ImageUrban sustainability is the challenge of the century as more of the world's population becomes urbanized (50 percent in 2008, 60 percent by 2030), at an ever-faster rate. Global climate change has been caused in large part by the burning of fossil fuels to generate energy, materials and food for metro areas. Yet urban culture also constitutes a powerful response capability by which to cope with the diminishing socio-economic options forced by climate change, especially in megacities, metro areas of more than 10 million people.

Upon this tableau, I am collaborating with the United Nations Department of Economic and Social Affairs, in conjunction with other UN agencies (United Nations Environment Program, UN Development Program, UN Habitat and UN Center for Regional Development) and the Shanghai World Expo Bureau on a sourcebook for sustainable urban management in developing nation megacities.

The sourcebook will consider sustainability advantages to urbanization along with disadvantages. It will cover broad topics including greening the urban economy, effective management, as well as solution sectors (land use and planning, water, buildings, transportation, information and communications technologies). Case studies will be provided to illustrate how solutions have already overcome a host of urgent challenges, or how they may soon be able to help do so.

With the acute rise of urbanization in developing nations, megacities will increase in both number and economic-environmental influence. As of late 2010, there were between 12 and 15 developing nation megacities (cities of 10 million population in their metropolitan areas), with 19 developing nation cities in total expected to reach megacity status by 2025. 

During the next ten years, according to the McKinsey Global Institute (pdf), 90 percent of urban population growth will take place in developing countries. In India, for example, cities are forecast to garner 85 percent or the nation's total tax revenue (up from current level of 80 percent), which will be the primary source for financing economic development on a national scale. Seventy percent of all new jobs will be created in the cities of India by 2030, though cities are expected by that date to represent only 40 percent of the nation's total population.  

In terms of impacting climate change, consider that the cities of Asia alone are expected to contribute more than half the global greenhouse gas emissions between now and 2027.

Besides the threats and risks that megacity growth poses to global humanity and regional resources, trends in developing nation megacities will also strongly define emerging economic opportunities for large-scale low-carbon and resource-efficient technologies, services and strategic approaches. Whether in Delhi or Mexico City, megacities are devising more effective methods of integrated sustainability management using everything from social networks and crowdsourcing, to paticipatory budgeting and comprehensive green planning.

Cities are the most powerful economic engines in the world for advances in information and communications technologies, health care, education and energy systems. These combined capacities have provided urban areas with anywhere from 55 percent (developing nations) to 85 percent (developed nations) of total national income, significantly surpassing per-capita income averages, and trending even more upward during the next two decades of hyper-urban growth.

Megacities and urbanization, in other words, should be the cause for global concern that needs to be tempered with concerted strategy, actions and ultimately, hope for humanity. 

The complete United Nations study is expected to be released on 1 May 2011, the first anniversary of the opening of the 2010 Shanghai World Expo-which has a theme of "Better city, Better life."

Warren Karlenzig is president of Common Current, an internationally active consultancy based in San Anselmo, California. He is a Fellow at the Post-Carbon Institute and author of How Green is Your City?: The SustainLane US City Rankings.