Our planet is covered by two thin layers of fluid - the atmosphere and the oceans - the state of which is of enormous relevance to society. Understanding how our atmosphere and oceans work together to produce the present day climate and how that climate might change in the future is a major objective of atmosphere-ocean science. The kinds of phenomena that are studied in this discipline are wide ranging, El Nino and global warming are but two examples. To make progress in this field, it is necessary to combine observations of the natural environment with theoretical models based on such observations. The last several decades have seen major advances in our ability to observe the Earth, in part due to the developments in satellite technology, as well as major advances in our ability to construct predictive models of the atmosphere and oceans, the latter driven partly by advances in computing technology. In the coming decade, the observational database will increase and through continued theoretical studies so will our understanding of how the atmosphere and oceans work. The challenge of obtaining observations on the global scale and the complexity of this coupled dynamical fluid system make atmosphere-ocean science an exciting field of study.