"By 2030, more than 60% of the world's population will live in urban areas," said UN Secretary General Kofi Annan in an opening speech to the 2005 World Environment Day in San Francisco from 1 to 5 June. In the next 25 years, he said, "almost all population growth will occur in cities, most of it in less developed countries".
The problem, Annan warned, is that city planning is "haphazard". An environment atlas - One Planet Many People - showed the 50 mayors satellite pictures of sprawling urbanism over the past few decades and the effects they are already having on the world's environment.
UN Environment Programme chief Klaus Toepfer explained: "Cities pull huge amounts of resources [and] export large amounts of wastes including household and industrial wastes, wastewater and the gases linked with global warming. Thus their impacts stretch beyond their physical borders affecting countries, regions and the planet as whole."