1 The Oceans in the Anthropocene
duced all around the Mediterranean (in France, Spain, Portugal and Italy), but also in the coastal regions of the Black Sea, Africa, India and China. It is estimated that 30 % of the world’s salt production (2009: 260 million tonnes; Lohmann, 2012: 149) is derived from seawater and salt ponds (K+S, 2013). Desalination not only produces salt, it also purifies freshwater for use in irrigation and as drinking water. Seawater is also used to cool power plants.
1.1.7 The economic value of marine ecosystems
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It is difficult to calculate the economic value of marine and coastal ecosystems. To date, the only study of the overall value of marine ecosystems – whose methodology, it must be said, is extremely controversial – is a paper by scientists who worked with Robert Costanza and is dated 1997. The study put the total value of the global biosphere at around US$ 33,000 billion per annum (at 1994 prices), of which roughly two thirds, i. e. roughly US$ 21,000 billion per annum, was accounted for by marine and coastal ecosystems (Costanza et al., 1997). Of this US$ 21,000 billion, US$ 8,400 billion was assignable to the oceans and US$ 12,600 billion to the coastal ecosystems, i. e. to estuaries, seagrass beds and kelp forests, coral reefs and the continental shelf. According to this study, the value of marine and coastal ecosystems was thus equivalent to about 80 % of global GDP at the time, which stood at around US$ 27,000 billion (at 1994 prices; IMF, 2012). Even though these numbers are based on simplified and methodologically debatable calculations, they at least give an idea of the magnitude of the value of marine ecosystem services (UNDP and GEF, 2012a). To this day, scientists assume that marine and coastal ecosystems account for two thirds of the Earth’s total natural capital (Beaudoin and Pendleton, 2012). Calculations such as those conducted by Costanza et al., 1997, also highlight the tremendous methodological challenges that confront attempts to measure the overall economic value of marine and coastal ecosystems, as not all aspects of these ecosystems can usefully be expressed in monetary terms. Examples include the nutrient cycle, the way ecosystems work and genetic resources (Noone et al., 2012). One of the problems with the estimates of Costanza et al. (1997) is that, for want of available studies, not all biomes and not all types of ecosystem services were taken into account in the overall estimate. Moreover, the studies referred to were based on the willingness of the population alive at the time of the survey to pay, while the valuations of future generations were disregarded entirely. The
findings of these studies were linearly extrapolated to the global level, which caused inaccuracies. Nor were tipping points or irreversible issues factored into the study. Lastly, it also added together different subtotals – a practice that does not do justice to the complex interdependencies between different biomes and ecosystem services. More recent studies have attempted to improve on the weaknesses of Costanza et al. (1997). To date, however, there is no topical, comprehensive evaluation of the global marine and coastal ecosystem services that also takes account of interdependencies between the different ecosystems. Few studies have yet concerned themselves with the value of marine ecosystems, and of those that do, even fewer examine deep-sea ecosystems (Naber et al., 2008). Evaluation studies exist for individual ecosystem services or biomes, especially for coral reefs, coastal ecosystems and mangroves (TEEB, 2009; Beaudoin and Pendleton, 2012). For instance, TEEB (2009), working on the basis of various studies, puts the value of coral reefs as high as US$ 1.2 million per hectare per annum. Another example is a UNEP study of the annual value of the ecosystems in the Mediterranean, whose minimum estimate came to € 26 billion for 2005. This figure includes the provision of food, recreational uses, climate regulation, the regulation of natural hazards and waste assimilation (UNEPWCMC, 2011). All these studies underscore the considerable economic importance of marine and coastal ecosystems.
1.2 Threats to the oceans The direct and indirect use of the oceans has already led to profound changes that greatly impact on the ocean ecosystem and the ecosystem services used by humanity. Moreover, trends show in many cases that the threat to the oceans caused by human activity is still growing.
1.2.1 Physical destruction of ecosystems The most striking forms of human interference with marine ecosystems relate to the physical destruction of habitats, above all in coastal areas. The factors driving this destruction include tourism, the expansion of urban infrastructure, shrimp aquacultures, and the development of ports and the dredging this involves (CBD, 2010c). According to estimates by the FAO, approximately one fifth of the world’s mangroves were