A household that repeatedly loses animals to harsh winters may survive the immediate crisis while becoming poorer each year.

By the time archaeologists see a major decline in livestock, the economic damage may already have been underway for generations.

The walrus story also reaches far beyond Greenland.

Medieval Europe had a strong demand for ivory because ivory could be carved into religious objects, gaming pieces, decorative items, and other prestigious goods.

Greenland could supply a material that was difficult to obtain elsewhere.

But markets are not permanent.