China's recent history has been marked by tremendous economic growth and dynamism as it has progressed from a modest farming society to a thriving manufacturing success in less than three decades. As China's economy continues to grow, it must now wrestle with a new emerging challenge: How will it handle the shift from a majority rural population to a majority urban one?

This question represents one of the biggest sustainability challenges of the 21st century.

The statistics speak for themselves. By 2030, at least 220 cities in China will have at least 1 million residents, dwarfing the 35 million-people cities that Europe boasts today. Many of these cities in China will be built from the ground up. Designed the right way, they will serve as a global model for the sustainable, low-carbon city of tomorrow.