Towards a peremptory duty to curb greenhouse gas emissions?

Abstract

Is international law developing towards the recognition of a peremptory obligation for States and international organizations to stabilize anthropogenic greenhouse gas (“GHG”) emissions, so as to collectively attain a sustainable global average temperature increase? Do States have an obligation to cooperate and achieve this objective? Does such an obligation extend to non-State subjects? This Article explores the possibility that a new peremptory norm is progressively emerging in international law to contain global average temperature increase within sustainable limits, currently well below 2°C and possibly even 1.5°C above pre-industrial levels under the Paris Agreement, as well as its nature and scope. Arguably, the international and domestic practice of sovereign entities, civil society and NGOs is supportive, including the quasi-universal participation of States and international organizations in the UNFCCC and related instruments. Furthermore, the fundamental and shared nature of the atmosphere and climate, which cannot be adequately protected via conventions, compels thinking in terms of a goaloriented erga omnes duty akin to an obligation of result, triggering universal invocation of responsibility, sanctions, and enforcement. In light of the evolution of international law, the obligation to achieve sustainable anthropogenic GHG emissions could also address non-State natural and legal persons as both duty-bearers and right-holders, waiving immunity and triggering universal jurisdiction.