This paper focuses on the analysis of the multilateral regime of climate change from the perspective of the regimental complex. It examines the role of the BASIC countries in the signing of the new climate agreement in Paris and its relationship with traditional powers like the United States and the European Union. The role of the BASIC countries has been crucial to close a new deal, and in exchange for that power, the group has accepted two conditions: a bottom-up agreement and nationally determined contributions as a vehicle for climate action. Similarly, the diffusion of power in the international system means that although the triangle formed by the BASIC-EU-US has been critical to achieving a new climate agreement, other actors also played an important role in the negotiation process of COP 21.