Regulating underwater noise: from international legal framework to local initiatives

The presence of sound in the ocean is undeniable: initially of natural origin (from rain, storms, marine life, or seismic activity), underwater noise now also includes sounds produced by human activities. Anthropogenic underwater noise has increased significantly since the 20th century due to the expansion of human activities at sea, such as maritime traffic, port operations, the gas and oil industry, renewable marine energy projects, and military activities, thereby intensifying human-induced pressure on marine life. Scientific literature documents the impacts of underwater noise on marine biodiversity and categorizes its effects on marine life by severity: behavioral changes, masking, temporary hearing loss, permanent hearing loss, and lethal injuries.

Underwater noise is an environmental issue that has recently garnered attention from the international community, with its intersectoral and cross-border nature highlighting both the complexity and the necessity of studying how it can be addressed legally. The importance of regulating activities that generate underwater noise is clear: such regulation can immediately reduce noise emissions from regulated activities, which is essential for achieving Sustainable Development Goal 14 of the 2030 Agenda for Sustainable Development adopted by the United Nations General Assembly in 2015.

To date, no international treaty explicitly addresses anthropogenic underwater noise. In the absence of specific regulation, underwater noise emissions are governed in accordance with the traditional summa divisio of international environmental law, both by treaties aimed at combating pollution and by those focused on nature protection through species and habitat conservation. Among the relevant international conventions are the United Nations Convention on the Law of the Sea, the Convention on Biological Diversity, and the Convention on the Conservation of Migratory Species, along with regional treaties such as the Barcelona Convention for the Protection of the Mediterranean Sea against Pollution and its protocols, and the Agreement on the Conservation of Cetaceans of the Black Sea, Mediterranean Sea, and contiguous Atlantic Area. The governing bodies of these conventions have adopted various soft law instruments aimed at regulating underwater noise emissions, including guidelines, objectives, and action plans. In this context, local initiatives to reduce underwater noise are multiplying, with the adoption of regulations and recommendations by managers of marine protected areas, as well as the establishment of incentive measures by port authorities that include recommendations and financial incentives aimed at shipowners.

This presentation will aim to outline, on one hand, the international legal framework applicable to this newly recognized form of pollution and, on the other, the local initiatives to regulate it, while highlighting the challenges and issues surrounding their evolution.