Scientists see a large amount of variability in the El Niño-Southern Oscillation (ENSO) when looking back at climate records from thousands of years ago. Without a clear understanding of what caused past changes in ENSO variability, predicting the climate phenomenon's future is a difficult task. A new study shows how this climate system responds to various pressures, such as changes in carbon dioxide and ice cover, in one of the best models used to project future climate change.
http://www.sciencedaily.com/releases/2014/12/141205114015.htm