10 February 2010

Closing the Strait of Hormuz – An Ace up the Sleeve or an Own Goal?

Leighton G. Luke Manager FDI Research Programme

Summary

As the diplomatic manoeuvring surrounding the Iranian Government’s nuclear programme continues, so too does the possibility that might attempt to interdict traffic passing through the Strait of Hormuz or even to close the waterway entirely. The Strait of Hormuz is a key energy shipping lane and the planet’s most crucial chokepoint. Such a move would have profoundly negative consequences, not just for the hydrocarbon exporters of the , but also for the global economy and Iran itself.

Analysis

The Strait of Hormuz is the most crucial of all the world’s chokepoints. It links the otherwise enclosed waters of the Persian Gulf with the and the Indian Ocean via the Gulf of , with the Islamic Republic of Iran occupying its northern shores and the Sultanate of Oman’s to the south. The two 3.2 kilometre wide shipping lanes (one Source: Adapted from Perry -Castañeda Library Map Collection, University of , Austin. lane in each direction), separated by a buffer zone also 3.2 kilometres in width, are located just inside Omani territorial waters. Approximately 32 kilometres across at its narrowest point, the Strait is the conduit through which the majority of the ’s hydrocarbons exports must pass before they can

power the global economy. Ninety per cent of the Persian Gulf’s oil exports, more than 40 per cent of globally traded sea-borne oil (between 16.5 and 17 million barrels per day (bbl/d)), and the liquefied exports from LNG giant Qatar, transit this confined waterway. Keeping the Strait of Hormuz open is therefore vital not only to regional producers and Western energy consumers such as the , , Japan and , but to the world economy in general.

Naval Mines Likely Method

The only state likely to attempt to close the Strait of Hormuz is Iran; the best method available for it to do so is the use of naval mines. Indeed, Iran has threatened shipping in the Persian Gulf on a number of occasions and has already used mines to do so. During the so- called “” phase of the 1980-88 Iran- War, Iran laid a number of naval mines in the Persian Gulf, one of which struck the USS Samuel B. Roberts , a patrolling United States guided , resulting in the death of over 30 crewmembers. While the incident did not sink the vessel, nor did it take place in the Strait of Hormuz itself, it nevertheless demonstrated the vulnerability of shipping to mine damage. Despite advances in mine clearing and countermeasures, it is a vulnerability which still remains.

With the obvious discrepancies between the Iranian and US military forces and the relative ease with which the US could destroy even the mobile batteries of anti-ship installed along the Iranian shoreline, Iran’s ability to close or, at least, threaten, the Strait of Hormuz hinges on its capacity to deploy mines.

Hormuz Closure as a Negotiating Tool

While it is not the purpose of this paper to delve deeply into the exact circumstances under which Iran may feel compelled to attempt to close the Strait of Hormuz, i