Legal, Institutional and Judicial Developments in the Implementation of the 2015 Paris Agreement and an Assessment of Their Effectiveness during the Period (2020–2026)

Abstract

This study examines the legal, institutional, and judicial developments in the implementation of the 2015 Paris Agreement over the period 2020–2026, addressing the central research question of the extent to which these developments have enhanced the Agreement's effectiveness and facilitated a transition from procedural to substantive compliance capable of achieving its climate objectives. The study adopts an analytical approach to the provisions of the Paris Agreement and the decisions of the Conference of the Parties serving as the Meeting of the Parties (CMA), supplemented by descriptive and comparative methods, alongside an analysis of relevant international judicial trends. The research is organized into three chapters: the first examines the legal and institutional developments arising from successive Conferences of the Parties (from Glasgow 2021 through Belém 2025), foremost among them the evolution of the enhanced transparency framework and the conclusion of the first Global Stocktake in 2023; the second addresses the impact of the 2024 ITLOS and 2025 ICJ advisory opinions in broadening the legal basis of climate obligations; and the third evaluates the effectiveness of the Agreement's mechanisms through the distinction between procedural and substantive compliance. The study finds that the Paris Agreement has achieved measurable progress at the procedural level, reflected in the maturation of the transparency system, the Global Stocktake, and the progression principle governing Nationally Determined Contributions, whereas substantive compliance remains below the required threshold due to the persistent flexibility of national commitments, disparities in state capacity, and constrained means of implementation. The study further demonstrates that international judicial developments have not established a parallel regime to the Paris Agreement but have instead expanded the legal grounds available for assessing state climate conduct, through the due diligence standard and the integration of climate obligations with human rights and general international law. The principal scholarly contribution of this study lies in its analytical framework distinguishing procedural from substantive compliance, employed as a tool for measuring the actual gap between the procedures adopted and the climate outcomes achieved.