Abstract
The research relevance is determined by the transformation of climate diplomacy into one of the key components of global governance in response to the worsening climate crisis. The study aimed to analyse the process of institutionalisation of climate diplomacy in the context of the transformation of the modern system of international relations. The methodology was based on an interdisciplinary approach that combined comparative, typological, interpretive, structural and functional methods, as well as the method of value analysis and political deconstruction. The study found that climate diplomacy has evolved from classical intergovernmental negotiations to a polycentric model of global governance with the active participation of non-state actors. The study identified the key stages of institutionalisation from the first environmental forums of the 1970s to the formation of a complex architecture of agreements and mechanisms such as the Kyoto Protocol and the Paris Agreement. The study analysed the structural and functional features of modern diplomacy, which includes negotiation, scientific and coordination subsystems operating both within and outside the United Nations. The study established that the regulatory framework of climate diplomacy is formed on the principles of global justice, inclusiveness and transparency, but its implementation is limited by political fragmentation, lack of funding and conflicting interests of actors. The study determined that institutional diffusion, regulatory hybridity and the use of digital technologies are becoming key trends in the development of this area. The theoretical analysis demonstrated that none of the existing paradigms, including institutionalism, constructivism or the concept of global governance, provides an exhaustive explanation of the phenomenon, but their combination creates a holistic picture. The study determined that climate diplomacy is a dynamic, multi-level process that both reflects and shapes the new logic of global cooperation. Its further institutionalisation depends on the ability to unite state and non-state actors around a common vision of climate justice. The practical significance of the study is determined by the formation of a conceptual framework for improving climate policy at the global and national levels