Strait of Hormuz: The Geography of a Global Chokepoint

Welcome to the first issue of Mapswire. My goal is to provide you with the geographical context behind the world's biggest headlines through free, yet high-quality maps and research. Let's dive into the most sensitive waterway on Earth.

The Strait of Hormuz has been the reason for heated international debates in the last weeks. To explain why this is a bottleneck with so much influence on the world economy, I've created a map showing the geographical situation.

The Hormuz Strait is the only sea passage from the Persian Gulf to the open ocean, connecting countries like Iraq, Kuwait, Bahrain, Qatar and even Saudi Arabia to the Gulf of Oman and the Arabian Sea. Roughly a quarter of the world's seaborne oil and also a quarter of global Liquefied Natural Gas (LNG) passes through it. Countries in South and East Asia are especially dependent on the resources provided through this strait, but even a short closing leads to a lack of supply, causing oil and gas prices to rise globally.

As the map clearly shows, the sea is rather shallow and dedicated shipping lanes have been introduced to help the vessels navigate through the sometimes flat, sometimes rocky waters. This Traffic Separation Scheme (TSS) separates inward from outward traffic to avoid collisions between ships.

The main problem, especially for the large oil carriers, isn't the passage through the core part of the Strait of Hormuz itself. The shipping lanes lead through the part of the sea that's controlled by Oman, and the border between Oman and Iran was agreed upon in 1974.

The real tension exists at the western end of the Strait. In 1971, just after the British retreated from what later would become the United Arab Emirates, Iran occupied the three islands of Abu Musa, Greater Tunb, and Lesser Tunb. The legal status of these islands is disputed, but the shipping lanes towards the Persian Gulf now lead right through waters effectively controlled by Iran – and Iran uses Abu Musa as a military base, equipped with drones and missiles.

So, not only does geography play a vital role in this conflict, but history does as well. And in this case, there's some real irony in what happened. In 1953, the USA helped to overthrow the democratically elected government of Mohammad Mossadegh and restored the absolute power of Shah Mohammad Reza Pahlavi. The idea was to have a strong partner in a region with vast oil and natural gas resources. The Shah used this to his advantage and seized those three islands, which after the Islamic Revolution of 1979 became a strategic nightmare for the West.

The consequences extend far beyond energy supply. About one-third of the world's Helium consumption comes from Qatar and has to be transported by large ships. The closing of the Strait has led to a sharp increase of Helium prices. As Helium is heavily used for semiconductor production, the already high prices for computer memory and other semiconductors will continue to rise. Helium is used in other applications was well, for example, it's used in MRI machines. Yes, geography may even affect our health.

Even the choice of what farmers decide to grow on their fields in the USA, and consequently the food prices, are affected by a closed Strait of Hormuz. The most widely used fertilizers also are by-products of the oil and gas production around the Persian Gulf. Restricted ship traffic leads to higher prices, causing farmers to grow plants like soybeans – which don't need as much nitrogen fertilizer — instead of crops like corn.

In the end, a narrow water passage with many islands and treacherous shoals controls not only the price we pay for gasoline for our cars, but also for the bread we eat.

I have made a high-resolution version of today’s map (4470×2846 / 408 KB) available on the Mapswire website exclusively for my subscribers. You can access the full-scale image via the link below. This map is released under a Creative Commons BY 4.0 license – you are free to share, use, or redistribute the map as long as you attribute it to Mapswire. Click here to download the high-resolution map from mapswire.com.

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P.S. Looking for more context? If you want to dive deeper into the region, you might find my maps of Iran and the Middle East helpful for understanding the broader geopolitical landscape.