Since the first debate in the context of the United Nations Security Council (UNSC) in 2007 on whether climate change should be part of the UNSC agenda, the term “climate security” has gained greater attention. Today, several national and international security and defense strategies include the need to address climate change and urge international organizations to engage in climate security activities. This chapter explores these developments and introduces the reader to the research field, marked by different meanings, perceptions, and implications of climate security concepts, with a special focus on the Anthropocene. Informed by Earth System Sciences descriptions of the necessity to re-define security with respect to Planetary Boundaries and using critical security study approaches, the chapter provides a critical inquiry into limits, blind spots, and biases of the policy field of climate security and delves into the need for reconfigurating security in the context of the Anthropocene.