In April 2007 the United Nations Security Council (UNSC) held an open debate on climate change, energy and security. While this might at first glance seem to have confirmed the successful securitization of climate change at the international level, this is far from the case. There is a politics of securitization. Both critics and advocates of referring to climate change as a security-as opposed to solely an environmental-issue acknowledge that one objective of doing so is to raise the profile of the issue and the resources and expertise that governments allocate to it. At an international level there are, however, other implications, including that of the relevant institution and body of international law that can be invoked in addressing the issue. This article identifies three conceptualizations of climate change as a security threat. It does not aim to evaluate the appropriateness of those conceptualizations, nor to construct a normative argument in favour of one or the other. Rather, it outlines the international law ramifications of each and how those ramifications might impact on the international politics of climate change were that conceptualization to become widely accepted. It draws on this analysis to illuminate why it is that climate change has not yet been, and is unlikely to be, fully securitized in world politics.