Global markets were seized by fear last week that trade wars were slowing growth in Germany, China and the United States. But the story here is bigger than US President Donald Trump and his tariffs.

The post-war miracle is over. Since the financial crisis of 2008, the world economy has been struggling against four headwinds: deglobalisation of trade, depopulation as labour forces shrink, declining productivity and a debt burden as high now as it was right before the crisis.