ENSO is the most dominant source of interannual climate variability globally. Its understanding and seasonal and climate prediction is of vital importance for societies affected by ENSO impacts. This session invites contributions from scientists who try to understand the dynamics of ENSO, including multi-scale interactions, from those who study paleo ENSO variability, ENSO impacts on climate, society and ecosystems and from those who are involved in ENSO seasonal forecasting and climate change projections. Studies using new approaches to understand multi-model ENSO diversity are especially welcomed.