The story of what's happened at Michigan over the last decade plays out in a new book by John Bacon.
Coffee growers in Central America are facing a crisis because of a fungus that’s affecting the crop. The “roya” leaf rust fungus makes the plants lose their leaves and destroys some of the coffee beans.
In Guatemala, two-thirds of the coffee is affected and hundreds of thousands of jobs are at risk.
The BBC’s Humphrey Hawksley reports.