At any given moment, there are some 55,000 cargo ships at sea, plying the world’s oceans. They are transporting the goods and the groceries, fuels and food, cars and computers that form the backbone of global trade. But they also carry a heavy environmental cost when it comes to carbon emissions. Far from our big cities, less visible than our pollution-belching industries and motorways jammed with idling cars, giant cargo ships are also adding their considerable carbon footprint.

In the last 15 years, container ships have greatly increased in size – by “almost a factor of five” according to Matt Collette, who teaches ship design at the University of Michigan in the United States. The world’s largest ship, the Triple-E, operated by Danish shipping giant Maersk is 1,320ft (400m) long, almost the length of four football pitches, 240ft (73m) tall and 194ft (59m) wide. It can carry 18,000 standard 20-foot containers. If those containers were placed end-to-end on a train, that train would be nearly 70 miles (110km) long.

As we can’t live in this globalised world without these giants, how can we make them cleaner and more efficient? Could the answer be to make them sail themselves?

Attention spans

Giants like the Triple E may only (remarkably) be staffed by a crew of 20 people, but even so the type of automation advances touted as making cars and trucks safer could also be used to improve ships – even ships of such gigantic proportions. These marine giants could theoretically roam around the oceans without any crew at all, either fully autonomously or under control from a central ground station.

“There are two primary drivers for automation,” says Collette. “One is that human beings are not very good at long repetitive tasks.” Which is of course what standing watch on a long ocean voyage is. “That’s when you see lapses in concentration that lead to the ship getting into a collision or running aground,” he explains. “Automation could reduce those types of accidents significantly, because the computers have no problem paying attention for a two-month voyage.”