The unchecked trend of US exurbanization was one of the major factors setting off the beginning of the global financial crisis of 2008-2009, according to a new research paper published by the Post Carbon Institute investigating the relationship of sprawled, completely car-dependent communities to real estate risk as well as to climate change and ecosystems.

Besides the inherent threats to climate change and dwindling resources, exurban development during the past decades put the United States in a vulnerable economic position when steadily rising gas prices in 2004-2005 began their march toward $4-5 a gallon in mid 2008. 

The research paper argues that many suburbs and most exurbs, which constitute the vast majority of urbanized areas in the United States, have been building up an infrastructure of complete auto dependence, which threatens the climate through multiple forms of inefficient energy, food and resource use.

Despite the emerging "green" urbanism trend, which can be found in a number of North American cities, unplanned exurban growth must be addressed and managed more efficiently, or the economy will face further severe national real estate shocks as oil prices rise again.

California's Senate Bill 375 is the first statewide anti-sprawl measure, and similar regulation and related regional planning processes will need to occur on a national basis to systemically reduce the combined risks of exurban development and financial speculation. 

The following is an excerpt from the complete paper, a publication pre-release of the "Roadmap for the Transition" series.

In April 2009 -- just when people thought things couldn't get worse in San Bernardino County, California -- bulldozers demolished four perfectly good new houses and a dozen others still under construction in Victorville, 100 miles northeast of downtown Los Angeles.

The structures' granite countertops and Jacuzzis were removed first. Then the walls came down and the remains were unceremoniously scrapped. A woman named Candy Sweet came by the site looking for wood and bartered a six-pack of cold Coronas for some of the splintered two-by-fours. For a boomtown in one of the fastest-growing counties in the United States, things were suddenly looking pretty bleak...

The recent decline of Victorville and other "boomburbs" may well prove to be the last gasp of the United States' decades-long suburban/exurban development frenzy. We will be absorbing or trying to erase the unwanted surplus of this end-of-the-twentieth-century building spree for years, if not decades. In the meantime, exurban communities in general -- and Victorville in particular -- will face a daunting set of short term and long term challenges as the 21^st century shapes up to be very different than the world they were built for...

Within the United States, existing metropolitan areas can be retrofitted to take advantage of breakthroughs in sustainability and efficiency technologies, as well as new financial incentives.

The American Recovery and Re-investment Act of 2009 has provided some funding for the energy-efficient redesign of our buildings and our means of transportation. But much more ambitious projects need to be undertaken to retrofit our communities not only for energy efficiency, but to build their overall resilience.

Fortunately, a foundation for this work already exists. Barely ten years ago, "green buildings," downtown streetcars, urban farms, car-sharing companies, high-quality bicycle infrastructure and other physical features now associated with urban sustainability were found only in a handful of North American cities. Today, they are popping up everywhere.

Big cities like New York, Los Angeles and Chicago are actively trying to "out-green" each other, while smaller cities like Boulder, Colorado, and Alexandria, Virginia are rolling out their own localized sustainability solutions.

Some communities have taken early steps toward protecting their surrounding agricultural lands, or "foodsheds," from well-established regional plans and policies in Portland, Oregon to San Francisco's 2009 comprehensive local food policy. Cities are starting to realize that they can't just "grow smarter" -- they have to fundamentally remake themselves to be resilient for the unprecedented economic, social, and environmental challenges of the 21st century.

Some metro areas rethinking themselves for resilience have simultaneously become home to "clean tech" centers with significantly high job growth rates. Clean tech clusters are emerging in the San Francisco Bay Area, Boston, and Austin, as well as in some less-expected locations; in Toledo, Ohio, for instance, more than 4% of all jobs are now in research, development and manufacturing for solar energy. Other key areas of future job growth are in green building and landscaping, water conservation technologies, low-carbon materials design and advanced transportation...

If the "Great Recession" of 2008-2009 taught us anything, it was that allowing the unrestrained sprawl of energy-inefficient communities and infrastructure is not a sustainable economic development strategy; rather, it is a recipe for continued disaster on every level.

Twentieth century-style sprawl has destroyed valuable farmland, sensitive wildlife habitat, and irreplaceable natural water supply systems at great environmental, economic, and social cost. We can no longer manage and develop our communities with no regard for the natural resources and ecological systems that provide our most basic needs.

What lessons emerge from metropolitan areas that have begun to plan for the future by building their resilience with economic, energy, and environmental uncertainty in mind?

• Build and re-build denser and smarter. Suburban and urban population densities need to increase so that energy-efficient transportation choices like public transit, bicycling and walking can flourish. Multi-modal mobility cannot succeed at the densities found in most American suburban and urban communities today. Increasing density doesn't have to mean building massive high-rises: adding just a few more stories on existing or new mixed-use buildings can double population density -- and well-designed, increased density can also improve community quality of life and economic vitality. Resource-efficient building technologies, as certified by the US Green Building Council's Leadership in Environment and Energy (LEED) or the US EPA's Energy Star rating, can be retrofitted for existing building stock and mandated for all new construction.
• Focus on food. Gardens (whether in backyards, community parks, or in and on top of buildings) may supplement people's diets with fresh local produce -- but urban areas need to think big and plan systemically for significantly increased food production. In many Asian cities and towns -- even big cities like Seoul, South Korea, the size of New York -- there are thriving small farms interspersed within metro areas. Growing and processing more food for local consumption bolsters regional food security and provides jobs while reducing the energy, packaging and storage needed to transport food to metro regions.
• Focus on water. Our freshwater supply is one of our the most vulnerable resources in the United States. Water vulnerability is no longer just a problem for Southwestern desert cities -- communities in places like Texas, Georgia and even New Jersey have recently had to contend with water shortages. As precipitation patterns become less reliable and underground aquifers and mountain snowpack dry up, more and more communities will need to significantly reduce water demand through conservation, restrictions and "tiered pricing."
• Think in terms of systems. If we think of our urban areas as living, breathing entities--each with a set of basic and more specialized requirements--we can better understand how to transform our communities from random configurations into dynamic, high-performance systems of resilience. The "metabolism" of urban systems depends largely on how energy, water, food, materials, labor and knowledge are used (and reused, where possible), or metabolized. From these ingredients and processes come products, services, and -- if the system is efficient -- minimal waste and pollution...