Emerging Threats to Underwater Cultural Heritage

Learn about the most relevant threats to UCH and ICUCH’s role in advocacting for them. 

This advocacy project focuses on the environmental challenges facing UCH in a time of rapid climate change. It outlines the major risks linked to rising sea levels, ocean acidification, and extreme weather events, and offers strategies to mitigate and adapt to these impacts in underwater cultural heritage sites.

 

Underwater cultural heritage is uniquely vulnerable to environmental changes accelerated by climate change. Rising sea levels are submerging coastal archaeological sites, while ocean acidification threatens to erode fragile artefacts and ecosystems that help stabilise wreck sites. Increasingly intense typhoons and storms are physically damaging submerged structures and scattering artefacts across the seabed. 

 

The Emerging Environmental Threats advocacy project calls for urgent heritage-led adaptation strategies. Risk assessment frameworks must include climate variables and long-term monitoring, ensuring that decision-makers understand the vulnerability of submerged sites. The project further highlights the importance of integrating Indigenous and local knowledge, which provides deep insights into environmental cycles and adaptive strategies. It advocates for regional cooperation, investment in predictive modelling, and heritage-inclusive climate policies.

This advocacy project examines the expanding industrial footprint in marine spaces, such as renewable energy, seabed mining, and infrastructure, and its implications for the safeguarding of underwater cultural heritage.

 

Industrial activity in the oceans is intensifying, and with it, risks to UCH are multiplying. Offshore renewable energy projects, seabed mining operations, and large-scale infrastructure such as ports and cables all affect seabed environments where heritage sites are located. In many jurisdictions, heritage assessments are insufficient or conducted late in project cycles, leaving sites vulnerable to destruction.

 

The Industrial and Economic Pressures advocacy project calls for stronger, mandatory cultural heritage impact assessments within Environmental Impact Assessment processes, ensuring that archaeological surveys are carried out before, during, and after industrial projects. It stresses the need for interdisciplinary collaboration, bringing together developers, heritage professionals, and local communities. Importantly, it underscores that heritage should not be framed as an obstacle to development but as an asset contributing to sustainable marine management.

Why deep-sea mining matters?

Deep-sea mining (DSM) poses serious, often irreversible risks to underwater cultural heritage (UCH), including shipwrecks, archaeological sites and artefact contexts, through mechanical destruction, sediment plumes, chemical alteration, and acoustic disturbance. The informational value of UCH lies in its archaeological context, which DSM irreversibly disrupts.

 

Current regulation of DSM

The relevant legal framework combines the United Nations Convention on the Law of the Sea (UNCLOS), the 2001 UNESCO Convention on the Protection of the Underwater Cultural Heritage (2001 Convention), and the International Seabed Authority’s (ISA) Mining Code. 

While article 303(1) UNCLOS generally requires States to protect objects of archaeological and historical nature at sea and to cooperate internationally, article 149 refers explicitly to the Area (the deep sea zone beyond national jurisdiction) and mandates that “objects of an archaeological and historical nature found in the Area shall be preserved or disposed of for the benefit of mankind as a whole.” However, reference in the same proviso to preferential rights of different stakeholders (States, private persons) raises serious doubts about the effectiveness of such a rule.

 

The 2001 UNESCO Convention establishes a modus operandi among its State parties when involved in deep sea mining. Through a system of notification and cooperation among States with a declared interest in the UCH located in the Area, the Convention creates a protective framework based on the principles of in situ preservation in its archaeological and natural context as the first option (that is, precaution), prohibition of commercial exploitation of UCH, and a set of scientific operational rules included in its Annex for activities directed at the UCH locates in the Area.

 

But these principles are not yet clearly endorsed by mining regulations at ISA. Current ISA draft exploitation regulations lack comprehensive UCH safeguards, prompting calls for a precautionary moratorium. Best practice requires integrating UCH-specific provisions into the Mining Code, strengthening national measures, and ensuring in situ preservation.

 

ISA Draft Regulations and Heritage Gaps

However, there is a fundamental problem regarding deep sea mining and the protection of UCH: while mining is exclusively regulated by ISA through its Mining Code, ISA has no such competences on UCH and its preservation. Already adopted Regulation on Exploration and the Draft Regulation on Exploitation Regulations include environmental assessments but lack binding, detailed UCH safeguards. These instruments establish obligations but require operationalisation through ISA rules and national measures.

 

However, they lack explicit, binding provisions for UCH comparable to the UNESCO Convention’s Annex. References to cultural heritage remain limited and non-prescriptive. Negotiations are politically contested, with many States and civil society actors advocating a moratorium until protective safeguards are embedded.

 

In 2025, a wide-ranging proposal by Spain (DR35) trying to address all these concerns were generally accepted by the ISA working groups and, with some reservations, by most State members at ISA. ICUCH explicitly supported Spain since the ISA Council meeting of July 2024, when DR35 was presented.

 

Recommended Measures

Like other States and most NGOs participating in the ISA negotiations (including IUCN), ICUCH supports the adoption of an immediate moratorium or precautionary pause on DSM in the Area, consistent with the precautionary principle, until independent science and binding UCH standards are established.

 

ICUCH will continue to collaborate with like-minded States members on the integration of UCH-specific rules into the ISA Mining Code, including: (a) mandatory heritage impact assessments; (b) baseline archaeological surveys; (c) prohibition of commercial exploitation of UCH; (d) mandatory documentation and reporting; and (e) designation of no-mining heritage zones. To this, ICUCH is in the best position to cooperate as expert with the ISA Legal and Technical Committee on UCH, as well as advisor on the national implementation of UNESCO 2001 standards, ensuring contractors comply with UCH obligations.

 

UCH, especially but not exclusively those that sank during the world wars, may be the last resting place of those on board when the vessel sank and thus akin to a grave – a ‘maritime war grave’. There is, however, no concept in international law of a ‘maritime war grave’, and no State has such a concept in its national law.

 

When UCH have been found, investigated, and excavations have taken place, ethical standards of archaeological practice that set out best practice for dealing with human remains have usually applied. In unregulated salvage or pillage of UCH these ethical archaeological standards are not necessarily applied, and in many cases, cannot be enforced as they are merely standards of good practice.

 

The management of UCH with human remains and especially those that may be considered a maritime ‘war grave’ therefore continues to require balancing the needs for the protection of the historical and archaeological importance of the site with its venerated status. How these remains are to be treated, or how those who perished when a ship foundered, is a difficult and emotive issue as cultural attitudes differ making it difficult to manage this when different nationalities died on the same ship, or a wreck of one State lies in the waters of another.