Out of 15 of the top green cities in the world Portland made it to #2
Portland, Oregon, U.S.The City of Roses’ approach to urban planning and outdoor spaces has often earned it a spot on lists of the greenest places to live. Portland is the first U.S. city to enact a comprehensive plan to reduce CO2 emissions and has aggressively pushed green building initiatives. It also runs a comprehensive system of light rail, buses, and bike lanes to help keep cars off the roads, and it boasts 92,000 acres of green space and more than 74 miles of hiking, running, and biking trails.
Check out the complete list: http://www.grist.org/article/cities3/