The Ecology of Cities: Urban Planners Are Starting to See Cities as Complex Systems That Ought to Be Conceptualized in a Way That Mimics Natural Processes
Tomalty, Ray, Alternatives Journal
"URBAN SUSTAINABILITY" is one of those phrases that many people use but no one can concretely define. It may, however, be this plasticity that has allowed the concept to morph over the 20 years or so that we've been struggling to implement it.
At first, the term was used to describe any concerted effort by a community to reduce the environmental impacts of its operations, such as recycling and composting, improving energy efficiency of municipal buildings, managing traffic to reduce congestion, preserving wetlands, or minimizing leaks in the municipal water system. The logic behind these initiatives was that municipalities could continue more or less as they always had, as long as they seized opportunities to conserve resources and avoid the more egregious environmental impacts associated with urban development. Each municipal department identified such opportunities and--apart from the scattering of jurisdictions that created interdepartmental committees--continued to work in a "silo," more or less isolated from other departments.
Urban planners and managers are coming to realize that this compartmentalized and incremental approach to urban sustainability is limited in its capacity to address the major issues facing urban areas. Most importantly, it doesn't address the synergetic and cumulative effects of urban activities, doesn't connect local with regional impacts, and doesn't consider long-term and downstream effects. In short, the approach fails to unleash the full potential of the sustainable development model.
Today, many advocates of urban sustainability are pushing the agenda further, attempting to reach the underlying processes that structure our relationship with nature and shape the ecological outcomes that result from our actions. Instead of looking at individual components of an urban centre in order to minimize impacts, they are starting to look at the city itself as a system that needs to be analyzed and managed in a way that mimics natural processes.
The emphasis is now on systems thinking, relating site-level decisions to regional concerns, looping and integrating components of the urban system, and taking a long-term perspective. From this viewpoint, problems are seen as interconnected, and solutions are multidimensional. This approach highlights opportunities to squeeze savings (in energy, land, water and money for infrastructure) from the synergies that become apparent when we look at things in an integrated way. For example, heat exchangers can recover the "waste" energy that is in city sewage and use it to heat buildings--as will be the case in the athletes' village for the 2010 Winter Olympics in Vancouver.
Several emerging trends are nudging scientific and policy-making communities in this direction. Most importantly, humanity is coming to realize that it is speeding toward important limits--in the supply of fresh water, the loading of pollutants into the environment, greenhouse gas emissions and the destruction of ecological lands--that cannot be surpassed without major ecological and economic disruption.
We know now that we cannot continue with business as usual and hope that minor adjustments will keep us within the "Goldilocks zone"--the astronomical term for the zone where the planet is just the right distance from the sun so that its surface is neither too hot nor too cold to support life. Rather, we must shift our efforts away from manipulating nature to suit our needs and toward managing ourselves in order to keep our activities within recognized ecological limits. As Oliver Brandes points out in his 2005 paper, "At a Watershed: Ecological Governance and Sustainable Water Management in Canada," which was published in the Journal of Environmental Law and Practice, "Ecosystem-based management adapts economic, political and social processes to fit within the ecosystem, instead of the reverse."
At the same time, we are becoming increasingly aware that healthy ecosystems can provide us with the services we need to enjoy a high quality of urban life at a fraction of the cost that we would spend trying to replace them with engineered processes. …