Rapid and chaotic urbanization is taking a massive toll on human health and the environment

How the world tackles the social and environmental challenges of urbanization,

will determine the future of humanity and the fate of the planet

The global shift from rural to urban is the defining trend of our time

"The international community has been too slow in recognizing the growth of urban poverty,"

many cities are "environmentally unsustainable" and "rapidly becoming socially unsustainable."

environmental problems facing cities are profound, including energy and food production, air pollution, transportation and waste disposal.

those challenges are providing fertile ground for new sustainable solutions

"Cities are great centers of innovation and that is even more true today than it has been in the past,"

Cities are also increasingly realizing that they are on the front lines of climate change

and that could provide momentum for a global cooperation on the daunting issue.