An analysis of 2000-2008 census data by the Brookings Institution highlights the demographic "tipping points" seen in the past decade and the looming problems in the 100 largest metropolitan areas, which represent two-thirds of the U.S. population.
The findings could offer an important road map as political parties, including the tea party movement, seek to win support in suburban battlegrounds in the fall elections and beyond. In 2008, Barack Obama carried a substantial share of the suburbs, partly with the help of minorities and immigrants.
The analysis being released Sunday provides the freshest detail on the nation's growing race and age divide, which is now feeding tensions in Arizona over its new immigration law.
Ten states, led by Arizona, surpass the nation in a "cultural generation gap" in which the senior populations are disproportionately white and children are mostly minority.
This gap is pronounced in suburbs of fast-growing areas in the Southwest, including those in Florida, California, Nevada, and Texas.
"A new metro map is emerging in the U.S. that challenges conventional thinking about where we live and work," said Alan Berube, research director with the Metropolitan Policy Program at Brookings, a nonpartisan think-tank based in Washington. "The old concepts of suburbia, Sun Belt and Rust Belt are outdated and at odds with effective governance."
Suburbs still tilt white. But, for the first time, a majority of all racial and ethnic groups in large metro areas live outside the city. Suburban Asians and Hispanics already had topped 50 percent in 2000, and blacks joined them by 2008, rising from 43 percent in those eight years.
The suburbs now have the largest poor population in the country. They are home to the vast majority of baby boomers age 55 to 64, a fast-growing group that will strain social services after the first wave of boomers turns 65 next year.
Analysts attribute the racial shift to suburbs in many cases to substantial shares of minorities leaving cities, such as blacks from New Orleans in the aftermath of Hurricane Katrina in 2005. Whites, too, are driving the trend by returning or staying put in larger cities.
Washington, D.C., and Atlanta posted the largest increases in white share since 2000, each up 5 percentage points to 44 percent and 36 percent, respectively. Other white gains were seen in New York, San Francisco, Boston and cities in another seven of the nation's 100 largest metro areas.
"A new image of urban America is in the making," said William H. Frey, a demographer at Brookings who co-wrote the report. "What used to be white flight to the suburbs is turning into 'bright flight' to cities that have become magnets for aspiring young adults who see access to knowledge-based jobs, public transportation and a new city ambiance as an attraction."
"This will not be the future for all cities, but this pattern in front runners like Atlanta, Portland, Oregon, Raleigh, North Carolina, and Austin, Texas, shows that the old urban stereotypes no longer apply," he said.
The findings are part of Brookings' broad demographic portrait of America since 2000, when the country experienced the attacks of Sept. 11, 2001, a historic boom in housing prices and the worst economic downturn since the Great Depression.
Calling 2010 the "decade of reckoning," the report urges policymakers to shed outdated notions of America's cities and suburbs and work quickly to address the coming problems caused by the dramatic shifts in population.
Among its recommendations: affordable housing and social services for older people in the suburbs; better transit systems to link cities and suburbs; and a new federal Office of New Americans to serve the education and citizenship needs of the rapidly growing immigrant community.
-About 83 percent of the U.S. population growth since 2000 was minority, part of a trend that will see minorities become the majority by midcentury. Across all large metro areas, the majority of the child population is now nonwhite.
-The suburban poor grew by 25 percent between 1999 and 2008 - five times the growth rate of the poor in cities. City residents are more likely to live in "deep" poverty, while a higher share of suburban residents have incomes just below the poverty line.
-For the first time in several decades, the population is growing at a faster rate than households, due to delays in marriage, divorce and births as well as longer life spans. People living alone and nonmarried couple families are among the fastest-growing in suburbs.