Cities are hubs of global change, andtheir global influence continues to grow. Cities contributesignificantly to global challenges like climate change andbiodiversity loss. At the same time, cities experienceimpacts like climate change first and with greatestintensity. Further, cities are becoming leaders worldwide inefforts to address global environmental and social problems.Some of the most important smaller-scale agreements andpartnerships emerging from Rio+20 (the United NationsConference on Sustainable Development) were initiated by orfocused on cities. Even as the conference reinforced theincreasing difficulty of reaching consensus on globalchallenges, it also saw smaller-scale agreements andpartnerships emerge. Some of the most important"microagreements" focused on cities.