Open Source Content Management

Writing in US monthly The Atlantic, architect Witold Rybczynski outlines his "green case for cities", arguing that there is too much focus on flashy green gadgets and not enough on practical building methods:

Putting solar panels on the roofs doesn’t change the essential fact that by any sensible measure, spread-out, low-rise buildings, with more foundations, walls, and roofs, have a larger carbon footprint than a high-rise office tower—even when the high-rise has no green features at all.

He also has a pop at the media for encouraging the "green gadget" trend:

Architectural journals and the Sunday supplements tout newfangled houses tricked out with rainwater-collection systems, solar arrays, and bamboo flooring. Yet any detached single-family house has more external walls and roof—and hence more heating loads in winter and cooling loads in summer—than a comparable attached townhouse, and each consumes more energy than an apartment in a multifamily building. Again, it doesn’t really matter how many green features are present. A reasonably well-built and well-insulated multifamily building is inherently more sustainable than a detached house. Similarly, an old building on an urban site, adapted and reused, is greener than any new building on a newly developed site.

Rybczynski leaves his most important point to the end, suggesting the future could be developments that are "dense without being vertical". He cites Montreal as an example of city where the dominant form of housing is a three or four-storey apartment block that doesn't require elevators.

Rybczynski makes a good point - while high rise is often touted as the solution to unsustainable urban sprawl, tall buildings typically require elevators, artificial ventilation (due to increases wind speeds and noise associated with openable windows at height) and heavy, high embodied energy structural components - perhaps three or four storey "walk ups" represent an ideal compromise.

But without solid figures, it's impossible to be sure. Does anyone know of any studies out there examining the energy footprint of different building forms?

I saw this in the Guardian yesterday - leading UK environmentalist Tony Juniper encouraging the British government to introduce a boiler scrappage scheme. Such a scheme would offer householders grants to replace their old boilers with new, high efficiency ones. It would work similarly to the UK car scrappage that offers money to those trading old cars for new ones.

Juniper writes:

The simple idea is that by replacing the country's old, inefficient gas boilers it would be possible to achieve a major environmental benefit and conserve a valuable resource while at the same time creating employment and economic activity...
 
...Reheat Britain suggests that a limited and temporary fund is created, mostly from public sources but perhaps also including contributions from boiler manufacturers. It would work along similar lines to the car scrappage scheme, and it is estimated that an incentive of about £200 per boiler would be needed.

  Juniper says that replacing a G-rated boiler with an A-rated condensing boiler with better controls could cut household energy bills by a quarter. He says that the carbon cost of making and fitting new boilers would be quickly compensated for by the high efficiency of new, A-rated units.

He also speculates that the idea could be slow getting approval in political circles because of the absence of lobbying power in the heating sector compared to the motor industry.

Cities have the potential to store vast amounts of carbon, according to a new study. National Geographic reports on the work of Galina Churkina of the Leibniz Centre for Agricultural Landscape Research in Germany:

Churkina and colleagues pulled together previous evidence looking at various stores of organic carbon—carbon that comes from living things, as well as from such as plants and animals, wood, dirt, and even garbage.
Cities—including both dense metropolises and sprawling suburbs—store about a tenth of all the carbon in U.S. ecosystems, the study estimated.
In total, U.S. cities contain about 20 billion tons of organic carbon, mostly in dirt, according to the new study to be published in an upcoming issue of the journal Global Change Biology.

Many cities have already launched ambitious plans for turning gray to green, such as Los Angeles' Million Trees LA project, which aims to plant a million trees in the Californian city over several years.

Building timber instead of concrete houses could also help to sequester carbon, said Leif Gustavsson, an expert on green technology at Mid Sweden University. But he said the main carbon benefit is from the embodied energy of the construction itself, rather than carbon stored in the material.                                     

Meanwhile, earth scientist David Pataki of the University of California stressed that getting urban soils to store more carbon would be a careful balancing act. "Managing urban soils to store more carbon can use energy, and those fossil fuel emissions have to be taken into account," he told National Geographic.