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Developing a hotter L.A.
Ali Modarres, Los Angeles Times
High-density development can create ‘urban heat islands’ that may add to global warming.
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Los Angeles’ accelerating quest to create centers of higher population density — especially downtown, in Hollywood and in Mid-Wilshire — may be on a collision course with California’s crusade to slow global warming by reducing its greenhouse gas emissions. And the potential trouble comes from an unlikely source — buildings.
High-density development is usually considered environmentally friendly if it occurs near subway, rail or bus lines, and people can abandon their cars to get around. But unless people actually do take advantage of public transit and reduce their energy consumption, the environmental costs may outweigh the benefits.
One effect of high-density development that can potentially increase energy consumption is a phenomenon known as the “urban heat island.” This is principally caused by the construction materials — brick, concrete, asphalt, stone and other substances — used most often in building central cities. Because these materials retain heat and cool slowly, they raise the ambient air temperature and make central cities a few degrees warmer than rural and suburban areas. For instance, the temperature difference between Phoenix and its outlying areas can be upward of 10 degrees. The difference is even more pronounced at night because rural and suburban areas have fewer buildings, less concrete and asphalt and more vegetation, and thus cool faster.
Packing taller residential buildings closer together to increase density, without making room for significant areas of green space, such as parks or shaded plazas, only worsens the effect.
This is not an earth-shattering revelation. Researchers have known about the effect of the urban heat island on ambient air temperature for more than 100 years.
Ali Modarres is a professor of urban geography and the associate director of the Pat Brown Institute at Cal State L.A. He is the co-author of “City and Environment.”
(9 September 2007)
Exercisers Stuck in Unwalkable Settings
Mike Stobbe, Associated Press
ATLANTA — Nearly one in four people in the Atlanta area are exercise enthusiasts stuck in neighborhoods without sidewalks or other walking amenities, according to a study that illustrates a problem for many Americans. Researchers said the findings point to the need for more exercise-friendly places to live.
“The bottom line is the built environment really does matter to health,” said Lawrence Frank, a University of British Columbia researcher who led the study.
Walkable, mixed-use neighborhoods have sidewalks leading to nearby shops, restaurants or other destinations. They are built in a way that makes it easier to walk and get to buses and trains. Many are older neighborhoods, located in more urban areas.
Frank is among a group of scientists who have shown that people who live in walkable neighborhoods tend to weigh less than people who live in more isolated and car-dependent areas.
(7 September 2007)
Related from Seattle P-I: Seattle Walks: Feet-wise investing.
Big Houses Are Not Green: America’s McMansion Problem
Stan Cox, AlterNet
The recent mansion boom produced millions of energy-wasting homes with thousands of square feet that Americans don’t need — not the behavior of a society that’s thinking about a sustainable future.
In Los Gatos, Calif., controversy has raged this summer over the city planning commission’s approval of a proposed hillside home that will occupy a whopping 3,600 square feet – and that’s just the basement. Atop that walkout basement will be 5,500 more square feet worth of house.
The prospective owner says he’ll build to “green” standards, but at the Aug. 8 meeting where the permit was approved, the city’s lone dissenting planning commissioner stated the obvious when he told the owner, “You have a 9,000-square-foot house with a three-car garage and a pool. I don’t see that as green.”
The just-popped housing bubble has left behind a couple of million families in danger of losing their homes to foreclosure. It has also spawned a new generation of big, deluxe, under-occupied houses bulked up on low-interest steroids.
The National Association of Home Builders (NAHB) estimates that 42 percent of newly built houses now have more than 2,400 square feet of floorspace, compared with only 10 percent in 1970.
(8 September 2007)
