On 4 October 1991 the Protocol on Environmental Protection to the Antarctic Treaty was adopted and opened for signature by the Antarctic Treaty Parties in Madrid. Coming after two years of negotiations, this instrument with its attendant five annexes represents one of the most comprehensive multilateral environmental agreements yet promulgated. It embodies a legal blueprint for protection and preservation of the Antarctic. No less important, the Protocol also signals a profound shift – indeed a reversal in course – in Antarctic Treaty Consultative Parties' aspirations for the Antarctic. In the late 1980s the policy direction of the Consultative Party group still appeared headed towards possible exploration and potential exploitation of Antarctic minerals. By 1991, however, that course had been diverted toward a general commitment of legal obligation to protecting and conserving the continent and its circumpolar seas.

A critical aim of the Protocol is to prevent marine pollution in the Antarctic Treaty area. This chapter examines how and to what extent the Protocol contributes to the general international law against marine pollution as applied in the Southern Ocean. To that end, the first section of the chapter briefiy considers how marine pollution occurs in the Antarctic, and what legal framework is already in place for dealing with it internationally. The second section assesses the Protocol as a legal instrument for preventing marine pollution. Particular attention here is given to the innovative anti-pollution qualities of the Protocol, its obligatory characteristics and its enforcement capabilities.