Virginia Tech researcher Arthur C. Nelson argues in a JAPA article that, shockingly, the end of suburbia (by the mid-21st century) will not necessarily be foretold by Peak Oil — but by the momentum of America’s current monumental (if somewhat under the radar) demographic shift towards smaller households living closer together.

To get from where Americans live today — 54% in larger-lot single family houses, 21% in townhouses and small-lot singles, and 25% in attached housing — to where they’d prefer to be living (assuming an increase in 34 million housing units by 2025), will result in net demand for 53 million attached houses, 52 million townhouses, and negative 22 million single family houses. Yes, negative. By some accounts, many cities are already oversupplied with single-family houses on larger lots.

This transformation of Americans’ cities by 2025 will cost our nation $30 trillion. The result:

[O]ver half of all development on the ground in 2025 will not have existed in 2000, even more important is that by 2025 much of society will have been spatially rearranged. An increasing number of empty-nesters, young professionals, and others will choose the city and first-tier suburban locations over outer suburban ones. According to Fishman (2005), they will drive up housing prices beyond the reach of many existing residents who may then be pushed to the suburban fringe and exurbs. Rising energy prices and declining demand for suburban homes on large lots may reduce the value of these homes, yielding important implications for the future.

Larry Frank’s SMARTRAQ research in Atlanta, examining one of the poster children of 20th century sprawl, finds that “about a third of metro Atlantans living in conventional suburban development would have preferred a more walkable environment.” Re-housing one-third of suburban residents would get us a long way towards the built environment that Nelson foresees a generation from now.