Suez, Panama and the Arctic routes – the passages world trade runs through

Sea transport is the cheapest way to move something heavy a long way. That is why it pays to produce in Asia and sell in Europe, and why it has paid for decades.

But cheap over distance does not mean robust. Almost all of world trade is squeezed through a small number of narrow places, and that is where the vulnerability sits.

This episode is about the most important of them, what actually constrains each one, and what happens when one of them closes.

Why a handful of places decide so much

A ship can go almost anywhere. It is the land in between that forces it through particular points.

Without Suez goods between Asia and Europe have to go around the whole of Africa.
Without Panama goods between Asia and the US east coast have to go around South America, or be unloaded and carried overland.
The consequence: two canals built more than a century ago still decide what things cost in a shop in Norway.

Suez

The Suez Canal opened in 1869 and links the Mediterranean to the Red Sea. Its most important technical feature is something it does not have: locks.

The canal runs at sea level the whole way, between two seas that sit at roughly the same height. That means no lifting, no water consumption and no capacity limit tied to rainfall. The constraint in Suez is width, depth and traffic management – how many ships can pass each other, and how deep they sit.

It is also why a grounding can paralyse the canal completely. Without locks there are no parallel chambers to route traffic through.

Panama

The Panama Canal opened in 1914 and links the Atlantic to the Pacific. It is shorter than Suez, but technically far more complicated, because it does not run at sea level. Ships are lifted up to a lake, cross it, and are lowered again.

Why Panama is vulnerable in a completely different way

The ship is lifted in locksUp to Gatún Lake, which sits well above sea level.
Every lock operation uses fresh waterThe water runs out to sea when the ship is lowered again.
The water comes from rainfallThe lake is filled by rain in the surrounding watershed.
Drought becomes a capacity limitLess rain means fewer transits per day, and a lower permitted draft.

This is the most counterintuitive thing in the episode. Panama's constraint is not space, and not demand. It is water. The same canal can take far fewer ships in a dry year than in a wet one, with nothing physically changed – and the canal competes for the same water as the country's drinking supply.

Panamax and Neopanamax

Because the locks have fixed dimensions, the Panama Canal has given its name to a whole class of ship. A vessel is not built larger than the canal it has to pass.

Two generations of locks

Panamax

The original locks

Dimensions from the works that opened in 1914
Defined ship size for generations
Still in use

Neopanamax

The 2016 expansion

Up to 370.33 metres length, from May 2021
Up to 51.25 metres beam, from June 2018
Draft up to 15.24 metres, depending on water level
Normal capacity 9–11 vessels a day

Note that the dimensions have been revised upwards several times since the 2016 opening. That is not because the locks were rebuilt, but because operating experience made fuller use of them defensible. And note the draft: it is given as "depending on water level", which is exactly the point from the previous figure.

The Arctic routes

It is worth separating two things that often get conflated here: the Northern Sea Route north of Russia, and the Northwest Passage through the Canadian archipelago.

The argument for both is the same, and it is real: the distance between north-east Asia and northern Europe is considerably shorter over the top than through Suez.

Why shorter is not the same as better

Obstacle	What it means in practice
Ice	The route is not open year-round, and ice conditions vary from year to year.
Ship class	Ordinary container ships are not ice-strengthened. It takes purpose-built, more expensive vessels.
Escort	Icebreaker escort costs money, and has to be planned.
Insurance	Higher risk means higher premiums, and some underwriters will not cover it.
Emergency response	Long distances to port, little infrastructure, and an environment where a spill is extremely hard to clean up.
Predictability	Container lines sell fixed sailings. A route that varies with the ice suits liner traffic badly.

The last point is the most commonly underestimated. Liner shipping is not about being fastest once, but about being able to promise the same arrival day every week, all year. A route that is three weeks faster in summer and closed in winter does not solve that problem – it creates it.

The detour

When a main route cannot be used, alternatives exist. They are simply expensive in a way that is not obvious.

What happens when ships have to go around Africa

The voyage gets longerSeveral extra weeks on Asia–Europe, and more fuel per trip.
Ships are occupied for longerA ship on a detour is out of the market for that extra time. The fleet shrinks without a single vessel disappearing.
Capacity tightensFewer available ships against the same demand raises freight rates – including on routes that are not affected.
Schedules slipPort calls shift, containers end up in the wrong place, and empties pile up where they are not needed.

Step two is the key, and the one that explains why a disruption in one place raises prices everywhere. The effect is not that the route becomes more expensive. The effect is that total transport capacity in the world becomes smaller, because every ship spends longer on every trip.

Since late 2023, much of the traffic between Asia and Europe has gone around the Cape of Good Hope instead of through the Red Sea and Suez, because of the security situation. The scale has fluctuated considerably, and several carriers have switched back and forth as the risk picture has changed. Traffic volume figures should therefore always be taken from up-to-date sources, not from an article.

How to read the news about this

Always ask what the binding resource is.

In Suez: width, depth and traffic management.
In Panama: fresh water.
In the Arctic: ice, season and predictability.
And in the market as a whole: how many ship-weeks are available – not how many ships exist.

What is worth taking with you

That sea transport is cheap over distance, but vulnerable at a few narrow points.

That Suez has no locks, which both makes it simple and makes it easy to block completely.

That Panama’s constraint is water, not space.

That Arctic routes are shorter, but lose on predictability – which is what liner shipping actually sells.

And that a detour does not only cost the ships taking it, because it pulls capacity out of the whole market.

Canal authority dimensions and rules change. For current dimensions, draft and daily transit numbers, the Panama and Suez canal authorities’ own notices apply.

Main topics

Why a handful of places decide so much
Suez – the canal without locks
Panama – the canal that runs on fresh water
Panamax and Neopanamax, and what the dimensions mean
Arctic routes, and what actually limits them
The detour around the Cape of Good Hope
What a blocked route costs
How to read the news about this

Questions this episode answers

Why are Suez and Panama so important?
What is the difference between the two canals?
What do Panamax and Neopanamax mean?
Why does drought limit the number of ships through Panama?
How much shorter is the Arctic route?
Why is the Northern Sea Route not used more?
What happens when ships have to go around Africa?

Key points

Sea transport is cheap over distance, but vulnerable at a few narrow points.
Suez has no locks. Panama has locks, and they consume fresh water.
Panama's constraint is water, not space – drought reduces the number of daily transits.
The Neopanamax locks take vessels up to 370.33 metres long and 51.25 metres wide.
Arctic routes are shorter in distance, but limited by ice, season, escort and insurance.
The detour around the Cape adds weeks, and ties up ships that then disappear from the market.
A route closed for some is more expensive for everyone.

Sources and references

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