the uncertainty of SPCZ rainfall projections in present-generation climate models can be explained as a result of two competing mechanisms. Higher tropical sea surface temperatures lead to an overall increase of atmospheric moisture and rainfall whereas weaker sea surface temperature gradients dynamically shift the SPCZ northeastward and promote summer drying in areas of the southwest Pacific. On the basis of a multi-model ensemble of 76 greenhouse warming experiments and for moderate tropical warming of 1-2 degrees C we estimate a 6% decrease of SPCZ rainfall with a multi-model uncertainty exceeding +/- 20%. For stronger tropical warming exceeding 3 degrees C, a tendency for a wetter SPCZ region is identified. specialized PACIFIC SUD 032 3 4 417-423 2013 1758-678X https://www.documentation.ird.fr/hor/fdi:010060371 10.1038/nclimate1726 1758-678X [F B010060371] https://www.documentation.ird.fr/hor/fdi:010060371 https://www.documentation.ird.fr/intranet/publi/2013/07/010060371.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2013-07-29 2017-08-23 fdi:010060371 fre