Would it be possible to make a subtle shift in emphasis, which would give you the opportunity to talk about some possible theoretical bases for climate network theory.

Perhaps you could survey the existing applications in climate network theory, find some common themes, and abstract from them. Any kind of abstraction or generalization could lead you towards grounds that you are more familiar with, so at least part of your talk could involve sharing ideas from network theory which could potentially be relevant in the context of climate networks.