3.3 Environmental impact assessment under the UNCLOS regime
As detailed earlier in this chapter, EIAs are an important tool across a range of industries. However, it has been highlighted that the holistic assessment of environmental impacts in shipping has remained limited, reflecting the sector’s highly international and mobile nature and the fact that its environmental regulation has largely developed reactively through protracted IMO standard‑setting processes(1)Jana Moldanová and others, ‘Framework for the environmental impact assessment of operational shipping’ (2021) 51(3) Ambio754–769, page 754. As environmental concerns related to shipping continue to develop, the importance of EIAs in the sector is likely to increase as a means of addressing its environmental footprint. This chapter explores the current role of EIA in shipping, focusing on the relevant international legal sources and corresponding obligations of flag States.
As established earlier, the shipping industry plays a central role in global trade through its facilitative role enabling the movement of goods across the oceans. At the same time, shipping activities pose a range of environmental risks, including ballast water discharge, underwater noise, and oil pollution. EIA can be an important tool to aid flag States in identifying environmental risks stemming from shipping activities and to develop appropriate mitigation measures, thereby contributing to the promotion of more sustainable maritime practices.
Earlier discussion in this thesis has demonstrated that UNCLOS requires States to assess the potential effects of activities under their jurisdiction or control where there are reasonable grounds for believing that such activities may cause substantial pollution of, or significant and harmful changes to, the marine environment, including pollution from vessels(2)Article 206 UNCLOS. For shipping activities, regulatory competence has primarily been exercised through the IMO, which has developed an extensive framework of technical standards aimed at preventing and controlling vessel‑source pollution. However, notwithstanding the breadth of instruments such as MARPOL, the IMO has not formulated a comprehensive EIA regime applicable to shipping as a sector. This regulatory gap has become increasingly relevant in light of the BBNJ Agreement, which operationalises UNCLOS obligations on EIAs for activities in ABNJ, while simultaneously requiring that its implementation do not undermine the mandates of relevant international sectoral bodies such as the IMO(3)Youna L B Lyons, EIAs under the BBNJ Agreement: Implications for Shipping (ACOPS, CIL‑NUS Workshop, 2024) slides 4–7 https://cil.nus.edu.sg/wp-content/uploads/2024/12/Session-4-EIA-and-BBNJ-Y-Lyons.pdf. The absence of a dedicated IMO EIA framework for shipping can raise the question as to whether existing IMO processes are sufficient to fulfil flag States’ due diligence obligations under Part XII of UNCLOS with respect to the environmental impacts of global shipping.
Before turning to the BBNJ Agreement in detail, it is useful to briefly address how its EIA provisions interact with existing international bodies, particularly the IMO. As discussed, the IMO has not developed a comprehensive EIA framework for shipping activities, beyond the general obligations binding its member States under UNCLOS. Under the VCLT, treaties neither impose obligations nor confer rights on third States without their consent, which also applies to international organizations(4)Article 34 VCLT. This does not, however, preclude treaty rules from becoming binding on third States when they attain the status of customary international law(5)Article 38 VCLT. In the present context, this means that while the BBNJ Agreement does not impose EIA procedures on the IMO as an institution, State Parties to the BBNJ Agreement remain bound by its EIA obligations and must act consistently with them when participating in IMO processes and decision-making(6)High Seas Alliance, ‘How could the EIA provisions of the BBNJ Agreement apply to activities and existing bodies’ (July 2021) https://www.highseasalliance.org/wp-content/uploads/2021/07/FINAL-How-would-the-EIA-provisions-of-the-BBNJ-Treaty-apply-in-practice-7.8.21.pdf accessed the 20.04.2026.