NOT so long ago, it seemed that international moves to combat global warming could lead to shipping being regulated in regards to emissions by an agency other than the International Maritime Organization (IMO).
A massive lobbying effort followed, to ensure that this United Nations agency, which regulates most aspects of the international shipping industry, was given the responsibility of taking shipping towards a zero carbon dioxide emissions future.
Fingers crossed, this appears to have worked, though there is no room for complacency. Much depends now how effective the planned measures are seen to be.
A similar discussion is now underway to develop a legally binding international instrument on the conservation and sustainable use of marine Biological diversity in areas Beyond National Jurisdiction (BBNJ). In everyday language, this covers living things in the high seas, which cover more than 70 per cent of this planet.
A UN oceans conference now going on in New York aims to take the first steps towards BBNJ.
The IMO is taking part in the event, and putting itself forward as the regulatory authority for BBNJ as far as the operation of commercial shipping is concerned. Its representative Fredrik Haag is arguing that ships plying their trade across the world's oceans are already subject to stringent environmental, safety and security rules governing their voyages - rules developed by the IMO.
The shipping industry is giving strong backing to the IMO on this.
IMO regulations are enforced through a well-established system of flag, coastal and port state control. Many IMO measures already actively contribute to the conservation of marine biological diversity in areas beyond national jurisdiction; these include the International Convention for the Prevention of Pollution by ships (MARPOL) and the International Ballast Water Management Convention, which aims to prevent the transfer of potentially invasive aquatic species, as well as the London Convention and Protocol regulating the dumping of wastes at sea.
IMO has adopted numerous protective measures, which ships must adhere to, both in and outside designated sensitive sea areas (PSSAs) and in special areas and emission control areas. These include strict rules on operational discharges, areas to be avoided and those aimed at keeping shipping away from whales' breeding grounds, for example.
The IMO's Polar Code is mandatory for ships operating in the Arctic and Antarctic; it has also issued guidance on protecting marine life from underwater ship noise.
On the sidelines of an event organised by the IMO and a few other parties held at the UN headquarters last week, Mr Haag presented the IMO's regulatory regime and its relevance to BBNJ.
At the same event, Esben Poulsson, chairman of the International Chamber of Shipping (ICS), highlighted the need to ensure that the new UN initiative on BBNJ does not unintentionally hurt the effective future governance of global shipping, interfere with principles such as freedom of navigation or in any way cut across the work of IMO.
He stressed: "As a result of the global rules already provided by the IMO, ships are not operating in a regulatory vacuum. A ship-owner's activities are never beyond national jurisdiction, even on the high seas."
The ICS has thrown its full support behind the objectives of the UN negotiations and the critical need to provide environmental protection for the ocean from activities such as fishing and seabed mining.
But it points out that these activities, unlike commercial shipping, do not enjoy a comprehensive framework of global regulation such as that which has been developed over a period of 50 years by the IMO and its 174 member states.
The global ship-owners' body says the IMO regulatory framework already governs virtually every aspect of maritime environmental protection and is genuinely implemented on a worldwide basis. It includes a sophisticated mechanism for Port State Control enforcement, which means that ships are inspected for full compliance with global IMO standards, regardless of the flag state of the ship.
A new UN instrument is likely to lead to area-based management tools such as Marine Protected Areas (MPAs) being developed for the high seas. The ICS wants any measures that might apply to shipping in such MPAs to be decided by IMO. This could include, for example, special navigational measures to protect whales.
"IMO should always be the lead organisation for developing environmental rules that may affect international shipping" said Mr Poulsson. "The IMO's jurisdiction is broad and extends already to shipping activity in areas beyond national jurisdiction."
It is important that the IMO retain control of matters that affect the safe operation of merchant ships and their impact on the marine environment.
But we should keep in mind the wider picture. Getting an international agreement on how to manage sustainably the exploitation of the marine environment in the high seas is vital to the future health of the planet. Anybody who has seen the vast fishing fleets operating way offshore should realise that this is an activity that urgently needs monitoring and regulating.
The IMO already has a role in fishing vessel safety. The Cape Town Agreement was adopted at an international conference held under IMO auspices in South Africa in 2012, as a means to bring into effect the provisions of the 1977 Torremolinos International Convention for the Safety of Fishing Vessels, which was later modified by the 1993 Torremolinos Protocol.
However, movement to towards ratification of this agreement has been painfully slow. Perhaps this does not bode well for an effective BBNJ treaty. On the other hand, much more political pressure is likely to be put on governments to act to save the marine environment than to protect the lives of fishermen.