Following on from last week’s graphs ^[1], I thought it would be worth looking at some of the consequences of the decline in western naval fleets. The graph below reprises last week’s data for the size of the United States Navy since 1960, but this time overlays it against the growth in the world’s commercial fleet over the same time.

Clearly the trends are in different directions—and dramatically so. In 1960 there were 45 commercial vessels in the world for every major combatant the USN could muster. Today the number is around 360. To be sure, not all of those commercial vessels are involved in activities that would bring them to the attention of the USN. The data set includes all vessels of 100 gross tons or more, and so includes many coastal and fishing vessels. But over half are cargo vessels ^[2] and are responsible for carrying most of the exported goods produced around the world.

Sources: USN fleet data ^[7] and Lloyd’s registry data via shipbuildinghistory.com ^[2]

There are at least two consequences of the simultaneous decline of western fleets and rapid growth of world’s commercial fleet. Firstly, the security market will begin to find solutions other than relying on the ‘free good’ provided by naval forces. It’s not surprising that private enterprise has identified a market niche, and is now moving to exploit it ^[8] using sophisticated commercial sensor and communication systems as well as their own vessels to assist in shepherding and convoying cargo vessels through dangerous waters.

The second consequence is that the global maritime commons will increasingly become a contested space. As the Center for a New American Security (CNAS) observed in a 2010 report ^[9] (PDF):

[In the future] protecting open access to the global commons will be in high demand, but the capacity of the US military to protect the commons will be challenged by new commitments and an increasingly diverse set of military threats. The status quo, in which the United States is the sole guarantor of the openness of the global commons and other states free ride, is unsustainable.

Their policy prescription is for the United States to engage its friends and allies in redoubling efforts to bed down international agreements and arrangements that protect the commons as we currently understand it. But it’s hard to see how the trends at work can be reconciled. The WWII tactic of herding vital shipping across the Atlantic in convoys ^[10], with the unsophisticated submarines of the day snapping at their heels, are long gone. Warships are fewer, vital shipping much more numerous and the stakes higher due to the economic interdependence all nations have thanks to globalisation. Finally, anti-access systems are becoming steadily more effective, making the task of protecting shipping more difficult and expensive—which is again likely to drive down the numbers of would-be escorts.

The net result is that I’m increasingly of the view that being able to secure shipping lanes for more than a tiny fraction of the world’s trade is fast becoming a thing of the past. The future is much more likely to see a number of nations possessing the capability to seriously disrupt global trade, and no one having the ability to effectively prevent it.

Andrew Davies is a senior analyst for defence capability at ASPI and executive editor of The Strategist.