This book surveys the global researches on environment through the prism of security studies. ‘Environmental Security and Sustainable Development’ has featured prominently in the discourse of academic international relations and real-world international relations among the countries. Not everyone, though, is convinced of the merits of treating ecological concerns as matters of political emergency, and environmental security as a concept remains highly contested. In addition, environmental security is inconsistently interpreted by its advocates since ‘security’, in terms of its meaning and the means of achieving it, is viewed differently by different political actors and thinkers, as a consequence of this, the academic literature on environmental security that has evolved over the past few decades has tended to polarize rather than synthesize into clearer thinking. This book seeks to provide some much-needed clarity to thinking about environmental security by presenting the debate on the appropriateness and meaning of this concept in a systematic and accessible format.