Canal Istanbul project casts doubts on Montreux Convention

Canal Istanbul, the 50-km waterway planned by Turkey’s ruling Justice and Development Party as one of its trademark megaprojects, has raised significant objections over its potentially devastating impact on the city’s ecology.

It could have an equally profound effect on Turkey’s security and the international agreements that have governed passage through the Bosporus Straits since 1936.

This is no ordinary politician’s vanity project. The cost of building it alone – estimated at between $15 billion and $20 billion – already sets it apart, and that does not take into account the additional costs likely to be raised by the geographic damage it could wreak.

For one thing, the water in the Black Sea is less salty than the Mediterranean and Marmara seas, and so flows in their direction close to the water’s surface, while the water going in the other direction moves in an undercurrent.

Ecosystems have built up around these flows of water over millennia. They are already under threat from the rising levels of pollution. It is not more investment or new initiatives that the area needs, but measures to reduce the pollution.

Ecologists and earth scientists say the construction of a giant manmade waterway would turn the delicate ecological balance in the area upside down, increasing the flow of the surface currents from the Black Sea and drawing industrial waste from the River Danube into the Marmara Sea.

At the same time, they say, the canal could decrease the undercurrents into the Black Sea, which could eventually poison organisms there.

Once the canal is completed, Istanbul would be surrounded by water on all sides, and critics say this could prove disastrous for a city that lies on a geological fault line. Besides the increased risk if an earthquake strikes the city, some say it could also create defence vulnerabilities for Turkey’s largest and most productive city.

At the same time, the creation of a new passage linking the Black Sea to the Marmara Sea raises significant questions of international law, since the Bosporus strait is considered a crucial strategic waterway by many neighbouring states, particularly those with coastlines on the Black Sea.

Since 1936, the straits have been subject to the Montreux Convention, a regime that places the Bosporus and Dardanelles fully under Turkish control, but also guarantees the passage of civilian vessels in peacetime.

The agreement has generally been regarded as a significant gain for Turkey, since it effectively confirmed its control of the Bosporus, removing international oversight and allowing Ankara to remilitarise the straits while also placing limits on the passage of non-Black Sea countries’ naval vessels.

The Montreux Convention deals with the Bosporus Strait, the Marmara Sea and the Dardanelles Strait as a whole, listing in great detail the regime for commercial and naval vessels to cross these seas during wartime and peace.

It states that commercial vessels have complete freedom to cross the Bosporus in times of peace. Turkish authorities only have the authority to conduct health checks on the ships according to international health regulations, and passing vessels are only obliged to pay limited taxes and related expenses. During time of war, Turkey maintains the authority to limit these freedoms for commercial vessels only under certain circumstances.

Meanwhile, certain low-displacement classes of naval vessel are allowed to cross the strait without paying any taxes or other dues in times of peace.

However, countries without a coastline on the Black Sea may not send their warships across the straits without giving Turkey notice between eight and 15 days in advance. Moreover, their submarines and ships of the line under ordinary circumstances are barred from crossing the straits, and the convention effectively bans all aircraft carriers from crossing, including those from Black Sea states.

The total number of foreign warships that is allowed on the straits at one time is nine, and they are not allowed to have a tonnage that exceeds 15,000 tons.

In wartime, if Turkey has not taken sides in the conflict, then the convention gives the country the right to deny passage through the straits of combatant vessels, with only a few exceptions.

In other words, the convention gives Turkey a privileged position in the management of the straits. But it also grants commercial vessels the right of free passage through them in most circumstances.

This complicates the case for Canal Istanbul. Its proponents say that the high traffic passing through the Bosporus makes a new route necessary to reduce the risk of accidents. But since commercial vessels can already pass the straits for free, and the canal would almost certainly require tolls to justify the cost of building it, the Turkish government would find it extremely difficult to force them to change their current routes.

If the government follows its established practice of granting private firms that undertake public infrastructure projects an income guaranteed by the Treasury, this would add another huge burden to the country.

At the same time, a new waterway could raise objections from Black Sea states since it could call into question the Montreux Convention’s continued validity. Of primary concern would be whether the convention’s restrictions on non-Black Sea states still apply, or whether Turkey can govern the canal as it pleases.

This would lead to serious disputes with Turkey’s nearest neighbours, and could make the Black Sea a focal point for conflicts.


The opinions expressed in this column are those of the author and do not necessarily reflect those of Ahval.