ABSTRACT
Urban designers take responsibility for the setting of the dimensions that define urban form. More than in past decades, we now realize that decisions about dimensions made in the past have great bearing on the causes of climate change. This is true for the surveyors who laid out the streets and blocks of San Francisco as well as those who laid out suburban subdivisions. For example, already in 1847 Jasper O’Farrell was pressed to extend the grid of streets onto land that eventually would be reclaimed, thus providing level ground in an otherwise hilly terrain, but also preconditioning the future financial district of the city with the threat of inundation. But O’Farrell also laid out urban blocks now widely seen as a sustainable urban form in the light of climate change. While later chapters deal with suburban patterns, chapter one dwells on the merits of urban blocks, more precisely the perimeter block. This type of block lines all four streets of a block with rows of buildings in an equal manner. The center of the block remains open to the sky, provides room for trees, or for smaller buildings that function as annexes to the properties they sit behind. Confronting theories about urban blocks with perceptual evidence, the chapter reports on interviews done with residents who occupy such blocks. The results confirm and sometimes refute such theories. Threshold values of urbanity are met more easily if all public movement is channeled along the streets surrounding perimeter blocks. The perception of density is lowered if residents are offered orientation of their flats to front and rear. The inclusion of nature in the form of direct light and the sight of trees in the center of the blocks mitigates the sense of being crowded by neighbors. The research also shows the conditions under which residents are likely to reduce their carbon footprint, and when such conditions are not met. The chapter ends with a discussion on residential footprints in comparing six historic perimeter blocks and three contemporary blocks. Not unlike the computation of carbon footprints per resident, a residential footprint reveals land area as a ratio per individual resident. For urban designers, conserving space and reducing distances between city functions is a prerequisite for addressing the causes of climate change.
