So far, we have studiously avoided discussing the circulations of atmospheres or oceans, or indeed fluid mechanics of any type, with the exception of a brief foray into compressible one-dimensional hydrodynamics in Section 8.7.4. This is not because the subject is unimportant, but rather because the subject is too important to be relegated to the kind of superficial discussion we could accord it while doing justice to the rest of the physics governing the fluid envelopes of planets. This chapter provides a glimpse at what the reader has been missing. It highlights what the reader needs to keep in mind when learning atmosphere/ocean fluid dynamics, and, for the student who has already acquired some familiarity with that subject, connects fluid mechanical effects with the key planetary climate phenomena that have been the subject of this book. It is, in essence, a sampler of some of the many ways that large-scale fluid dynamics affects planetary climate.
This being the final chapter (for now) of a long journey, we will also take stock of how well we have done at coming to an understanding of the Big Questions introduced in Chapter 1. We wrap up with a reminder of the great breadth of largely unexplored problems the reader is already equipped to take on. The universe of problems becomes all the richer once planetary fluid dynamics is brought into the picture.