Before this year, Tobias Kammann, a German container ship captain, had only once sailed around the southern tip of Africa, and the lack of other vessels in the little-traveled waters made him feel very much alone. But these days, there are so many ships there, he said, that “it’s a bit like the autobahn.”

To get from Asia to Europe and back, global shipping companies have for decades sailed through the Red Sea and the Suez Canal. But a year ago, the Houthi insurgents in Yemen began targeting vessels in the Red Sea with drones and missiles, forcing shipping companies to divert their cargo around the Cape of Good Hope at Africa’s southern tip, a route that is some 3,500 nautical miles and 10 days longer.

Western-led naval fleets were sent to the Red Sea to quell the attacks, which the Iran-backed Houthis said were a response to Israel’s war on Iran-backed Hamas in the Gaza Strip. Despite those deployments, the attacks continued, and commercial vessels have, for the most part, stayed away. And Middle East analysts said they expected the Houthis to keep up their attacks even as Iran’s influence in the region has diminished after the weakening of Iran-backed Hezbollah in Lebanon and the collapse of Bashar Assad’s government in Syria that was propped up by Iran, Hezbollah and Russia.

It’s as if the shipping industry had been transported back to the days before the Suez Canal opened in 1869.

“This is one of the most significant challenges that shipping has faced in a long time,” said Salvatore Mercogliano, a maritime historian and an associate professor at Campbell University in North Carolina.

On average, 136 container ships a week have traveled around the Cape of Good Hope this year, compared with 40 before the Houthi attacks started, according to data from Lloyd’s List Intelligence, a shipping analytics company.

Now, as this great diversion enters its second year, the costs are piling up for importers and countries like Egypt that rely heavily on maritime revenue. And the stress on shipping is likely to increase if companies rush to bring in imports before any tariffs imposed by the next Trump administration.

Before the Houthi attacks, the canal handled 10% of world trade and more than a fifth of global container shipments, according to the United Nations.

The Red Sea upheaval came just as importers were enjoying some of the lowest shipping rates in years, thanks to a glut of freighters.

But the diversion around Africa has increased the need for vessels — more were deployed to maintain regular service over the longer route — and rates have surged. The cost of shipping a container from Asia to Northern Europe is up 270% in 12 months, according to Freightos, a digital marketplace for shipping.

The demand for ships has pushed up rates everywhere. The cost of shipping a container from China to a West Coast port in the U.S. is up 217% over 12 months.

The rise in shipping rates has well exceeded the rise in costs at the big shipping companies, driving their profits sharply higher. Lloyd’s List data shows that passage through the Suez Canal has fallen 70%, which has deprived Egypt’s government of revenue.