Wednesday, August 21, 2013

Despite Upswing in City Population Growth Rates, Suburbs Still Outpace Cities in Numerical Growth

by George Masnick
The Census Bureau recently released 2012 population estimates for cities and towns to complement the 2012 population estimates for metropolitan areas released in March.  With these two sets o f data it is possible to examine the split between primary city and suburban population growth trends.  My favorite blogger about census data, Bill Frey of the Brookings Institution, quickly released a commentary on these new data with the lead sentences: “Big cities could be making a growth comeback after a rocky decade. Their growth rates are rising and, for the second year in a row, they are growing faster than their surrounding suburbs.” 

He goes on to note that: “Among the 51 metropolitan areas with more than one million residents, 24 saw their cities grow faster than their suburbs from 2011 to 2012. That was true of just 8 metro areas from 2000 to 2010. Metropolitan areas exhibiting the largest city growth advantages included Atlanta, Charlotte, Denver, and Washington, D.C.”

Frey based his analysis entirely on growth rates, but it is the growth numbers that are more relevant for understanding city versus suburban housing demand.  When population growth numbers are examined, only 12 metros had greater numerical growth in the cities versus in their suburbs. Only seven metros on Frey’s list of 24 cities with higher growth rates than their suburbs also had higher numerical growth (Austin, Columbus, Louisville, Nashville, New Orleans, New York and San Diego).  Cumulatively, overall suburban population growth in the nation’s 51 largest metro areas outstripped overall primary city growth for 2011-2012 by a ratio of almost 2:1 (Table 1).  Atlanta, Charlotte, Denver, and Washington, DC, the four metro areas Frey singled out for their large city growth advantage, had suburban growth numbers that exceeded city growth numbers in 2011-2012.  (Click table to enlarge.)

** Abbreviated name.  Primary cities are defined as the metropolitan area’s largest city and up to two additional cities with populations exceeding 100,000.

Nor are the places where cities have a numerical growth advantage necessarily trending to increase that advantage. Of the 12 metros where cities had more absolute growth in 2010-11, six didn't sustain that advantage in 2011-12, and four saw a decline in the advantage.  Only two metros had city growth advantages that increased in 2011-2012 (data not shown).

The key to explaining the differences between growth rates and growth numbers, of course, is the fact that for most large metro areas the suburbs have more people than the cities. Of the nation’s 51 largest metro areas, only five had greater primary city populations in 2012.  Three are sprawling metros located in the South and West (Austin, San Antonio and Jacksonville), and the remaining two in this category butt up against other metros and geological barriers to suburban growth (San Jose and Virginia Beach).  The vast majority of suburbs contain more population than primary cities, with Atlanta having more than 11 times as many people living in the suburbs; Hartford, Orlando, Providence, and St. Louis around eight times as many, and Washington, DC over 6 times.  Percentage rates of growth calculated on such disparate population bases are really not comparable.

Primary city population growth has been reinforced in recent years by the aging of the echo boom into the young adult population, because young adults often move to cities to go to college or to work.  Large gains since 2005 in the 18-34 age group have helped turn city growth rates positive in many cases.  There were 3.8 million more 18-34 year olds in 2011 than there were in 2005.   Young adults who move to primary cities of large metros have made the 18-34 age group the largest of the three age groups plotted in Figure 1.  In the suburbs of these metros, the 55+ age group is the largest. 

Source: 2010 Decennial Census.  For a list of metro areas see Table 1.

There are three main demographic drivers of population change in the suburbs of large metropolitan areas.  First, and most important, is the aging of the suburban population. An aging population creates two pressures for population growth to slow.  The children of these households are themselves becoming adults, fleeing the nest and often heading for the city or to places outside of the 51 largest metro areas.  As these suburban households age, deaths also increase and births decrease. 

The second driver of suburban population growth is the housing turnover of aging baby boomers.  Household dissolution from death or divorce could create opportunities to boost population growth from younger and growing households who replace them. Life cycle migration out of the suburbs of large metro areas by smaller baby boomer households as they enter the empty-nest stage or retire from the labor force does the same.  However, the Great Recession and its slow recovery has dampened housing turnover in recent years through a variety of mechanisms.  Among the most salient of these are high unemployment and slow wage growth; owners who would like to sell but are underwater with their mortgages; tight mortgage lending by banks; more people working past age 65; loss of home equity wealth that was counted on to partly fund retirement plans; and lower immigration levels reducing housing demand.

The third driver of population growth in the suburbs has historically been new housing construction that attracts in-migrants.  Again, new construction during the Great Recession and its slow recovery has been at historic lows, and suburban growth has slowed as a consequence. 

Looking forward, the aging of the baby boom will continue to dampen population growth in the suburbs.  Most baby boomer households will simply age in place and decline in size. Over the next two decades, some housing that is freed up by household dissolutions by cohorts born before 1945 and by the oldest boomers, or by housing released by these cohorts who do retire to other places, will help mitigate population loss in the suburbs because those buying their houses are likely to be younger than the sellers and have larger household sizes.  But the greatest opportunities for housing turnover in the suburbs will not take place until baby boomer households dissolve in significant numbers beginning in 2030.

During the next decade, some of the factors that have depressed housing turnover in the suburbs in recent years should run their course.  New housing construction will be needed to accommodate adult population growth from aging echo boomers, and possibly the next wave of immigrants. This should largely take place outside of primary cities - where land is more readily available. 

While I do concur with Frey’s point that large city population growth is a welcome positive for their health and vitality, I also agree with his suggestion that a rebounding housing market could lure echo boomers, immigrants, and retirees out of large cities in the future.  While suburban growth rates will never approach the levels experienced in their earlier years, the suburbs should continue to grow in population now and well into the future.

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