Like a mature ecosystem, a city is shaped by its users. Any healthy system produces waste, whether it is a digestive system, an ecosystem or a citysystem. It is helpful to think of the abandoned, in-between, leftover land in cities as leaves on a forest floor, or fish bones on a seabed; if the system is functioning properly, all will be absorbed back in. The waste itself is an indicator of the system’s health and vitality. Without abandoned spaces, how can a city turn inwards for growth? If a city is truly healthy, elastic, and vital, it will continue to produce wastescapes, only to reabsorb them to produce something new. By their nature, elastic things are at times taut, and at other times slack; it is in slack times that citizens (root word: “city”) can choose a path of abandonment or one of revitalization; they can leave, or they can take a stand and snap back to a taut state.
We can’t know whether specific extreme weather events are the direct effects of global climate change. However, we ignore the chance at our own peril. Pervasive car culture and creeping sprawl are the result of federal policies that unfortunately have much more localized consequences. Horizontal spread really should be dealt with on a single horizontal level of policy, namely the regional level. Densification in and of itself is not the solution to save declining cities for which there my be many causes for blight and abandonment, but coupled with the most important element of all—a willingness for elasticity, flexibility, fluidity, and agility—it is an important place to start. Local and regional authorities bear the burden of having to take the most effective action, as they are where the policies will be most effective. We have seen the need to align our notion of ownership with one of stewardship, recognizing existing ecosystem borders as more significant than political borders in deriving ecosystem services sustainably. Most important, we have seen the integral role of collective citizen participation and initiation in policy response; even below the local level, change starts with one individual. From the concrete canyons of New York City to the informal riverside settlements in Jakarta, it is this single most important motivator in the improvement of infrastructure, both hard and soft. The city and its citizens work together as a system, each an essential component without which the other would not exist.