Half of humanity – 3.5 billion people – currently live in cities and by 2055 an estimated 75% of the world’s population will live in urban areas. Cities present the world’s population with the best chance of reducing our ecological footprint. Climate Action, the UNEP supported communications platform for global business sustainability, is launching the Sustainable Cities annual publication in June 2012 at Rio+20 – the United Nations Conference on Sustainable Development. In the run up to and during the Rio+20 conference the Sustainable Cities Blog includes the latest news and developments from around the world, and there is also a publication content overview.