In 1992, families with children predominated, creating a market for single-family, single-lot homes in suburban greenfields—the American Dream; 2013 sees a different market emerging of younger and smaller households, most of whom seek rental apartments or smaller for-sale homes in urban places, while cities learn to create sustainable neighborhoods to accommodate a new settlement pattern shaped by many American Dreams.

The forthcoming 5th Assessment report of the Intergovernmental Panel on Climate Change, which contains for the first time a chapter on human settlements, infrastructure, and spatial planning.  Professor John R. Nolon participated in the expert’s meeting regarding this chapter and contributed his article, The Land Use Stabilization Wedge Strategy: Shifting Ground to Mitigate Climate Change, and an article by Meg Byerly, Staff Attorney at the Land Use Law Center, A Report to the IPCC on Research Connecting Human Settlements, Infrastructure, and Climate Change.  This chapter is still in draft and we anxiously await its circulation.

These issues are explored in my article for the Fordham Environmental Law Journal entitled Shifting Paradigms Transform Environmental and Land Use Law: The Emergence of the Law of Sustainable Development.

Changes in demographic trends are helping reduce the demand for economic development of sequestering lands and open spaces containing valuable ecosystem services; they are also increasing demand for housing and job development in urban areas and developed suburbs.  According to United States Bureau of Census estimates, the nation’s population will grow to over 400 million by mid-century, an increase of nearly 90 million over the 2011 population of 312 million.  The addition of 100 million people translates into 40 million new households, whose members will travel to live, work, and shop in new buildings provided for them, consuming energy on site and en route, and emitting CO2 if they travel by car.  The construction and operation of new buildings, as well as the vehicle miles travelled by car for daily work, errands, and pleasure, will therefore account for a significant percentage of annual energy consumption and CO2 emissions by mid-century.  If this building and this travel take place in the spread-out settlement pattern that predominated twenty years ago, these new people will consume huge amounts of energy and emit enormous amounts of CO2.

For a variety of reasons, however, the majority of the projected 100 million new Americans will be inclined to shift ground, preferring to live in dynamic, walkable neighborhoods in urban areas.  Key among these shifts is the housing preference among the growing number of older households who currently live in single-family homes on individual lots.  Today there are 40 million senior citizen households; by 2040 that number will have swelled to 80 million.  As these senior households age, many find single-family suburban living unsuitable and seek to move into housing in neighborhoods where services, goods, and entertainment are nearby—places where they can live independently and age in place.  Sixty percent of the seniors prefer to rent rather than buy new homes when they move, increasing the demand for rental housing, very little of which was produced over the past twenty years.

As a growing number of seniors offer their homes for sale, the supply of single-family homes available for purchase will increase, while the demand for it shrinks.  Other newly forming households in the decades ahead will be composed of younger individuals and couples, mostly without children who are seeking urban neighborhoods as well and are not inclined to purchase energy-guzzling single-family homes involving long commutes to employment, entertainment, and services.  Between 2010 and 2050, 70 percent of net gain in households will be among households without children.  This imbalance in supply and demand for single family homes means that there will be over 20 million unwanted large-lot, single-family houses on the market by 2025.  This will significantly reduce the market for newly-constructed suburban and exurban single-family housing.

These demographic trends are bolstered by economic realities.  Subprime mortgages, involving low down payments and flexible interest rates, are a thing of the past.  Available mortgages today require a 20 percent down payment, cash available for closing costs, and strong credit ratings.  These changes in the mortgage market mean that households seeking to purchase housing will buy smaller homes or seek to rent because they lack the cash and credit needed to qualify for a loan to purchase.  The cost of transportation from home to work is beginning to rival the cost of housing in many metropolitan markets for moderate- and middle-income families, further propelling households toward neighborhoods with transit or that are in closer proximity to centers of employment.

These demographic changes mean that market forces will support the movement of future populations into urban settlements and away from single-family neighborhood living.  This has profound consequences for land use planning and zoning at the local level in remote locations.  Shifting ground toward more climate-friendly and energy-conserving urban living is not a matter of social engineering through policy and legal change, but rather a market inevitability.  As a consequence, legal strategies will reorient themselves toward creating transit-oriented developments, energy-efficient, mixed-use and compact building types, and sustainable neighborhoods.  Legal techniques for remediating distressed properties, developing workforce and equitable housing, and insinuating urban amenities and excellent design in redevelopment areas will be ascendant, as will methods of redeveloping countless commercial and office buildings and strips in older suburbs.

The growth of the population by 100 million, combined with the obsolescence of current buildings, means that as much as 66 percent of the development on the ground in 2050 will be built between now and then.  This indicates that immediate changes in land use laws and settlement patterns can achieve significant results.  Many urban communities are responding positively by adopting higher density, mixed-use zoning, implementing transit-oriented development plans and ordinances, and using many other techniques to accommodate these changing market forces in a way that will reduce vehicle miles travelled and per capita GHG emissions.  As further evidence of the importance of these changes to managing climate change, the Intergovernmental Panel on Climate Change (IPCC) is adding a chapter to its Fifth Assessment Report on Human Settlement, Infrastructure, and Spatial Planning.