by Vanessa Keith
Much of the literature related to the role of the built environment in climate change has focused on new technologies and new ideas which might be implemented in new buildings. Tabula rasa eco-cities trumpeting their green credentials and high levels of environmental sustainability are being planned in the U.S., China, and Abu Dhabi, among other places, and green is the word of the day. Despite these ambitious plans for new cities, one might ask, with all the urban fabric which currently exists, why build at all, and most especially on such a massive scale?
Starting from scratch is not the only way. Given the urgency of the massive changes to our way of life that must take place over the next seven to ten years, I believe that strategies which involve a retrofit or a clip-on to our existing structures and infrastructures deserve a serious look.
Retrofitting our urban building stock to address climate change need not be limited exclusively to increasing their energy efficiency. If “one of the primary causes of global environmental change is tropical deforestation” (Geist & Lambin, 143), then we should approach the adaptation of our buildings as an exercise in reforestation. Deforestation is too often divorced from urban discourse around climate change. In an attempt to redress that, my investigation into sustainable retrofits has included research into some causes of and solutions to deforestation, including a list of interventions already being implemented in the developing world (click here to read more). We must learn from both the causes of climate change and attempts to combat it as we attempt to reforest the city.
The City as Usable Surface Area
A densely populated city replicates its ground surface area many times over in the surfaces of the buildings that populate it. New York City, for example, covers some 309 square miles (801 sq km) of land area, much of which is built up. As of the 2000 census, there were 7,679,307 housing units in the five boroughs. A recent New York Times article quantifies the amount of available roofspace in the city alone as 944 million square feet, 11.5% of the total building area the city holds. Given that the population on the planet is rapidly increasing and due to double over the next 100 years, we may soon need all the available arable land for growing crops, with marginal lands where food crops provide inadequate yields relegated to biofuel crops (Killeen, 39). As the available space for the necessary green technologies is limited, it makes sense, therefore, to consider the city as the surface for our intervention.