Transboundary pollution law poses the challenge of addressing environmental problems irrespective of boundaries in an international legal system that values, above all, territorial sovereignty of individual States. Over the years, several international disputes have resulted over damage that occurred when one State’s pollutants crossed into another State’s territory. The Trail Smelter case of 1941 is considered the landmark case of transboundary pollutant litigation. In this controversy, the United States claimed that damage was caused to the State of Washington by fumes from a smelter located seven miles from the international border in Canada. The U.S. initially rejected the decision of the International Joint Commission and the case was then referred to arbitration under a 1935 treaty. In March 1941, the United States was awarded the arbitral decision which asserted the principle that a State has responsibility for any environmental damage it creates even beyond its territorial limits. Specifically, the tribunal found that based on principles of international law: no State has the right to use or permit the use of its territory in such a manner as to cause injury by fumes in or to the territory of another or the properties or person therein, when the case is of serious consequence and the injury is established by clear and convincing evidence. The Trail Smelter case underscored the fact that ecological effects know no boundaries; they can spill across geopolitical frontiers and cause cumulative externalities worldwide. Perhaps the most significant aspect of the Trail Smelter case was that it required States to do more than make reparation for environmental damage-it also recognized the duty of States to take appropriate measures to protect the environment. This case gave rise to the concept that even a sovereign nation owes surrounding States some protection from pollution which is created within its jurisdiction. The Trail Smelter case was unique in that it was one of the first cases to address an amorphous type of transboundary pollution. In fact, the Trail Smelter arbitration remains the only international adjudication on the subject of air pollution. At the time of the Trail Smelter controversy, scientists and legislators could not have anticipated the negative effects from the increasing presence of a similar, and seemingly innocuous type of pollutant-ocean noise. The effects from ocean noise are perhaps subtler and more insidious than the environmental effects of air pollution. These effects are unseen but can constitute an enormous threat to the marine ecosystem. Noise in the ocean is analogous to the smoke and noxious fumes of Trail Smelter in that it can also be considered a form of transboundary pollution. The 1982 United Nations Convention on the Law of the Sea (UNCLOS) defines marine pollution as: the introduction by man, directly or indirectly, of substances or energy into the marine environment, including estuaries, which results or is likely to result in such deleterious effects as harm to living resources and marine life, hazards to human health, hindrance to marine activities, including fishing and other legitimate uses of the sea, impairment of quality for use of sea water and reduction of amenities. Because acoustic emissions involve the introduction of energy into the marine environment and may involve deleterious effects to marine mammals, noise can clearly be considered pollution under UNCLOS. The U.S. National Academy of Sciences has stated that “noise is widely acknowledged to be an environmental pollutant for humans and many other terrestrial species, and it is no doubt a pollutant for marine animals as well.” Underwater sound is created by myriad activities worldwide. Whether it is created intentionally as in the use of sonar or as a by-product of another activity such as shipping, it is estimated that noise in the water has increased in magnitude between 1950 and 1975. The growing use of underwater acoustics for scientific research, defense applications, aquaculture, and seafloor mapping has greatly increased the quantity and intensity of sound in the ocean. This has given rise to issues that have not been addressed before. Environmental groups, biologists, and acousticians have raised concerns that man-made noise in the ocean could have adverse environmental effects on marine life. Specifically, it is believed that acoustic emissions affect the behavior of many species of marine mammals and could have effects on humans as well. Future regulation that restricts the use of sonar could have enormous impacts on naval operations, scientific research, oil exploration, fishing and aquaculture. Even unintentional emission of sound in the ocean created as a by-product of other activities such as shipping, recreational boating, and airplanes could be subject to regulation. Because underwater sound is capable of traveling long distances-thousands of miles-it can be considered a type of transboundary pollution. Presently there is a lack of a coherent policy framework for evaluating the environmental impacts of underwater noise pollution. There are no international treaties or laws that specifically address the operations of sonars or transmission of sound in territorial waters or the high seas. This paper examines the issue of underwater noise pollution in a global context and identifies the capacity of international instruments to address it. Specifically, it discusses the establishment of regional agreements and conventions that directly address underwater noise pollution. Additionally, recommendations are made for the development of appropriate policy regarding the use of sound in the ocean.

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