SUD-Net and its partner Cities and Climate Change Initiative (CCCI) recognize the vital role of communities in both the contribution to and the mitigation of climate change. It is a growing public concern and in the 1990s became an issue of policy at the Rio Earth Summit. In order to evaluate urban contributions and efforts to ameliorate their relationship with the natural world, these concentrated centers of population have had to learn how to plan, implement, and measure the successes and failures of their respective projects.