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Threats to the Marine Environment: Pollution and Physical Damage

Note that the linear relationship between (logged) emissions and (logged) population implies that we estimate the direct effect of population on emissions only, but not the indirect effects that might work via the impact of population on either A or T. This has been critically noted by a number of participants in the ongoing discussion about the usefulness of IPAT (e.g., MacKellar, Lutz, Prinz & Goujon, 1995). Such complex inter- action effects are beyond what can be achieved in this paper and are left for future research. Cramer (2001) is concerned about potential feedbacks of pollution on population. Of course, the direct effect is likely to be small as. | Chapter 2 Threats to the Marine Environment 23 Chapter 2 Threats to the Marine Environment Pollution and Physical Damage The oceans have always been subject to human activities. To a varying extent these activities have adverse impacts on the state of the marine environment. Detrimental environmental effects depend upon the nature of human interference with nature. Two types may broadly be distinguished pollution and physical destruction. As far as threats to the marine environment are concerned pollution is by far the more significant. It therefore forms the main focus of this chapter. Its internationally recognised definition for the marine sector was developed by GESAMP and reads Introduction of man directly or indirectly of substances or energy into the marine environment including estuaries resulting in such deleterious effects as harm to living resources hazard to human health hindrance to marine activities including fishing impairment of quality for use of sea-water and reduction of amenities. 109 In contrast to this very comprehensive definition physical damage merely comprises those cases in which a marine habitat is destroyed or degraded by direct impact. They are essentially limited to damage by groundings of ships anchorage or construction works. Consequently habitat destruction will only be addressed in relation to environmental threats from shipping. In dealing with threats to the marine environment I shall first give a brief overview of the main sources of pollution. Subsequently I will turn to the major substances that may cause pollution. With respect to the scope of this treatise in the third part of this chapter I will pay special attention to threats to the marine environment posed by international shipping i.e. operational and accidental pollution as well as habitat destruction. I. Sources of Pollution Three sources of pollution may broadly be distinguished namely coastal sources including river influx atmospheric deposition and offshore .