UNLESS you are a hermit, you own and consume things that have passed through the port of Rotterdam. Last year the port handled 466m tonnes of cargo, more than double the amount of Europe’s second port, Antwerp. The endless shifts in the size and composition of these flows provide an instant indicator of the state of the world economy. And the trends that are transforming the port’s operations—automation and the shift away from fossil fuels—give a sense of the future too.

Thanks to its easy access for big ships from the Atlantic and for barges from the interior, Rotterdam has been Europe’s dominant port for much of modern history. Its success is man-made: in the mid-19th century, when the Ruhr region of Germany was industrialising, Rotterdammers dug a channel to connect the Maas river, which runs through the city, to the Rhine, creating the most shipworthy route from Europe’s industrial heartland to the North Sea.

The port has been evolving in sympathy with the global economy ever since: in the mid-20th century, new handling and storage facilities for oil and chemicals were built to cater to the post-war boom. As globalisation gathered pace in the 1990s and 2000s, the port expanded further into the sea, to provide berths for the mega-ships bringing sneakers and flat screens from Asia to Europe.

Activity at the port today bears witness to four trends currently shaping the world economy: the low price of oil, slow growth in China and emerging markets, the sluggish euro-area recovery and the global slowdown in manufacturing and trade. From his office overlooking the Maas, Eelco Hoekstra, the boss of Vopak, the world’s largest independent storage company of “all things liquid”, sees the physical manifestation of movements in energy markets sailing by each day.

In 2014, he recalls, when fracking was flooding America with cheap natural gas, huge cargoes of American coal suddenly started floating past. Gas was displacing coal in America but remained expensive in Europe, since America had little export capacity. So European utilities began snapping up the unwanted American coal instead: more of it was exported to the Netherlands than to any other country in 2014 and the first half of 2015.

Soon after, the price of oil collapsed. Big consumers expected a relatively prompt revival, however, judging by the price of futures contracts. Rotterdam’s vast storage tanks quickly filled, as traders bought cheap crude on the spot market and sold futures at a higher price, locking in a profit. The low oil price, meanwhile, has helped pad margins at refineries and chemical plants, spurring a flurry of activity in Rotterdam’s sprawling industrial complexes.

The oil price fell thanks in part to slowing growth in China, which is also evident in the sudden appearance of Chinese ships offloading surplus steel. This in turn means fewer barges are taking iron ore down the Rhine to German steel mills. Declining sales of German cars in China compound the problem, as carmakers consume less steel. The drop in shipments of bulk goods arriving in Rotterdam, says Allard Castelein, CEO of the port, is a direct result of this baleful cycle.

The relative strength of the American and British economies is some compensation. In 2015 so-called “RoRo” (roll-on roll-off) traffic of lorries crossing the North Sea to Britain increased by 13% compared with the year before. America-bound cargo has also held up well. There are also a few countries from which imports to Rotterdam are growing fast. As wages in China have risen, says Roderick de la Houssaye of van Uden, a logistics firm, his clients—particularly makers of shoes and clothes—are relocating. Some have gone to places with lower wages, such as Indonesia and Vietnam; others to closer manufacturing regions such as Turkey, which are less likely to suffer from transport disruption.

Some people see “near-shoring” to places like Turkey as a sign that globalisation is ebbing. The Baltic Dry Index, which tracks the cost of moving raw materials by sea, hit a record low in February. That is partly the result of a ship-building binge, but also of faltering demand. For the past few years world trade has been growing no faster than the world economy—the reverse of the usual pattern; in dollar terms, it declined by almost 14% in 2015. All this can clearly be felt in Rotterdam, where one in four containers originates in China. “When Singapore’s harbour is empty, it’s hard to see how we can be full,” says Mr Castelein. Although the volume of goods handled in the port grew by 4.9% last year, this was almost entirely thanks to the increased trade in oil and oil products. Container volumes dropped by 1.1% and agricultural bulk by 3.8%. Whether this slowdown is just a temporary dip or a permanent one is the subject of a heated debate. Mr Hoekstra is convinced that intercontinental trade will continue to grow. In the past 15 years he has seen shipments of oil and refined products quadruple. The main driver, he says, is a growing imbalance between those who have natural resources and those who need them. As oil and gas production becomes ever more concentrated in a few places, the need to ship and store the stuff will only grow, he thinks. Russia and the Middle East have too much oil; Asia too little. Europe has a shortage of diesel but a surplus of gasoline, which South Africa, in turn, wants more of—and so on.

Port in a storm

But Bart Kuipers of Erasmus University argues that a number of trends all push in the same direction: less container traffic. Economies are shifting from industry to services; advances in logistics and technology, such as near-shoring and 3-D printing, are making it more practical to manufacture things in the rich world; recycling drives are sapping the incentive to import.

Rotterdam provides much more conclusive evidence of another trend that will shape the world economy: automation. Earlier this year its crane-drivers, often referred to as “the kings of the terminal”, went on a 24-hour strike that paralysed large parts of the port for the first time in 13 years. They were protesting against competition from robots. In 2013 the opening of “Maasvlakte 2”, which extended the port by a fifth by reclaiming land from the sea, was welcomed as a feat of engineering not just because it made the Netherlands 20km² (8 square miles) bigger, but also because its new “ghost” terminals run with almost no human intervention. In an episode of “The Wire”, a hit American TV drama, a stevedore at the port of Baltimore declares a jazzy promotional video about Rotterdam to be a “horror movie”.

AGVs on the march In this part of the port, there is no hustle and bustle. Crane-drivers have been replaced by “remote crane operators”, who sit in a distant office in front of computer screens, using joysticks to control as many as three cranes at once. The cranes lift containers onto self-driving, battery-powered automated guided vehicles (AGVs), which deliver them to stacks to be distributed by truck, train or barge. When their batteries run out, the AGVs drive to a depot where robots remove the spent ones and insert replacements. It is eerily quiet and dark, as the AGVs do not need light to navigate. Humans’ main role is to stay out of the way; an AGV is about as heavy as a small aircraft and the whole system shuts down if any unexpected people or vehicles enter the terminal. APM Terminals, which operates part of Maasvlakte 2, hopes each crane will be able to move over 40 containers per hour in this way, compared with 30 or so in less advanced facilities. That cuts shipping times, saving lots of money. It is also far safer and, as one shipping executive notes, “Robots don’t take breaks or strike.” Sensing mortal danger to their livelihoods, workers are threatening more strikes unless the management promises to preserve their jobs and salaries. Another area of evolution concerns how the new parts of the port are powered. The AGVs and cranes in the new terminals are all electric, and an increasing number of windmills and solar panels provide much of the power the port consumes. All this reduces emissions of greenhouse gases, in keeping with increasingly restrictive European rules. The port is also investing in all sorts of climate-friendly experiments, from using residual heat from industry to warm homes and offices in the city to storing carbon under the seabed. Nonetheless, notes Jan Rotmans of Erasmus University, “Everything in the port breathes fossil.” Much of its business comes from the shipping and storing of oil, coal and other polluting fuels. Shell and ExxonMobil recently announced that they would spend some €2 billion ($2.2 billion) expanding their refineries in Rotterdam.

Mr Rotmans wonders whether this business will continue to grow. That depends on whether the rest of the world will follow the port’s lead in terms of curbing its emissions. Rotterdam and other ports are not perfect bellwethers for the world economy: they give little indication, for instance, of what is happening in services, since lawyers and consultants don’t tend to travel in ships. But, horror movie or not, it is hard to deny that Rotterdam’s docks reflect glimmers of the future.