The United Nations Conference on Environment and Development (UNCED), popularly dubbed the "Earth Summit," brought together 117 heads of state and government in Rio de Janeiro, Brazil, on 3–14 June 1992. The product of this historic meeting, an 800-page document called "Agenda 21," set forth global measures to protect the planet's environment while guaranteeing sustainable economic growth. An important statement of the basic principles of sustainable development, The Rio Declaration on Environment and Development, was adopted by acclamation. The conference also spawned a new functional commission of ECOSOC, the Commission on Sustainable Development, which has a mandate to monitor international treaties on the environment, provide policy direction, and coordinate action within the United Nations system to achieve the goals of Agenda 21.
In addition to Agenda 21, two important conventions on the environment were opened for signature and received widespread endorsement: the Global Warming Convention, which set guidelines for regulating emissions of gases believed to cause global warming, was signed by 153 nations; and the Biodiversity Convention, which committed signatory nations to protection of endangered species and cooperation on genetic and biological technology, was signed by representatives of 150 countries. The Biodiversity Convention became legally binding in December 1993, after 30 countries had ratified it. Two important documents setting forth the principles behind the concept of sustainable development also were widely adopted at the Earth Summit: the Statement on Forest Principles, recommending preservation of world forests and monitoring of development impact on timberlands; and the Declaration on Environment and Development, a statement of principles that emphasized the coordination of economic and environmental concerns.
More than two years were spent preparing for the Earth Summit and drafting the documents that would achieve widespread international acceptance. However, many controversial propositions had to be deleted or scaled down in the final documents to achieve the final consensus. For example, negotiators removed or excluded specific targets on pollution controls, resource protection, and financial aid to developing countries that restrain their economic development in order to protect their natural resources. Developing countries had sought to establish a "green fund" to support their efforts to implement environmentally sustainable development. However, the G-7 group of industrialized countries succeeded in specifying that such development funds would be channeled through the World Bank's Global Environment Facility (GEF), effectively retaining control of funding in the hands of the industrialized world. The European Community had recommended a tax on fossil fuels in industrialized nations, but, opposition from oil-producing countries killed this provision. Also deemphasized in the final documents were references to population control. Passages referring to contraception were completely deleted at the insistence of an odd coalition that included the Holy See (Vatican), Roman Catholic countries, and Moslem countries.
The sense of urgency that brought 35,000 accredited participants and 117 heads of state to Rio de Janeiro for the Earth Summit is perhaps well summed up by the UNCED secretary-general, Canadian Maurice Strong: "The Earth Summit must establish a whole new basis for relations between rich and poor, North and South, including a concerted attack on poverty as a central priority for the 21st Century. We owe at least this much to future generations, from whom we have borrowed a fragile planet called Earth."
At the Earth Summit+5 meeting held in June 1997 in New York City, the objectives were to revitalize and energize commitments to sustainable development, to recognize failures and identify their causes, to recognize achievements (there were many Agenda 21 success stories that were highlighted during the event), to define priorities for the post-97 period, and to raise the profile of issues addressed insufficiently by Rio. In addition to assessing progress since the last meeting and outlining areas requiring urgent action, attendees called for greater cooperation and adherence among intergovernmental organizations and developed a program of work for the Commission on Sustainable Development for the years 1998–2002. The program included a comprehensive review of the program of action for the sustainable development of Small Island Developing States (SIDS), developing integrated management and planning of land resources, and developing strategic approaches to freshwater management.