Myth Busting No 1 - Australia's Boundaries with neighbours and the Continental Shelf

The Australian newspaper, a News Corp publication, produced an unexpectedly positive editorial about the announcement on Monday of the Australian and Timor-Leste Government's intention to negotiate maritime boundaries. It also contained statements that need to be challenged. One promoted, perhaps unwittingly, the myth that Australia's boundaries with its neighbours are based on "the continental shelf principle". 

The editorial says:

"Australia argues that its maritime boundary should be drawn along its continental shelf, as it has always been. Timor maintains it should be an equidistant line between the two countries, a boundary that would give Dili most of the revenue flowing from the Timor Sea. Contemporary international law supports East Timor’s claim of equidistance. But the argument for it is complicated by consideration of our boundaries with Indonesia as well as Australia’s contention that the Timor Trough extending from close to the coastline of East Timor divides the two continental shelves. For decades Australia has based its maritime borders on the continental shelf principle endorsed by UNCLOS."

There are several parts of this quote that could be questioned but let's focus on the very last part which may lead people to incorrectly believe that Australia's borders with neighbours are based on "the continental shelf principle".

The fact is that almost all of Australia's maritime boundary delimitations with its neighbours are based on equidistance.  All of them in fact, if we are talking about the last four decades.

Keeping it simple, Australia has maritime boundaries with five of its seven maritime neighbours. They are New Zealand, Solomon Islands, France, Papua New Guinea and Indonesia. Boundaries are unresolved with Timor-Leste and Antarctica.

Australia's pre-eminent expert on international maritime delimitation, Professor Don Rothwell, presented a survey of the boundary treaty arrangements with all of our neighbours at a Monash University symposium last year. You can see a video of his presentation on the Monash webpage that recounts the event along with the slides used.

The table above simplifies what he says in the survey. Professor Rothwell nuanced his comments for each one so PNG was "predominantly equidistant", the Solomon Islands boundary "relies on principles of equidistance", the boundary with New Caledonia uses "a modified equidistant line" and the Indonesian arrangement in the Arafura Sea is "based on an equidistance line provision". He didn't specify with New Zealand but we know that it is based on equidistance. Alexander Downer confirmed this in his media release announcing the boundary delimitation in 2004 when he said, "The Treaty confirms the median line boundary between the overlapping EEZs (Exclusive Economic Zones)."

The only boundary between neighbours based on "the continental shelf" that Professor Rothwell refers to is the boundary with Indonesia in the Timor Sea.

It is true that the continental shelf is an important principle for maritime entitlements, particularly when there are no overlapping claims, but the facts are clear:

Except for one exceptional case (Indonesia), all of Australia's maritime boundaries with neighbours have been negotiated by principles of equidistance.

The negotiation with Timor-Leste should be based on equidistance, which even the conservative Australian newspaper recognises as "supported by contemporary international law."