This article examines The African Union's Relationship with the United Nations: Complementarity, Subsidiarity, and Tension: Climate Change Dimensions with a focused emphasis on Mozambique within the field of Political Science. It is structured as a methodology article that organises the problem, the strongest verified scholarship, and the main analytical implications in a concise publication-ready format. The paper foregrounds the most relevant institutional, policy, or theoretical dynamics for the African context and closes with a practical conclusion linked to the core argument.