14 October 2013 — Research scientists have found a consistent projection for the future of the El Niño-Southern Oscillation in a warming climate. ENSO drives substantial variation in rainfall and severe weather, which impacts agriculture production, ecosystems and disease in many parts of the world, including Australia.

Using the world’s latest generation of climate models, researchers from the Bureau of Meteorology have uncovered a consistent projection for the future of ENSO, the dominant source of year-to-year variability in the earth’s climate system.

The projections include an intensification of El Niño-driven drying in the western Pacific and rainfall increases in the central and eastern equatorial Pacific.

Dr Scott Power from the Bureau of Meteorology’s Centre for Australian Weather and Climate Research said: “Until now, there has been great uncertainty about the way in which ENSO might actually change in response to global warming – despite scientists investigating the issue for more than two decades.

“Using the world’s latest generation of climate models we discovered a consistent projection for the future of ENSO.

“Projections produced by the models indicate that global warming interferes with the impact that El Niño sea-surface temperature patterns have on 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.

Dr Wenju Cai, senior principal research scientist at the Wealth from Oceans Flagship at the CSIRO, said that during El Niño, countries like Australia experienced low rainfall.

“This study finds that both the wet and dry anomalies will be greater in future El Nino years,” said Mr Cai. “This means that ENSO-induced drought and floods will be more intense in the future.”