This chapter explores the implications of considering environmental degradation as a security threat through highlighting the ways in which security can be deﬁ ned when related to the environment. First, the chapter maps out the rationale for narrating environmental degradation as a security issue. Second, the chapter looks at the relationship between environmental concerns and security when we consider environmental degradation as a catalyst for conﬂ ict and violence both between and within states. Third, the chapter looks at how wider deﬁ nitions of security (e.g. human security) may be more useful when we consider environmental problems. Finally, the chapter outlines some of the critiques of securitising the environment.