This week, a different heavy cargo ship struck a support column for the Francis Scott Key Bridge in Baltimore at around 1:30 a.m., prompting the 1.6-mile-long bridge to come crashing down into the water almost immediately. The collapse of the bridge Tuesday morning has disrupted trade from the Port of Baltimore, which handled $81 billion of foreign cargo in 2023. Rebuilding the bridge could cost hundreds of millions of dollars.

Six construction workers who were on the bridge are presumed dead, though officials have said a Mayday warning from the ship allowed the Maryland Transportation Authority police to close traffic across the bridge, probably preventing some casualties.

These two events, which took place almost exactly three years apart, occurred 5,000 miles from one another and in considerably different circumstances. But both involved enormous ships of the kind that have become the backbone of modern global trade. The Ever Given is what is known as an ultra-large ship, almost more than 1,300 feet long, with a gross tonnage of 220,000. The Dali ship, while still enormous on human scale, is a smaller ship with a length of around 980 feet and a gross tonnage of less than 100,000.

These large ships are a long way from the world’s first successful container ship, a converted steamship that traveled from New Jersey to Texas in 1956. Container ships slowly increased in size for decades after that, before suddenly leaping significantly in size over the past 20 years, forcing ports and canals to adapt, often at the cost of billions of dollars. But new shipping technology and the logic of economies of scale meant ships got bigger and bigger.

The Key Bridge opened in 1977 with a price tag equivalent to $316 million in modern figures. It was a mammoth piece of infrastructure engineering. Yet even it could not stand up to a modern container ship. Indeed, no bridge pier can withstand being hit by a ship the size of the Dali, Benjamin W. Schafer, a professor of civil and systems engineering at Johns Hopkins University, told my colleagues this week.

“These container ships are so huge,” Schafer said.

It isn’t just accidents that modern shopping has to worry about. Around 90 percent of international trade by volume is shipped via the oceans. These giant container ships traverse numerous geopolitical hot spots where actors have realized that blocking one or two ships can have a global impact that far outshines their initial outlay. While maritime trade has always been impacted by war, the size of current ships means a single successful rocket or drone attack could hobble a ship carrying hundreds of thousands of tons.

Last year, after Hamas’s Oct. 7 attacks on Israel led to a huge assault on the Palestinian enclave of Gaza, the Yemeni militant group known as the Houthis began attacking container ships and oil tankers in the Bab al-Mandab Strait. The attacks effectively cut off access to the Red Sea, and with it the Suez Canal, leading numerous freight shippers to reroute their voyages south around Africa’s southern tip, adding 10 days onto the average one-way trip.

Global shipping costs grew as a result, with supply chain experts estimating that global consumer prices could rise by up to 2 percent if the disruption were to last a whole year. Despite efforts by the United States and its allies to punish the Houthis for these attacks, they have so far not been able to.

The Bab el-Mandeb Strait is just one potential choke point for global shipping. On the other side of the Arabian Peninsula lies the Strait of Hormuz, where tensions between Iran’s Revolutionary Guard Corps and commercial ships regularly flare. There’s the Black Sea, where Russia has been able to block numerous shipments of Ukrainian grain since the war it invaded its neighbor in February 2022.

Along with the Suez Canal, the Panama Canal is increasingly seen as a worry for global trade. While the latter allows a speedy shortcut through the Americas, it is reliant on rainwater and has been hindered for months by drought conditions.

In Asia, there are fears about strategic shipping routes like the Malacca Strait, which connects the Indian Ocean to the South China Sea between Indonesia and Malaysia, as well as the Taiwan Strait, the body of water that separates the self-governing island from China.

Asia is a particularly worrisome region when it comes to shipping. This year, labor organizations in the United States wrote to the Biden administration to petition for trade relief for the U.S. shipbuilding industry, noting that Chinese-built ships, many of them enormous megaships built by state-owned companies, now dominated global maritime trade. As the Financial Times’s Rana Foroohar wrote this month, “America has essentially stopped building its own ships” over the past few decades.

Part of the reason for this move away from U.S. shipbuilding was that the raw materials and components needed to build these new ships were no longer produced in the United States, Foroohar noted. Ironically, these industries were the victims of the offshoring that only became possible after the surge in global trade produced by our new giant ships.

In many ways, the giant container ship may be a symbol of our age. The Dali may have been sailing into an American port, but the ship was constructed by the Korean firm Hyundai, operated by a crew of Indian nationals, owned by a Singaporean firm and carrying containers on behalf of a Danish shipping giant that were en route to Sri Lanka.

This sort of multinational operation for a single ship is not unusual.

When the Houthis attacked a ship that was carrying tens of thousands of tons of fertilizer from Saudi Arabia to Bulgaria last month, they justified the move by claiming the ship was British and thus belonged to an ally of Israel, whom they oppose for the war in Gaza. (The ship, the Rubymar, later sank, providing spectacular images). But the only link between Britain and the Rubymar was that a maritime database listed an apartment in Southhampton, England, as an address for the owner.

As the Financial Times observed, the ship “flew the flag of Belize, was partly managed by a Beirut-based ship management company, was on a voyage organized by another Lebanese operator and had a mostly Syrian crew.”

These opaque, transnational systems are the result of rampant globalization that enabled decades of booming economic growth. But that system doesn’t always look great. Aside from the risk of hitting a bridge, running sideways in a canal or getting fired upon by militants, these giant ships represent a oligopoly with a lack of competition, Rachel Premack wrote in a stinging critique for Freight Waves in 2022, often with dubious business practices including unregulated labor practices.

Investigators are looking into whether the power outage that appears to have led the Dali to hit the Key Bridge was caused by dirty fuel, contaminated by water, dirt and algae that could clog filters in the ship’s main generator. Ian Ralby, the CEO of IR Consilium, a maritime and resource security consultancy, told The Washington Post that the widespread disruption to global shipping routes may be exacerbating the problem.

“We may be in a situation where ships are going to be taking on fuel in places where they can’t guarantee the quality or caliber of fuel,” he said.