North America is a highly urbanized region. In the period 1972-2000,
the percentage of North America's population living in cities increased
from 73.8 to 77.2 per cent (United Nations Population Division 2001).
Urbanization is related to many of the environmental issues highlighted
in this report, including the conversion of agricultural land, habitat
degradation and biodiversity loss, regional air pollution, global climate
change, coastal degradation, an increased urbanwildlife interface and
By the 1970s, the post-war exodus from central cities had led to a settlement
pattern characterized by low-density suburbs surrounding city cores, commonly
referred to as 'urban sprawl'. Addressing the multiple problems associated
with urban sprawl has become a priority in many North American municipalities.
Urban populations use high levels of energy and other resources and dispose
of large amounts of waste. Because of their significant contribution to
both regional and global pollution, and to declines in the Earth's natural
resources, North American cities have disproportionately large 'ecological