Possible new uses 1.3
Very Low Impact (<1.4)
Medium Impact (4.95–8.47)
High Impact (12–15.52)
Low Impact (1.4–4.95)
Medium High Impact (8.47–12)
Very High Impact (>15,52)
Figure 1.2-8 Cumulative impact of human activity on the oceans. The figure shows an index based on both the strength of anthropogenic driving factors and their (assumed) impact on existing ecosystems. 17 different anthropogenic drivers and 20 ecosystem types are taken into account. In the study the index ranges between values of 0.01 to 90.1. These were categorized by the authors. Figures over 15.52 are classed as indicating a very strong impact of humanity, figures below 0.14 as indicating a very weak impact. Source: Halpern et al., 2008
of stress factors, with local cumulative effects combining and overlapping with global effects. This mixture generates interactions that could lead to regional or even global tipping points in the ocean systems being reached (Scheffer et al., 2001). An international expert workshop on the threats to the oceans puts it as follows in its final report: “This examination of synergistic threats leads to the conclusion that we have underestimated the overall risks and that the whole of marine degradation is greater than the sum of its parts, and that degradation is now happening at a faster rate than predicted” (Rogers and Laffoley, 2011). This could result in the loss of marine species and entire ecosystems within decades. If no corrective action is taken, humanity could trigger the next globally significant species extinction in the oceans through the combined effects of climate change, overuse, pollution and the destruction of ecosystems (Rogers and Laffoley, 2011). However, it is almost impossible to predict the cumulative or synergistic impacts of different anthropogenic stress factors working in parallel in the oceans by means of existing ecosystem models (Boyd et al., 2010). Much more research is also needed to enable a better assessment of possible tipping points in the various marine ecosystems. What is beyond doubt is that a change of mentality
– and above all action – is urgently needed if the largescale loss of marine ecosystems and ecosystem services is to be avoided. Some positive trends already exist (in fishery, for instance; Section 4.1) proving that better management can achieve a turnaround towards an environmentally compatible, sustainable use of the oceans.
1.3 Possible new uses In addition to present-day uses, new, future technologies and ocean uses are emerging which on the one hand may pose additional challenges for the protection of the oceans, but on the other offer opportunities for their sustainable use.
1.3.1 Renewable energy At present, the renewable energy generated on or in the sea still only makes a marginal contribution to global energy supplies (Section 1.1.5). The oceans are the biggest solar collectors in the world and absorb approx-
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