What is the form of the ideal city? If the goal is to reduce our impact on the environment the answer would seem to be a very high density urban core surrounded by much lower densities punctuated by points or corridors of higher density. This form results in the best outcomes for greenhouse gas emissions and habitat loss, which are the two most pressing issues for environmentalists. Interestingly, this same city form is also ideal for achieving a healthy economy and a socially dynamic culture.
The two greatest environmental challenges we face are habitat loss and climate change. The moral imperative of tempering our impact on the other forms of life we share the planet with becomes even greater when it is our own social order and even the survival of our species that could be at stake. The increasing awareness and public concern for the environment means we must realign our priorities. Values that were once thought sacred will become just another competing priority to be weighed against others. Urban forms once thought inferior will become favored. Aesthetic preferences based on historic sentimentality will lose their appeal as the urgency of our situation becomes more apparent.
In terms of habitat loss the denser the development the better. Suburban neighborhoods can take over eight times as much land to accommodate the same number of people in a mid-rise neighborhood. When compared to high-rise neighborhoods the land consumed can be over 30 times as high. This does not include the land required to service and support these neighborhoods. Suburban encroachment into wilderness areas is an important factor in the degradation of ecosystems.
A typical suburban home can take four times as much energy to operate than a home in a higher density building. Those living in a high density urban core consume far less energy than those in the periphery. In Vancouver those living downtown generate about 1.5 tons of gases per person per year. Those living just outside the core generate twice that amount. The majority of Vancouver’s more suburban inner neighborhoods generate between six and 8 tons. Most of Vancouver’s electricity for home use is generated by damming rivers and therefore very little greenhouse gas is emitted. If this were not the case Vancouver would achieve 15 or 20 tons per person in the outer suburbs such as is seen in other North American cities.
The energy that goes into the construction of a building when considered over its entire lifecycle is not very significant. Whether it be high-rise, mid rise or suburban form this amount is under 10%. It is the energy taken to operate building forms and the transportation modes they must use that differentiates them.
Because detached houses have more surfaces exposed to the elements and are generally larger per person their operating costs are higher. A high-rise tower will take more energy to operate than a midrise in part because they tend to have more glass and are often narrower. Suburban neighborhoods have such low densities that adequate public transit cannot be sustained and private automobiles are the principal means of transportation. In mid-density neighborhoods public transit use is dominant while in high density neighborhoods travel by foot becomes the preferred form of transportation.
Environmental considerations bring a moral element to the argument for higher density. It may be that environmental concerns help rally the energies and sustain their commitment to a new vision of the North American city. Developing solid environmental data and good models for different options of development is of the highest importance.
A single high density core in an urban region is very economically efficient and environmentally benign. But there are also compelling arguments for punctuated densification throughout the low density suburbs as the low carbon footprint of these dense centers brings down the environmental impacts caused by the lower density neighborhoods. This punctuated density could be accommodated along the natural streetcar corridors.
If indeed this analysis of the kind of urban area we should be striving for is correct, it is quite obvious that this is not what is happening in our region. The current reality as well as the official plan is to have multiple centers that will disperse residential and economic concentrations into disjointed and energy intensive forms determined by political considerations and not environmental, economic and social ones.
The Center for Fourth Wave Urban Reform seeks to challenge current politically generated orthodoxy and to explore the use of market forces to generate more environmentally sustainable, economically prosperous and socially dynamic cities. It recognizes that the main impediment to achieving these goals is the web of postmodern planning constraints placed on cities during the third wave of urban reform.