Due diligence in international environmental law as a general principle of law established within the framework of the international legal system

In recent years, the issue of holding states accountable for non-compliance with climate-related obligations has transcended academic debates, with an increasing number of appeals directed to international judicial and arbitral bodies, as well as requests for advisory opinions. Although the international legal framework establishing measures for the prevention of anthropogenic climate change has been largely developed, a pertinent question arises regarding the nature and scope of these international legal obligations. According to recent case law, one such obligation that has gained prominence is the duty of due diligence. In disputes concerning the compensation for transboundary environmental damage and in the issuance of advisory opinions, international courts and tribunals have increasingly referred to due diligence as a basis for attributing responsibility to states for harm caused by violations of international climate obligations. The aim of this article is to determine whether the obligation of due diligence has evolved into a general principle of law in the international legal system and to analyze the normative content that characterizes this international legal obligation.