Seven Rules for Sustainable Communities

Design Strategies for the PCarbon World

Patrick M. Condon

• Editore: Island Press
• Anno: 2012
• ISBN:
  9781597268202
• Argomento: Architecture
• Categoria: Architecture générale

Questions of how the design of cities can respond to the challenge of climate change dominate the thoughts of urban planners and designers across the U.S. and Canada. With admirable clarity, Patrick Condon responds to these questions. He addresses transportation, housing equity, job distribution, economic development, and ecological systems issues and synthesizes his knowledge and research into a simple-to-understand set of urban design recommendations.

No other book so clearly connects the form of our cities to their ecological, economic, and social consequences. No other book takes on this breadth of complex and contentious issues and distills them down to such convincing and practical solutions.

CHAPTER 1

Introduction

Figure 1.1. Icebergs floating in Jokulsarlon Lagoon, Iceland. One hundred years ago, this lagoon did not’ exist; it was under one hundred feet of glacial ice. (Credit: Deborah Benbrook, iStock)

In 2002, scientists sounded the alarm about the loss of ice on the Arctic Ocean. Global warming was affecting the arctic climate more rapidly than anyone had previously thought possible. They predicted that if nothing was done to curb the level of greenhouse gas (GHG) pouring into the atmosphere there might be no summer ice covering the North Pole by 2050. Early in 2009, they updated their projection. Given the rate of ice loss, the new date by which the Arctic Circle will be ice free could be as soon as 2012. The loss of ice triggers other effects, none of them good. The white ice that once reflected warming sun rays no longer does so. The deep blue ocean water that takes its place absorbs those rays, warming the water and further accelerating the warming of the planet. Bad things happen in threes. The added heat also releases methane gas that was previously trapped under polar ice. Methane gas, like carbon dioxide (CO₂), traps heat in the atmosphere, but molecule per molecule it is many times more damaging. The cascading effects of climate change, previously predicted for the distant future, are already here.

Experts at the United Nations–sponsored Intergovernmental Panel on Climate Change (IPCC) all agree that the two-degree-Celsius rise in global temperature, the so-called “safe” level of warming that we will still get even if we cut GHG emissions by 80 percent, is a rise that is unavoidable. The IPCC predicts that, even at this “safe” temperature increase, up to 50 percent of the planet’s species will become extinct. But we are on a path where GHG produced from the burning of fossil fuels is not dropping but increasing rapidly. With a five-degree rise, much more would be lost. Former U.S. vice president Al Gore, when seated before a U.S. Senate hearing on climate change held in January 2009, was asked if a five-degree rise in global temperature would “end life as we know it”. “No, Senator,” he replied, “people will survive in some form, but likely all of our institutions would collapse and billions would die.”

What have all of these gloomy scenarios to do with a book on city design? Everything. If we change the way cities are built and retrofitted, we can prevent the blackest of the nightmare scenarios from becoming real and can create the conditions for a livable life for our children and grandchildren. It is not apocalyptic to say we can save their lives.

Normally, GHG production is described by sector. We often read that buildings account for about half of all GHG production; transportation, for about 25 percent; and industry, for most of the rest.¹ But this division obscures a fundamental point: cities are responsible for 80 percent of all GHG—caused by the way we build and arrange our buildings, by all the stuff we put in them, and by how we move from one building to the next. Since the problem is caused by cities, the solution should be there too.²

Citizens and their elected officials have been slow to acknowledge the connection between GHG and urban form. This book may help change that. It is written for designers, policy makers, developers, regulators, and ordinary citizens in the hope that it will arm them with an understanding of the ways our cities are failing and offer them very specific actions to cure them.

HOW DID CITIES GET THIS SICK?

In any journey, it helps to start with a look back from where we once came. Various historical starting points could be studied, but the end of World War II marks the time after which cities changed the most. Many compelling reasons drove the crucial choices we made at that time; foremost among these was the need for a place to live.

After World War II, a variety of policy inducements provoked a massive redistribution of population across metropolitan landscapes. In the United States, the mortgage interest income tax deduction, low interest GI loans, restricting new mortgages through bank “red lining” of older residential areas, and the 1956 National Interstate and Defense Highways Act, which funded the construction of the interstate highway system, were most significant.³ Provoked by these inducements, middle-class and working-class families who had traditionally occupied higher density walkable and transit-served neighborhoods fled to much lower density and car-dependent suburbs.⁴ Average densities began to fall in every North American metropolitan area, while transit ridership as a percentage of all trips began to fall with it. Older, prewar parts of the metropolitan landscape still maintained healthy transit ridership, but transit use in newer areas was near zero.⁵

Figure 1.2. Sprawl outside of Calgary, Alberta. (Credit: Micycle, Flickr.com)

As North Americans moved from transit to cars, their per capita GHG amounts began to rise too. Of course, no one worried. GHG production was not important at that time, as the implications of this increase were not widely known and were even less widely accepted. Buying fuel for the family car was also not a concern, as prices were low.⁶ The brand-new high-speed freeways provided previously unimaginable freedom of motion, allowing workers to hold jobs twenty-five or more miles from home.⁷ This was a massive change that fundamentally altered the reach of cities. In 1950, the Boston metropolitan urbanized area was only 345 square miles. In 2000, it sprawled over 1,736 square miles, a quintupling in only five decades (U.S. Census Bureau, 2000a).

During this period of dramatic metropolitan expansion, land was generally less expensive on the peripheries. This made it profitable to build residential developments ever farther away from the metropolitan center, with single-family homes generally dropping in price as one moved farther out. This concentric reduction in house prices gave rise to the saying “drive till you qualify,” a widely used phrase meaning that home buyers were induced to push a home search farther and farther from the center of the region until their income matched the qualification requirements for the mortgage.

With so much unprecedented freedom of movement in this new urban landscape, house price became much more important than location. A distant job was easy to reach, and shopping centers catering to millions of auto nomads were soon to come. Eventually, vast stretches of the metropolitan landscape become completely car dependent, forcing individuals and families to spend more and more time behind the wheel and to rack up ever increasing vehicle-miles traveled (VMT).

The new single-family homes were not only auto dependent but, because of their shape and exposure to the elements, also inherently hard to heat. We now know that the GHG production of this style of home is up to four times greater per capita than that of home types common to older center cities.⁸

Not only price but school quality strongly influenced location decision. Here, newer communities had a distinct advantage over older ones. Newly developing areas had new schools, whereas older areas had older schools that were populated by children from families without the economic resources to follow the migration and that were located in cities hampered by declining property values to fund them adequately. Of course, the new schools were sprawling one-story buildings that were impossible to reach on foot, requiring expensive fleets of carbon-producing buses to ferry children back and forth.⁹

Unquestionably, this new low-density and car-dependent development pattern successfully supplied millions of new housing units at prices that North Americans could afford. This success has led many to claim that sprawling urban areas are more affordable than those with metropolitan growth controls. For example, for decades well-financed lobbying groups have attacked Oregon’s growth controls, in force since 1974, on this ground, even though Portland’s housing costs are lower than other similar-sized western U.S. communities, such as San Diego, Seattle, San Francisco, and Sacramento—all metropolitan areas with no such laws. ¹⁰ Thus, the claim that low density is more affordable than higher density cannot be credible.¹¹ This is especially true when transportation costs are considered. The more sprawling the metropolitan area is, the higher the percentage of family budget devoted to auto use. When these additional costs are factored in, the “affordable” house in a third-ring suburb is not nearly so affordable, a fact made sadly obvious when in 2008 the combination of sky-high gas prices and the mortgage meltdown led to the virtual abandonment of many subdivisions in third ring suburbs.

Low-density sprawl also costs much more per dwelling unit to service than does higher density development. A subdivision of single-family and duplex units on 2,800- to 3,300-square-foot lots can be serviced for 75 percent less per dwelling unit than can single-family homes on larger lots of 8,000 to 9,000 square feet. The cost of providing streets and utilities to a new home can be substantial. Each home requires a certain amount of paved street, storm drains, and utilities before it can be occupied. At lower densities, the cost of providing required streets and services can be over $100,000 per dwelling unit.¹² Home buyers are seldom aware of this cost, which is always buried in the cos...