ENSO in a changing climate simulations

El Niño- Southern Oscillation (ENSO) is a tropical Pacific climatic phenomenon occurring every 2-7 years and having devastating global socioeconomic consequences. This thesis provides insight into understanding General Circulation model (GCM)’s large uncertainties in the ENSO dynamics, statistics and ambiguity in future global warming scenario simulations. We provide evidence that the GCM’s simulate correct ENSO characteristics for the wrong reasons, there are compensating atmospheric and oceanic feedback errors. The GCM’s can be significantly improved and the thesis gives directions as to how. It also explains why strong dynamical changes lead to no overall future ENSO variability but affect ENSO predictability.