There is a lot more to cities than just buildings, but buildings play a crucial role in society's environmental impact. I suggested in yesterday's post on green cities that building design has an impact. Here are some more thoughts on why the issue is a lot bigger than replacing lightbulbs and using energy-efficient appliances.
First, the design of buildings affects the way we use them, which plays a big part in our contribution to greenhouse gases and other pollutants.
Their design should include consideration of the materials they are built from - the energy that goes into the manufacture of the materials, the impact of maintenance during the life of the building, and what will happen to the materials when the building is finally demolished. Some materials are easier than others to reuse in another building, or to recycle. Some designers - a precious few - are starting to consider this cradle-to-grave impact.
Design also affects how easily a building can be adapted for different uses; or, if it is a home, how it can be reconfigured to meet changing household needs as family or individual circumstances change. This flexibility (or lack of it) can have a significant impact on the need to put more energy into renovations or even demolition and reconstruction, and the cumulative impact across a city or nation can be significant.
Another aspect of design that is only addressed in the rarest of cases is the grading of energy and water, which is about using the right resource for the job. The obvious one is recycling grey water for toilets and irrigation instead of using drinking water for everything. Not easy to do, unless the system is designed in from the start. Resource management is going to become more and more important as the quality and quantity of resources diminishes, and is a big component of the planning now underway for Dongtan in China.
Once a building is complete and occupied, its thermal properties (insulation and storage of heat) affect energy consumption, and if it is designed to benefit from the sun, this can reduce the need for space heating and artificial light. This is another example of energy grading, and it's partly the responsibility of builders and architects, and partly of developers and planners who lay out the city grid of streets and determine whether buildings can in fact make use of the sun.
There are tools for assessing how well buildings perform, such as LEED and BREEAM and others for auditing environmental performance, and simulation tools are being developed to help designers.
As Juliana pointed out in her comment on my post on sustainable urban design last week, even the relatively simple aspect of waste management is often made difficult by poor design.
Second, the way buildings are located in relation to each other and other infrastructure and spaces affects the way we live our lives, and can present opportunities for more efficient use of resources.
This is about urban form and how it affects our need to travel to get to opportunities to work, play, shop, socialise and so on. Traditional zoning of land uses was developed to separate incompatible uses, but it's exacerbating travel problems. Given the right environment of regulations and municipal standards, buildings could be planned to reduce the need to travel to get to these opportunities.
BedZED is one example in the UK of a group of buildings designed to reduce environmental impacts not only by designing the building structures to reduce energy requirements, but also by encouraging the buildings to be used for work and living and by providing shared resources to reduce the duplication of some things that would normally be provided in every dwelling.
Buildings have, in the past, been grouped to share resources like furnaces for heating in cold climates. The low-income housing development of Regent Park, in Toronto, was an example of separate buildings sharing heating through underground pipes. This is rarely done now for residential buildings, but there is a growing awareness of the potential for combined heat and power (CHP) to improve efficiencies by looking at integrated systems, not electricity and heat in isolation. Local power generation and distribution, as I have said before, offers a lot of advantages over the traditional model.
Third, buildings last a long time, so their impacts are also long-lasting.
If they are poorly designed or located, the impacts of these decisions will be compounded over time. As new technologies emerge to reduce impacts, they cannot always be retrofitted to existing buildings, so it will take decades for cities to be transformed to reduce their impacts.
Tragically, even informal housing in squatter settlements in developing countries tends to be long-lasting. The poorly-made temporary structures are continually patched-up and rebuilt with whatever materials are to hand, but many governments faced with the challenge of housing the poor are unable or unwilling to replace these settlements with more formal ones. The result is that millions of people live in under-serviced, unsafe, polluted conditions that are, in effect, permanent.
So it's great to see developers taking the initiative to adopt renewable energy sources, efficient building systems and greywater recycling without any subsidy or other carrots or sticks applied by local government. It's still rare, but it does happen.
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