Maritime claims and competition for resources often disregard conservation and sustainability, undermining cooperation on environmental protection. The South China Sea presents a case where the rule of law is failing to protect the marine environment. Overlapping maritime claims and open confrontation for control over areas of the SCS culminated in the PCA South China Sea Arbitration. The requirement to cooperate under UNCLOS is at fundamental odds with the competition for natural resources. Even UNCLOS’s due regard mechanism which ensures a balance of rights and interests among coastal and non-coastal States in their uses of EEZs presumes peaceful co-existence and willingness to cooperate. A binding ASEAN Code of Conduct is a possible avenue to enforce a moratorium over the claims and drive urgent cooperation based on Chapter XII to reverse the fast-deteriorating marine environment. The rule of law is relevant to conservation cooperation in the South China Sea.

The protection of marine environment assumes a special place under UNCLOS. Part XII provides for general obligations to protect and preserve the environment as well as more specific provisions concerning the prevention, reduction and control of marine pollution, including those relating to different sources of pollution. At the same time, Part XII is intended to provide a general framework for the protection of the marine environment. This framework nature is demonstrated not only by the existence of many generally-worded provisions and open-ended obligations which need to be further elaborated but also in the existence of numerous reference to external rules and standards, international organisations and regional arrangements. This chapter examines the contribution of UNCLOS tribunals to clarifying the scope and content of the general obligation to protect and preserve the marine environment before moving to discussing the extent to which UNCLOS tribunals have shed light on the normative content of three key environmental obligations and principles in the context of the marine environment.

There is a pressing need to strengthen systemic integration and mutually supportive interpretation of norms and institutional coordination between the UNECE environmental agreements with a view to understanding their collective contribution to clarifying and further developing international water, environmental and general international law. This chapter identifies the contribution of the UNECE regime to established ‘central or cornerstone rules and principles’ of international water law, including the due diligence rule to avoid or mitigate transboundary harm, the duty to cooperate, the principle of equitable and reasonable use and transboundary environmental impact assessments (EIAs). Key findings demonstrate that these rules and principles are defined in greater detail in the UNECE treaties compared to global treaties, which fills gaps in international law. For example, the UNECE clarifies international law regarding transboundary EIAs by providing criteria to identify what level of risk triggers the obligation to conduct an EIA and compulsory minimum content of EIAs. The UNECE regime also clarifies the effect of applying general principles, like the precautionary and polluter pays principles to the ‘no harm’ rule which strengthens these obligations. The strengths and weaknesses of UNECE’s contribution to developing reporting mechanisms for the Sustainable Development Goals, especially SDG 6 on water, are discussed.

This chapter provides an understanding of where international law is at (including customary international law, treaty and case law) in terms of its achievements and shortcomings regarding cooperation over environmental protection and use of transboundary freshwater ecosystems. This work provides a basis for critical analysis over the proceeding book chapters, in relation to the value added by the UNECE. The chapter lays the foundations for determining the UNECE regime’s relationship to international water law, international environmental law and general international law. It explores the role of international courts and the international law commission in interpreting outdated water treaties and bringing their standards of environmental protection closer to contemporary scientific understandings and the more progressive multilateral environmental agreements in accordance with the principle of systemic integration. It also explores instances where Courts have arguably has not gone far enough, leaving gaps in understanding. Unlike Courts, pan-regional or basin treaties and their river basin commissions can develop and interpret rules and principles of international water law on a continual and comprehensive basis and provide the institutional framework which supports implementation and compliance with international water law. This hypothesis, on the added value of the UNECE water regime, is tested over the proceeding chapters.

Tracing the background and origins of common concern of humankind, this chapter elaborates the legal framework and normative components of a future principle of Common Concern of Humankind. While its contours have remained vague and undetermined so far, we suggest that a future principle could emerge in a process of claims and responses, consisting of essentially three dimensions. Problems actually or potentially posing a threat to international peace and stability - and thus in need to be addressed - entail obligations to consult and cooperate, beyond current disciplines of general public international law. It entails obligations to implement international obligations and commitments, in addition to domestic law which in the field, may deploy extraterritorial effects in addressing the shared problem at hand. Finally, the principle obliges states to act and take countermeasures, subject to proportionality, in response to free-riding and evasive states. The principle of Common Concern is not limited to international law, but may also deploy comparable effects within states and federations in addressing pressing shared problems. It has the potential to become an important building block of transnational federalism and multi-level governance and to assist restructuring different areas of public international law seeking greater cooperation and commitments in addressing pressing and shared regulatory needs.