A decade after the global financial crisis, household debts are considered by many to be a problem of the past after having come down in the U.S., U.K. and many parts of the euro area.

But in some corners of the globe—including Switzerland, Australia, Norway and Canada—large and rising household debt is percolating as an economic problem. Each of those four nations has more household debt—including mortgages, credit cards and car loans—today than the U.S. did at the height of last decade’s housing bubble.

...