The United Nations Framework Convention on Climate Change was adopted on 9 May 1992, and opened for signature at the UN Conference on Environment and Development in June 1992 in Rio, where it received 155 signatures. The Convention entered into force on 21 March 1994 (90 days after receipt of the 50th ratification).
Since the adoption of the Convention, the INC has met five more times to consider the following items: matters relating to commitments; matters relating to arrangements for the financial mechanism and for technical and financial support to developing countries; procedural and legal matters; and institutional matters. During these INC sessions, scientific work was done to improve the methodologies for measuring emissions from various sources, but the larger scientific problem is choosing the best methodology to estimate the removal of carbon dioxide by "sinks," namely oceans and forests. The other major task before negotiators has been to work on the difficult issue of financial support for implementation, particularly for developing country Parties who will require "new and additional resources" to obtain data and implement energy-efficient technologies and other necessary measures.