Approaches and policy steps

Most marine environmental problems from land-based activities are cross-sectoral in origin. So are their solutions. For example, the problems of eutrophication and sedimentation of near-shore ecosystems are linked both to rural land-use and to urban and industrial waste. In many cases problems offshore can also be linked to problems on land. For example sedimentation is closely linked to destruction of habitats, losses of topsoil and desertification. Efforts to reduce sedimentation or eutrophication will only be effective if they address all possible sources. These same efforts, however, can often be linked to other ongoing initiatives on land and in the oceans.

In a similar manner, measures to address one problem may further help to address other problems. Sewage treatment typically removes some toxins as well as nutrients, while efforts to manage the physical alteration of habitats will not only keep soils stable and reduce nutrient flow, but may help to reduce the loss of toxic agricultural effluents to rivers and streams.

There are advantages to developing a cohesive and cross-sectoral policy to address these problems, and indeed single sector efforts in many cases will not be enough. For example UN marine scientists doubt that removal of sewage and fertilisers will fully reduce nitrogen inputs. They suspect that only radical changes in transport patterns and energy-use will cut back the flows significantly. It thus remains critical for governance at levels from local to national to international to develop a coherent and comprehensive policy to address all of the problems facing waste in the oceans.