The Unique Climatic Zone Known as Cities

Cities may feel like the antithesis of the natural world, but they obey the same rules as do the most pristine patches of wilderness. Just like mountains and valleys, buildings and pavement create their own distinctive environments—and none so distinctive as urban street canyons, the spaces between high-rises and above the streets that run between them. Studies show that the shape of street canyons (the length of blocks and the height of buildings relative to street width) strongly influence the local climate. Urban climatologists are working to predict how canyon design can affect temperatures, winds, and the concentration of pollutants. Learning how to optimize these spaces is an increasingly urgent problem: As of 2008, the urban environment has become simply “the environment” for the majority of the world’s population.