Small fluctuations in the Pacific climate can have global impacts, particularly in drought-prone regions. While we have a solid foundation for interpreting interannual fluctuations in the the Pacific, our understanding of longer-term change is quite poor. This is in part because the observational record is limited, and in part because we don't have a good understanding of the drivers and mechanisms of decadal to century times-scale climate change in the region. Here I will present  observational results together with a hierarchy of climate models to identify the role of anthropogenic greenhouse gases and aerosols in driving Pacific climate change. I will also present some new ideas on the role of natural processes in the coupled ocean-atmosphere system, in particular cloud feedbacks, and their importance for predicting future change.