Detroit Mayor Dave Bing moved swiftly to announce the city would challenge the accuracy of the official count and focus like a laser on luring new residents and new business.
"We must confront reality ... and commit to doing things differently," Bing said at a news conference. "If we don't change, the population drain will continue."
But Bing -- and his successors to come -- faces long odds. No large American city has restored its numbers after such overwhelming decline.
Many cities have refurbished themselves with new cultural attractions, redeveloped neighborhoods or spruced up downtowns. Cleveland built the Rock and Roll Hall of Fame in 1995, which has drawn more than 7.5 million visitors. Baltimore redeveloped its inner harbor into a tourist and shopping destination, while Johns Hopkins University redeveloped east Baltimore near its medical campus in the city's largest redevelopment project. But none of the efforts has halted the population decline.
"The real question for Detroit is what are you going to do to bring in a new economic base to replace the auto industry," Andrew Beveridge, a sociologist at Queens College in New York, told AOL News. "That's very hard to do."
Kenneth Johnson, a demographer at the University of New Hampshire, said that turning Detroit around runs counter to the major demographic trends that have urban centers holding even at best, while most urban growth has hop-scotched the suburbs into the exurbs.
"Not only do you need dramatic redevelopment, you need demographic trends running contrary to nationwide trends that are going on," Johnson told AOL News. "I don't know of a city that has pulled something like this off."
Detroit is only the extreme example of the decline of large cities all across the Rust Belt -- and sometimes beyond it -- that has gone on for decades. In the 2010 census, Cleveland lost 17 percent, Cincinnati 10.4 percent, Chicago 6.9 percent, Dayton, Ohio, 14.8 percent, Pittsburgh 8.6 percent. Even Baltimore, on the thriving Washington-Boston corridor, declined by 4.6 percent.
The best example of a city's successful reinvention occurred in Pittsburgh after the collapse of the steel industry in the late 1970s. Over 30 years, Pittsburgh reinvented itself as a health care and high technology hub, and by the 1990s had remade its job market with high-wage jobs that attracted young college graduates.
"You see now a more diverse economy, higher wages, more young educated people moving back," said John Austin, a lecturer at the University of Michigan and director of the Brookings Institution's Great Lakes Economic Initiative.
But the city is also much smaller than it was. At its largest, in 1950, Pittsburgh's population was 677,000. The 2010 census puts it at 305,704.
Macomb County, Mich., grew by 6.7 percent. More residents now live in Macomb County -- 840,978 -- than live in Detroit.
In the past 10 years, Michigan lost some 600,000 of the million auto industry jobs that once supported Michigan's economy.
"The auto industry was downsizing and restructuring all decade," Austin told AOL News. "As the great recession hit, it just sent it into free fall. We lost more jobs than we have left."
Detroit also lost nearly 186,000 black residents to the suburbs, the largest-ever exodus of African-Americans from the city, but remains almost 83 percent black.
And, Austin said, Detroit looks better now than it did in the 1980s, when the crack epidemic and crime made urban decay much more vivid.
"Detroit's always had for the last 25 years a lot of empty lots and empty properties after streets of working-class homes began to be abandoned," he said. "It's always been very spooky that way. It's less physically depressing than it was 25 years ago. It doesn't have the general feeling of urban chaos that there was two decades ago. But part of that is there are fewer people, too."