5.6 Urbanization and Sprawl

Notes

Over half of humans live in cities, and the share keeps rising.

• Urbanization is the growth of the share of people living in cities. Urban sprawl is low-density development spreading outward from a city into farmland and natural land.
• Effects of sprawl: loss of farmland and habitat, more car travel and air pollution, more impervious surfaces (pavement and roofs) that stop water from soaking in and increase flooding and runoff.
• The urban heat island effect: cities are warmer than surrounding areas because dark surfaces absorb heat and there is little vegetation.
• Smart growth solutions: compact, walkable neighborhoods, public transit, mixed-use zoning, urban growth boundaries, green roofs, parks, and redeveloping brownfields (abandoned polluted sites).
• Example: a city adds a green roof to cool buildings and absorb rainfall.