A Stochastic View of El Nino I

In this presentation, I review the paradigm of El Nino as a stochastically-forced system. In particular, the interplay of stochastic forcing and non-normal linear dynamics explains a large part of El Nino variability. Since controlled laboratory simulations of climate cannot be performed (except on computers), careful falsification, as opposed to verification, of theory by data was required to establish this paradigm. I shall describe this procedure and, in so doing, show how complex a simple model can be.