biosphere

Phoenix is more of a biosphere than other U.S. cities. Infrastructure is what makes it habitable on most days. It’s an air-conditioned city. Like other U.S. cities, its infrastructure is alien to the surrounding ecology. Masonry, concrete and asphalt retain the heat far longer than desert sand, which is why it doesn’t cool down as much it used to at night. Before, nighttime temperature rarely approached 90 degrees. Today 100 degree temperatures are more common.