Multi-model average (MMA) of the difference between twentieth-century and twenty-first-century filtered surface temperature and precipitation anomalies in El Niño years. a, c, e, g, Surface temperature (ST); b, d, f, h, precipitation. a, b, RCP8.5. c, d, RCP4.5. e, f, 1% CO2. g, h, The CMIP3 models were forced using SRES A2. The corresponding averages for El Niño–La Niña years are very similar. Graphic: Power, et al., 2013By Matt McGrath, Environment correspondent
13 October 2013

(BBC News) – Scientists say they are more certain than ever about the impact of global warming on a critical weather pattern. The El Niño-Southern Oscillation (ENSO) occurs in the Pacific Ocean but plays an important part in the world’s climate system. Researchers have until now been unsure as to how rising temperatures would affect ENSO in the future. But this new study suggests that droughts and floods driven by ENSO will be more intense. […] For years, scientists have been concerned about how this sensitive weather system might be changed by rising temperatures from global warming. Now, in this new paper, published in the journal Nature, researchers give their most “robust” projections yet. Using the latest generation of climate models, they found a consistent projection for the future of ENSO. According to the lead author, Dr Scott Power from the Australian Bureau of Meteorology, global warming interferes with the way El Niño temperature patterns affect rainfall. “This interference causes an intensification of El Niño-driven drying in the western Pacific and rainfall increases in the central and eastern equatorial Pacific,” he said. According to Dr Wenju Cai, a scientist at the Commonwealth Scientific and Industrial Research Organisation (CSIRO), who was not involved with the study, the paper is “significant”. […] “This study finds that both wet and dry anomalies will be greater in future El Niño years. This means that ENSO-induced droughts and floods will be more intense in the future.” [more]

Global warming will increase intensity of El Nino, scientists say