Security studies in the 21st Century have broadened to encompass a variety of transnational phenomena newly defined as threats. Climate change is one of these phenomena. In theoretical terms, climate change is being securitized.

Climate change, in which man-made global warming is a major factor, is an internationally recognized phenomenon that is projected to produce dramatic, accelerating, and long-lasting human, economic, and political consequences with profound security implications. These will be most pronounced in places where the effects of climate change are greatest, particularly affecting weak states already especially vulnerable to environmental destabilization. National security establishments in the United States and elsewhere are hurriedly attempting to come to grips with climate change and how to respond to its strategic challenges.

This paper, in the context of securitization theory, human security, and sustainable security, discusses the phenomena of global warming and climate change, examines the destabilizing effects of climate change, describes how such effects are being perceived as transnational threats to security, and argues that securitization of climate change is necessary, timely, and irreversible.