By: Alex Marsh

Extended continental shelf (ECS) claims have become increasingly important to coastal states due to emerging technology and a changing climate that has opened new possibilities for resource extraction, but what exactly are these far out maritime features?

“Normal” continental shelf claims as defined in Article 76 of the 1982 United Nations Convention on the Law of the Sea (UNCLOS) are “the seabed and subsoil of the submarine areas that extend beyond [a coastal state’s] territorial sea throughout the natural prolongation of its land territory to the outer edge of the continental margin, or to a distance of 200 nautical miles from the baselines from which the breadth of the territorial sea is measured…” In other words, the continental shelf is the natural extension of a state’s landmass into the ocean, at a maximum distance of 200 nautical miles (M) from a state’s claimed baselines.

But there are many areas where the geography of the continental shelf extends beyond 200 M, and in these places, coastal states can submit an extended continental shelf claim for an area up to 350 nautical miles from their baselines if it can be proven that this area is still a natural extension of their land territory.

Continental shelf claims are valuable because of the rights they grant coastal states over the claimed area. Articles 77 and 81 of UNCLOS establish that a state entitled to an area of continental shelf retains the exclusive right to explore and exploit the natural resources located on or in the shelf. These rights extend to mineral/non-living resources as well as seabed organisms. Coastal states are not, however, granted sovereignty over the sea or airspace above a continental shelf entitlement.

If a state believes it is entitled to an area of continental shelf beyond 200 M, it will submit data and information supporting its claim to the Commission on the Limits of the Continental Shelf (CLCS), a UN body composed of scientific experts responsible for adjudicating extended continental shelf claims. After consideration of the submission, the CLCS will then issue a binding recommendation on the scientific validity of the state’s claim.

There are many scenarios where more than one state will lay claim to the same area of extended continental shelf. When this occurs, the states will submit their supporting data to the CLCS, who will then provide a recommendation on the validity of each state’s continental shelf claim. The CLCS does not, however, set the boundary between the two states but may only provide a recommendation on whether each state’s claim is scientifically valid. It is then up to the various claimants to negotiate an ECS boundary.

Coastal states have 10 years from the date they ratified UNCLOS to submit extended continental shelf claims. For example, Canada ratified UNCLOS in 2003, and needed to submit any extended continental shelf claims to the CLCS by 2013. A state may then later amend or supplement submissions. Canada deposited its initial ECS claims for the Atlantic Ocean in 2013 and added an area of Arctic Ocean ECS in 2019. States that are not signatories to UNCLOS, such as the United States, are unable to submit extended continental shelf claims to the CLCS, but they do still have ECS claims. The United States is currently working on its extended continental shelf claim.

Extended continental shelf claims involving only one state are typically non-controversial if they are deemed scientifically valid. For example, the area of high sea known as the “Peanut Hole” in the Sea of Okhotsk was declared part of the Russian continental shelf by the CLCS in 2014 without much fanfare.

Notable extended continental shelf claims in recent years have primarily involved areas of overlapping claims. Overlapping claims naturally receive more attention and can take far longer to resolve. Denmark (Faroe Islands), Norway (including Jan Mayen), and Iceland recently ratified agreements to delimit their extended continental shelf entitlements in an area of the Norwegian Sea known as the “Banana Hole.” All three states submitted their supporting information to the CLCS with the understanding that once it was confirmed that their claims were scientifically valid, they would establish boundaries according to a preliminary trilateral agreement negotiated in 2006 and made official in 2019 after the decision of the CLCS.

Another example of overlapping claims can be observed in the marine Ontong Java Plateau, located in the southern Pacific Ocean. Micronesia, Papua New Guinea, and the Solomon Islands all have overlapping continental shelf claims in the area. Since all three small island states believe they are entitled to a portion of the area, they decided to pool their time and resources to make a joint submission to the CLCS to establish the outer limits of their overlapping claim rather than submit competing claims for portions of the plateau. Once the CLCS establishes the outer limits of the “claimable” area, the area will belong to all three states jointly until they choose to begin trilateral negotiations to delimit boundaries.

Perhaps the most prominent area of overlapping ECS claim are those in the Arctic Ocean. As climate change makes the region more accessible to economic activity, arctic coastal states are acting with increased urgency to ensure their access to large deposits of natural resources underneath the melting icecap. Canada, Denmark, Norway, and Russia have all made overlapping claims in the region, and the United States is working towards publishing its ECS claim in the disputed waters.

The extended continental shelf is very much the next frontier of maritime boundary delimitation as technology improves to allow for coastal states to exploit the distant continental shelf resources, climate change makes portions of the ECS more accessible, and the global reliance on fossil fuels leads to interest in extracting hydrocarbon resources from novel locations.