Warren Karlenzig is president of Common Current (www.commoncurrent.com), a global consultancy for urban sustainability planning, policy and development. He has led urban sustainability strategy with clients including the The White House Office of Science and Technology; the United Nations; the nations of South Korea and Japan; Lawrence Berkeley National Laboratory; US Department of State; nation of China's Ministry of Housing and Urban-Rural Development (MoHURD); US EPA; State of California; Asian Institute of Energy, Environment & Sustainability; Guangzhou, China Planning Agency; the Municipality of Beijing; Ecocity Builders; the Packard and Columbia foundations, and the private sector, including Autodesk; Skidmore, Owings & Merrill; NRG and IDEO. He is co-author of the United Nations publication, the "Shanghai Manual: Guide for Sustainable Development in the 21st Century." Warren wrote the original language for one of the nation's first municipal green building ordinances (San Francisco). The former Chief Strategy Officer of SustainLane, Warren is author of How Green is Your City? The SustainLane US City Rankings.