At that time, this declaration was linked to the hope that deep-sea mining could possibly eradicate poverty worldwide. This expectation has not yet been realized. In principle, UNCLOS advocates the promotion of mining activities, but subject to the condition that the marine environment will be adequately protected.
The international legal requirements for mining projects are derived from UNCLOS and the 1994 Implementing Agreement. UNCLOS is a largely comprehensive set of rules and regulations of almost universal application - although the USA have not yet ratified it. According to its preamble numbers 1 to 4, it aims to clarify all aspects of the law of the seas. Most of the provisions of UNCLOS are recognized as customary international law.
The requirements under international law for mining activities on the seabed differ depending on whether they take place within or outside national jurisdiction.
UNCLOS distinguishes between certain spatial areas and defines the states’ respective rights and obligations for these areas which, primarily, comprise coastal waters, the continental shelf, the high seas and “the area”.
The territorial waters (up to twelve nautical miles, depending on the designation - UNCLOS Article 3) are part of the national territory of the coastal states with exclusive sovereignty (UNCLOS Articles 2 et seq.). In the Exclusive Economic Zone (up to 200 nautical miles) as well as on the continental shelf (generally 200 nautical miles, or further in case of corresponding natural conditions), the coastal states have the exclusive exploitation rights over natural resources, both living and non-living.
When exploring for or exploiting of mineral resources on the continental shelf, states are to comply with the requirements of Part XII of UNCLOS - "Protection and preservation of the marine environment". UNCLOS Articles 192 et seq. oblige coastal states to preserve and protect the marine environment. According to UNCLOS Article 194 (5), appropriate measures are necessary to protect and preserve rare or fragile ecosystems. According to UNCLOS Article 208 (3), national measures shall be no less effective than the internationally agreed level of protection.
In Part XI, UNCLOS refers to the seabed beyond the national continental shelf as "The Area". UNCLOS Article 136 declares "The Area" to be the "Common Heritage of Mankind". The principle of "Common Heritage of Mankind" is usually assigned five core elements. First, UNCLOS Article 137 (1) provides, similar to the high seas, for a prohibition of appropriation of the deep seabed as a whole or any part thereof. UNCLOS Article 137 (2), also applies to mineral resources as long as they are still under the seabed surface. However, according to UNCLOS Article 137 (2), sentence 2, an appropriation of mineral resources is licit if it is done pursuant to the specifications of Part XI. Secondly, UNCLOS puts the exploitation of mineral resources of “The Area” under international administration (UNCLOS Article 137 (2), sentence 2, and UNCLOS Articles 156 and 157). The ISA, based in Kingston, Jamaica, is in charge of the administration. Third, UNCLOS Article 141 calls for “The Area” to be used exclusively for peaceful purposes. Fourth, UNCLOS Article 145 stipulates that "effective protection of the marine environment from harmful effects" is to be ensured. Fifth, UNCLOS Article 140 (2) and Articles 160 et seq. provide for financial and other economic revenues and benefits be shared equitably among all states ("benefit sharing").
Since the adoption of UNCLOS in 1982, international environmental law has developed significantly. The international community has agreed on further principles, some of which are binding and some of which are not legally binding. These are: first, the principle of sustainable development; second, the precautionary principle, and third, the polluter pays principle. The principle of sustainable development calls for the integration of social, economic and ecological concerns, taking into account the interests of future generations. The precautionary principle entails that measures must also be taken in the case of gaps in knowledge if this is necessary to protect the environment. The polluter pays principle calls on the polluter to bear the costs of restoring environmental impairment.
The ISA Signatories have repeatedly declared their commitment to both the principle of sustainable development and the precautionary principle. Thus, it can generally be assumed that the ISA recognizes these two principles as binding or at least as guiding action. This does not apply to the polluter pays principle - at least not explicitly.
The basic assumption of UNCLOS is that the ISA should encourage mining activities on the deep seabed (see UNCLOS Articles 150 et seq.). This being the case, UNCLOS in principle gives a positive answer to the question of "whether" mining activities should take place. However, according to UNCLOS Article 145, this regulation is subject to the proviso that the marine environment can be effectively protected. Legally, it would therefore be possible to prohibit mining activities and also to impose a general moratorium on mining activities arguing that the impact on the environment cannot be adequately predicted due to the existing lack of knowledge.