This chapter, Climate Security Intelligence, introduces climate security intelligence as a knowledge discipline created from the intersection of climate change and national security. Most who have written about climate security have done so from an outcome perspective, i.e., the negative actions or inactions that create instability, such as societal conflict, food insecurity, agricultural and water shortages, etc. The book’s contribution comes from a different perspective: from organizational and process lenses that are applicable to any organization having an intelligence function—whether governmental, public, or private—that possesses the responsibility of warning about and protecting climate security. Using this perspective, climate security intelligence is introduced. Discussed are what intelligence is and its definition, the early efforts of environmental intelligence and its subdiscipline of disaster intelligence, the definition of climate security intelligence, what the literature says about climate security intelligence, and the different nomenclature of climate security intelligence and climate intelligence. The relationship between climate change, climate security, and climate security intelligence is articulated. An initial theory of climate security intelligence is presented.