The U.S. Energy Information Administration (EIA) identifies six straits and canals as world oil transit chokepoints: Strait of Hormuz, Strait of Malacca, Suez Canal, Bosporus, Bab el-Mandab, and the Panama Canal. Given that tanker traffic accounts for nearly two thirds of the world's trade in oil, the security of shipping is of paramount importance. These six chokepoints are defined by their geographically constrained waterways and the high volume of oil tanker traffic. These bottlenecks are of critical importance to the shipping of oil and are, at least theoretically, highly susceptible to acts of piracy and shipping accidents.
The Strait of Malacca is widely considered the most vulnerable chokepoint, although it is perhaps the easiest to circumvent in the event of a disruption. The Strait is a narrow stretch of water nearly 500 miles long separating the Malaysian Peninsula and the Indonesian island of Sumatra. Approximately 12 million barrels of oil are shipped through this narrow thoroughfare each day. At its narrowest point, in Phillips Channel in the Singapore Strait, the channel is roughly 1.5 miles wide. Malacca is not only narrow, but also quite shallow - less than 22 meters in some spots. Dangers include collision, accidents, grounding (due to the shallow sea floor) and piracy. Over 50,000 vessels transit Malacca each year, probably because it is the shortest (and therefore cheapest) shipping route between Japan, South Korea, China and the oil fields of the Middle East. The nearby Straits of Makassar and Lombok provide alternate routes at a marginal cost increase — not the preferred routes during peacetime, but possible routes that would require little increase in cost during a disruption. In the event of a very severe disruption, ships could transit to East Asia by traveling all the way around Australia, remaining in the open ocean and adding only a few days of transit time.[i]
The Suez Canal and the Sumed pipeline connect the Red Sea with the Mediterranean Sea. Some 4.2 million barrels of oil transit the area each day with the bulk of product moving northbound from Saudi Arabia via the pipeline. Closure of the canal would divert tanker traffic around the Cape of Good Hope, substantially increasing transit time and driving up costs. The Suez Canal was blocked and closed between 1967 and 1975 due to regional conflict.
The Bosporus is a 17-mile long strait dividing Asia from Europe and connecting the Black and Mediterranean Seas. Roughly 3.1 million barrels of oil flow through the Bosporus each day. The Bosporus is less than a half-mile wide at its narrowest point and is one of the busiest and most difficult thruways to navigate. Weather and shipping accidents, not necessarily conflict or terrorism, are the primary concerns in this chokepoint.
The Bab el-Mandab (or Mandab Strait) connects the Red Sea with the Gulf of Aden. Roughly three million barrels of oil flow through this waterway each day. Closure of the waterway would prevent tanker traffic bound from the Persian Gulf from reaching the Suez Canal, primarily impairing exports to Europe. It was near this location that a small boat attacked the M/V Limburg, a French VLCC, in October of 2002.
The Panama Canal connects the Pacific Ocean with the Caribbean Sea. Approximately a half million barrels of oil transit the canal each day. Oil traffic is limited to smaller tankers (Panamax) due to narrow lock sizes. Most traffic through the canal is destined for the United States, although little of this traffic is crude oil.
[i] John H. Noer, Chokepoints: Maritime Economic Concerns in Southeast Asia, Washington: National Defense University, 1996.
This page last modified in August 2008