Canada-US Territorial Dispute in the Beaufort Sea

Again on the agenda under Canada's new Arctic Policy

This explainer was prepared for my course in Public International Law at uOttawa, and is best viewed in video format.

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Welcome to this brief explainer. My name is Craig Forcese and I teach international law, among other things, at the University of Ottawa.

In December 2024, Canada announced a new Arctic policy. As part of this policy, Canada launched in September 2024 negotiations with the United States to resolve the 2 states’ long-standing maritime boundary dispute in the Beaufort Sea.

This explainer will first describe basic territorial issues governed by the law of the sea. It will then explore the Beaufort Sea dispute.

Let’s start with basic concepts of territory in the law of the sea.

Under the United Nations Law of the Sea Convention, or UNCLOS, the international law of the sea divides maritime areas into zones, tied largely to distance from so-called baselines along the coast.

Here is a schematic from my co-authored international law textbook setting out the various ocean zones.

Here, we’ll focus on a subset of these zones.

First, the territorial sea extends 12 nautical miles from a coastal state's baseline, granting full sovereignty over waters, airspace, seabed, and subsoil. The baseline is usually the low water mark of the coast. For irregular coastlines, straight baselines can be drawn for clarity, as allowed under UNCLOS.

Within the territorial sea, states enjoy sovereignty. However, as a caveat, foreign states enjoy a right to innocent passage. This permits foreign ships a right to transit the territorial sea without entering internal waters, so long as they do no harm to the state's security, peace, or good order. Thus, activities like fishing or military exercises are prohibited.

However, innocent passage does not exist for the waters on the landward side of straight baselines. For these so-called internal waters, a state has full sovereignty, and no foreign ship can enter these waters without permission.

Moving further out to sea past the territorial sea, a contiguous zone extends to 24 nautical miles from the baseline. It gives coastal states limited enforcement rights, allowing them to prevent and punish violations of customs, fiscal, immigration, or sanitary laws that spillover within their territory. However, it does not grant anything close to sovereignty and coastal states must respect the freedom of navigation of foreign vessels.

More important in terms of jurisdiction and certain limited sovereign rights are the Exclusive Economic Zone and the continental shelf. The Exclusive Economic Zone, or EEZ, as defined by UNCLOS, grants coastal states extensive rights to manage and exploit natural resources up to 200 nautical miles from their baselines, including fishing, oil and gas exploration, and regulating artificial islands and marine research.

However, the EEZ does not confer complete sovereignty, as other states retain freedoms such as navigation, overflight, and laying submarine cables and pipelines. The ability of coastal states to regulate these rights is limited. It cannot negate these rights.

Coastal states also have obligations to protect the marine environment, prevent over-exploitation of resources, and ensure their optimum utilization.

The continental shelf refers to the submerged extension of a coastal state’s land, granting sovereign rights over seabed and subsoil resources. It typically extends at least 200 nautical miles from the baselines, and under certain conditions, it can reach up to 350 nautical miles. Coastal states have exclusive rights to explore and exploit non-living resources and sedentary species, while the water column above remains subject to international navigation laws.

Both the EEZ and continental shelf are crucial for coastal states, but their overlapping zones can lead to disputes. UNCLOS stipulates that such disputes should be resolved by agreement in accordance with international law.

Let’s now turn to the Beaufort Sea dispute between Canada and the United States.

As the 2024 Canadian Arctic policy notes, this disputed area is ocean north of the Yukon and Alaska and measures approximately 270,000 square kilometres. Both countries claim jurisdiction over the disputed region by way of differing legal interpretations of an 1825 treaty between Russia and Great Britain.

The Beaufort Sea is known to contain significant natural resources, primarily hydrocarbons (oil and gas), as well as living marine resources such as fish.

Traditionally, the dispute has concerned the delimitation of the territorial sea and the EEZ.

At the legal level, the Beaufort Sea dispute between Canada and the United States stems from differing interpretations of the 1825 Treaty of St. Petersburg, which defined the boundary between Russian and British territories at the 141st meridian "as far as the Frozen Ocean." Canada asserts this treaty establishes the maritime boundary along the 141st meridian extending north. In contrast, the U.S. argues that the treaty does not govern maritime boundaries and advocates for using the international law principle of equidistance. This method involves drawing a line equidistant from the coastlines of Alaska, the Yukon, and the Northwest Territories, which slant east-southeast, creating a wedge-shaped area of disputed territory to the east of the 141st meridian.

The dispute is further complicated by potential claims to the extended continental shelf beyond the 200-nautical-mile limit of the Exclusive Economic Zone. Seabed mapping suggests the continental shelves of both countries may overlap in this area, raising the possibility of conflicting claims far beyond the EEZ.

Interestingly, the equidistance principle could benefit Canada further north. The geography of the Queen Elizabeth Archipelago causes the equidistance line to trend westward in the high Arctic, potentially granting Canada a larger share of the extended continental shelf.

From: Coalter G. Lathrop, Esq. at Sovereign Geographic and reproduced in Lalonde et al.

Adding to the mix if one resorts to the equidistance method is the complexity of baseline use in the region. Canada employs a combination of normal and straight baselines, which can enclose irregular coastal features, resulting in a larger claimed maritime area. In contrast, the United States uses only normal, low water mark baselines, calculating a smaller maritime area.

Here, for instance, is an example of straight baseline use by Canada in the Beaufort Sea.

From: Bekker and Van De Poll

The equidistance line, a common method for maritime boundary delimitation, is determined by measuring equal distances from the baselines of both countries. As a result, the differing baseline approaches directly impact the location of the equidistance line and the extent of the overlapping claims.

Advances in mapping technology also play a role. Modern methods like LiDAR provide greater precision compared to older nautical charts, potentially affecting the accuracy of baseline determinations and the resulting boundary claims. These technical and geographical factors, combined with differing legal interpretations, underscore the challenges in resolving the Beaufort Sea dispute.

Further, political issues, of course, colour this dispute. Both Canada and the United States fear precedents that may weaken their positions in other disputes. Domestic pressures influence negotiations, with Canada prioritizing Indigenous rights, especially those of the Inuvialuit. Economic motivations, such as access to hydrocarbons, amplify the stakes. Climate change and geopolitical instability, including Russia’s actions in the region, add new urgency.

It remains to be seen, therefore, how this dispute will be resolved.

Thank you for your interest in this explainer.

References:

Baker, James S & Michael Byers (2012). Crossed Lines: The Curious Case of the Beaufort Sea Maritime Boundary Dispute, Ocean Development & International Law, 43:1, 70-95. https://doi.org/10.1080/00908320.2012.647509

Bekker, P., & van de Poll, R. (2020). Unlocking the Arctic’s Resources Equitably: Using a Law-and-Science Approach to Fix the Beaufort Sea Boundary. The International Journal of Marine and Coastal Law, 35(2), 163–200. https://doi.org/10.1163/15718085-23441076

Lalonde, Suzanne & P. Whitney Lackenbauer (2024) Moving Beyond Benign Neglect: The Beaufort Sea Dispute and the Benefits of Compromise Solutions between Salt Water Neighbors, An Essay in Honor of Ted L. McDorman, Ocean Development & International Law, 55:4, 422-433. https://doi.org/10.1080/00908320.2024.2419030