Globally, the El Nino-Southern Oscillation (ENSO) is the leading mode of year-to-year climate variability and involves many complex interactions between the ocean and atmosphere. Accurate simulations and predictions of ENSO are important due to its influence on temperature and precipitation patterns in many areas of the world. Progress in ENSO simulation has been made through improved understanding of the physics and dynamics involved; however many challenges in modeling this complex phenomenon remain, especially within the context of a changing climate.

The 4th Climate and Ocean – Variability, Predictability and Change (CLIVAR) Workshop on the Evaluation of ENSO in Climate Models: ENSO in a Changing Climate was held July 8 through July 10, 2015 in Paris, France. This workshop was jointly supported by CPO’s Modeling, Analysis, Predictions, and Projections and Earth System Science programs, as well as other international organizations. The workshop aimed to look into the science of ENSO events, to review the state of understanding of ENSO and potential future changes in its properties, to evaluate current and potential observations and observing systems, and to discuss new developments and metrics for evaluating ENSO in models.