IN MID-JANUARY a storm gathered over Lake Michigan. Gale-force winds dragged water up and dumped it on Milwaukee. The city was “pummelled”, says Adam Tindall-Schlicht, the director of its port, which was badly damaged. Dock walls were ripped off and washed inland. The trade routes the port serves, including those for steel from Europe, were disrupted. Climate change has exacerbated the risk of such storms. Mr Tindall-Schlicht notes that water levels on the Great Lakes have never been so high.
Seaports are by their nature exposed to the elements. But they are also choke-points of global trade, handling 80% of the world’s goods. So disruption at a port can have far-reaching consequences. When Hurricane Katrina shut down three ports that process 45% of America’s agricultural goods, national food prices rose by 3%. Hurricane Harvey had a similar effect on the price of fuel. One study modelled floods hitting the port of Rotterdam in the Netherlands. It estimated the impact on trade would add an extra 64% to 86% to the overall cost, on top of the direct damages.