Many homeowners in Denmark, like their American counterparts, enjoy 30-year fixed-rate mortgages. But thanks to a quirk of their housing-finance system, Danish sellers are able to earn a profit when they trade in their low mortgage rates for more-expensive ones, making it easier to move even when rates rise. As a result, the Danes dodge the lock-in effect entirely.

Implementing a similar system in the US would require an overhaul of our mortgage market and would almost surely be met with lots of foot-dragging from regulators and investors. But the alternative — twiddling our thumbs until the next Housing Ice Age — is far worse. Maybe it’s time we take a page out of the Scandinavian playbook instead.