At the opening of the 64th annual DPI-NGO conference in Bonn, Ban Ki-Moon, Secretary-General of the United Nations, said voluntary action was one of the highest expressions of our common humanity. Looking forward to the Rio+20 United Nations Conference on Sustainable Development, he said the solution to current dangerous climate change lay in a fundamental transformation of consumption patterns and life styles. Creating a sustainable green economy that would protect the environment and help achieve the Millennium Development Goals would not be possible without the involvement of all sectors of society, he warned, and emphased that all non-governmental organizations, individually and collectively, had an important role to play.