Effects of climate change on the welfare of human and natural systems in developing countries will not be determined by the changes in climate alone; the sensitivity of these systems to the changes will also determine how impacts are experienced. Human systems are characterised by their adaptability, evidenced throughout human existence. However, climate change presents a new challenge, not only because of the expected rise in temperature and sea-level, but also due to current context of failure in addressing the causes of poverty adequately. As a result, policy supporting adaptation has recently been cast as a necessary strategy for responding to climate change and supporting development, making adaptation the focus of much scholarly and policy research. This thesis addresses this new adaptation discourse, by bringing together examinations of adaptation in theory, policy and practice. Thus, it traces adaptation within climate change and development discourses and assesses empirical evidence of adaptation in El Salvador, in order to inform both policy and theory. To this end, it explores the role of adaptation in the context of development, and questions the meaning of policy-driven adaptation. This work contributes a new interpretation of adaptation policy aimed at the UNFCCC negotiating community. It suggests an adaptation paradigm for sustainable development processes, where the objective is reduction of vulnerability and risk. This views adaptation as an existing and necessary practice that should be facilitated by development processes, rather than as the ultimate objective of explicit policies, which may not be incorporated into other planning and development processes. This allows non-climatic causes of risk, such as those identified in El Salvador, to be addressed, rather than circumvented. It requires a paradigm shift from the existing separation of discourses on climate change adaptation from risk and disaster discourses, in order to confront the root causes of vulnerability in an integrated and holistic manner. In turn, this will ensure sustainability of the adaptation process.