Attempts have been made through the years to regulate the use of the oceans in a single convention that is acceptable to all nations. This effort finally culminated with the adoption of the 1982 United Nations Convention on the Law of the Sea, which has gained nearly universal acceptance since its entry into force on 16 November 1994.

The 1982 United Nations Convention on the Law of the Sea provides, for the first time, a universal legal framework for the rational management of marine resources and their conservation for future generations. Rarely has such radical change been achieved peacefully, by consensus of the world community. It has thus been hailed as the most important international achievement since the approval of the United Nations Charter in 1945.

While many institutions, some created by the Convention and others part of the United Nations system are responsible for governing areas on specific aspects of the ocean under their jurisdiction, the Convention itself remains the central instrument for promoting stability and peaceful uses of the seas and oceans. It is not, however, a static instrument, but rather a dynamic and evolving body of law that must be vigorously safeguarded and its implementation aggressively advanced.

There is where the United Nations has and will continue to play an important role as the depository of the Convention and the globally recognized forum for monitoring and reporting on all aspects related to oceans and the law of the sea.

International law, particularly the formulation of legal agreements between nations with commonly shared resources, provide a powerful tool for regulating access to those resources and for controlling activities with potentially destructive impacts on the environment.

There are several international agreements and a series of regional and national agreements which are directly relevant to the conservation of marine biodiversity.

These include agreements to regulate pollution resulting from maritime activity, control trade in endangered marine species, curb the hunting of endangered whales, protect coastal sites of universal value, trace the effects of climate change on marine ecosystems, and deal with pollution from land-based activities.

In addition, there are currently nine UNEP Regional Seas Conventions with their attendant protocols which address marine issues of particular regional importance.

The Convention on the Law of the Sea assigns the fundamental obligation and responsibility for protecting and preserving the marine environment to States, and requires them to adopt and enforce national laws and international standards to prevent, reduce and control ocean pollution. A growing number of detailed international agreements on the protection of the marine environment, as well as the utilization, conservation and management of marine resources, have been adopted under the unifying framework of the Convention. One of the most significant is Chapter 17 of Agenda 21, negotiated during the 1992 United Nations Conference on Environment and Development (Earth Summit) as a complement to the Convention. This agreement contains a programme of action for "the protection of the oceans, all kinds of seas, including enclosed and semi-enclosed seas, and coastal areas and the protection, rational use and development of their living resources".

Both the Convention on the Law of the Sea and Agenda 21 embody a new understanding, recognizing that the problems facing the marine environment are closely interrelated and cannot be tackled in isolation, but must be resolved through integrated management of resources and environmentally sound economic development. Some regional and subregional programmes have led to significant progress in the protection and preservation of the marine environment. The regional approach is extremely effective, and was the basis for the development of the UNEP Regional Seas Programme and Action Plans, as well as other regional programmes.