1. In its Resolution 73/333 entitled “Follow-up to the report of the ad hoc open-ended working group established pursuant the General Assembly resolution 72/277 [Towards a Global Pact for the Environment]”, the General Assembly of the United Nations recognizes “existing obligations and commitments under international environmental law” (recital 4). It endorses all the Recommendations of the ad hoc open-ended working group, as set out in the annex to Resolution 73/333 (para. 1). One of the objectives guiding the Recommendations is to “uphold the respective obligations and commitments under international environmental law…” (Recommendations, para. 2). Furthermore, one of the substantive Recommendations is to “recognize the role of discussions on principles of international environmental law in enhancing the implementation of international environmental law” (Recommendations, para. 8). The draft Political Declaration of 11 October 2021 uses the same wording as recital 4 of the Resolution 73/333 and recognizes “the importance of their effective implementation [i.e. of existing obligations and commitments] in ensuring an environmentally sustainable future for our planet and addressing urgent social, economic and environmental challenges, …”, as well as “the essential role of the rule of law and effective governance to ensure compliance with environmental law, …” (draft Political Declaration, recitals 7 and 8). It also calls upon “Member States and Members of Specialized Agencies to recognize and incorporate principles of international environmental law into their national legal systems and highlight the support that can be provided through the Montevideo Programme V, and … commit to cooperate to build and support the capacity of courts and tribunals at all levels to give full effect to principles of international environmental law for fostering environmental rule of law” (draft Political Declaration, para. 10).
The International Court of Justice (ICJ) had the occasion in certain cases to underline some of these existing obligations and commitments. To mention but one well-known example: in its judgment in the cases “Certain Activities carried out by Nicaragua in the Border Area” and “Construction of a Road in Costa Rica along the San Juan River” (16 December 2015), the ICJ held that in order “to fulfil its obligation to exercise due diligence in preventing significant transboundary environmental harm, a State must, before embarking on an activity having the potential adversely to affect the environment of another State, ascertain if there is a risk of significant transboundary harm, which would trigger the requirement to carry out an environmental impact assessment”. “If the environmental impact assessment confirms that there is a risk of significant transboundary harm, the State planning to undertake the activity is required, in conformity with its due diligence obligation, to notify and consult in good faith with the potentially affected State, where that is necessary to determine the appropriate measures to prevent or mitigate that risk” (para. 104, para. 153, para. 168). In this context, the ICJ had also the opportunity to examine provisions of international environmental agreements, in particular articles 3 and 5 of the Ramsar Wetlands Convention and article 14 of the Convention on Biological Diversity (para. 109 and 110, para. 163 and 164).
Nearly fifty years have passed since the 1972 Stockholm Conference and the Declaration on the Human Environment. Fifty years of important legal developments. International environmental law has evolved into a complex and elaborate, specific branch of international law, and its core obligations are part of the main rules of international law. But it was not until the ICJ issued its Advisory Opinion concerning the “Legality of the Threat or Use of Nuclear Weapons” (8th of July 1996) and its judgment in the case concerning “the Gabcikovo-Nagymaros Project” (25th of September 1997) that the remaining shadow of doubt about the existence of a binding corpus of international environmental obligations was finally removed.