The phrase "closing decades" refers to the final years or period of a specific time frame, often a century or a millennium. It signifies the end of that era or period. Full definition
The world is still warming as a result of coal burned in power stations that closed decades ago, and no one suggests that we should not worry about this. (johnquiggin.com)
In the 80s, John was a bonafide teen star — hanging around the Brat Pack crowd before closing the decade with «Say Anything,» the movie that crowned him as the American Prince of the Romantic Comedy. (bullz-eye.com)
Most of the resorts closed decades ago, and Cuomo says there may be no region in New York that has more potential to grow as a tourist destination. (timesunion.com)