The document summarizes key details from several United Nations Earth Summits focused on sustainable development and the environment, held between 1992 and 2012. The main summits discussed were the 1992 Rio Summit, where agreements were reached on Agenda 21 and the Rio Declaration; the 2002 Earth Summit in Johannesburg; and Rio+20 in 2012. Key outcomes included frameworks and conventions on climate change, biodiversity, desertification, and commitments to achieve Millennium Development Goals.