By 2008, over half the people on earth will live in cities says the World Watch Institute's 2007 State of the World report

Over the past century, there has been an historic shift in global population away from scattered rural communities to densely settled urban centers. By 2008, over half the people on earth will live in cities. The challenges created by this demographic change are the focus of a new report.

Each year over 60 million people migrate to the world's cities, mostly to impoverished urban settlements in some of the poorest countries on earth. Countries where unplanned and chaotic development - especially in Sub-Saharan Africa and South Asia - has resulted in escalating urban poverty and proliferation of slums.

 Molly O'Meara Sheehan is project director for this year's State of the World report, an annual publication of the Washington-based World Watch Institute.

Mollie O'Meara Sheehan, Project Director  for the 2007 State of the World report says the world's cities are the key to tackling poverty

"Today the best estimate is that some one billion people worldwide -- or one in every three urban people on the planet -- now live in slums, places where every day is an intense struggle for survival."

Sheehan says the city of Lagos, Nigeria, with its teeming populations and crumbling infrastructure, is a prime example. "The official municipal water supplies barely meet the demand of half the people in this megacity of ten million."

Lagos is hardly unique. Roughly half the residents of African and Asian cities lack clean water and sanitation. One point six million die each year as a result of such inadequate facilities. But national governments have been slow to respond, Sheehan says. She points out that from 1970 to 2000, urban aid worldwide totaled about $60 billion - just 4 percent of the $1.5 trillion in total development assistance. "Perhaps more troublesome is that some governments continue to regard the urban poor as problems to be ignored at best, and pushed away at worst," Sheehan says.

But the World Watch Institute analyst contends that the task of improving conditions in the world's cities is not hopeless. Sheehan says independent community groups and local governments are the new urban pioneers, initiating new policies and programs. "And they are working to show how you can build toilets, construct homes, working together sometimes with the government and, when they won't cooperate, showing the government how they can potentially cooperate as partners."

So, for example, in Karachi, Pakistan, low-income residents have taken charge of the municipal waste problem and helped to link hundreds of thousands of households with good quality sewers. Citizens in Freetown, Sierra Leone are turning to urban farming to meet their food needs. And in Rizhao, China, a project managed to install affordable solar water heaters into nearly every household.

Co-author Peter Newman launches the World Watch Institute's 2007 State of the World report at the National Press Club

State of the World 2007 co-author Peter Newman says similar efforts are evident in cities across the globe. "There is a bit of a revolution going on at a local level that is not really being picked up at the national level. People want to change their cities."

That revolutionary thinking has inspired slum dwellers to organize in more than a dozen countries. It has led mayors in over 350 U.S. cities to sign a Climate Protection Agreement and to lobby for a national climate policy.

But World Watch's new State of the World report warns that the fate of cities will depend on how effectively world governments and institutions respond to the challenges of urbanization and, in particular, the needs of the urban poor.