River catchment–coastal sea interaction and human dimensions

The regional or local perspective of coastal change becomes increasingly important when coastal people are recognised as an integral part of the system. As pointed out in this journal (Cramer 2002), the key to improved interdisciplinary science of global change is not only to provide answers to the crucial Earth-system questions at a global scale. We also need to identify meaningful ways to look at the human environment and its changes at scales that are appropriate to identify choke and switch points for system functions, and where institutional settings enable action to be taken as a societal and policy response. For coastal zones, three major challenges need to be met by an appropriate and flexible scientific approach to this problem (cf. Kremer et al. 2002). First, the time delay between changes in land-based material flows (due to socioeconomic activities, morphological changes or regulatory measures) and their impact on the coastal zone system must be determined. Second, the complexity of the coastal sea environments needs to be investigated in order to derive assessments of ‘critical loads’. Third, multiple interests and stakeholder needs must be studied, as they are affected by transboundary issues, particularly when local, regional, national and multinational governmental bodies have conflicting interests. The Land-Ocean Interactions in the Coastal Zone (LOICZ) core project of the International Geosphere and Biosphere Program (IGBP), after 10 years of collaborative global research, has made an effort to follow this direction. Its ‘Basins project’ (http://w3g.gkss.de/projects/loicz_basins/) has, since 1999, tried to provide a first-order global assessment of key land-based processes that affect coastal zones. Regional scientific networks have been established to look at the drivers, pressures, state changes and the impact on coastal systems by applying a scale that considers the catchments and coasts as a single interrelated system: the water continuum. The relevance of this scale had been highlighted by Meybeck (1998, 2003) to emphasise the multiple boundaries and processes through which land-based drivers affect the water cycle and the global coastal ocean. However, regional expert typologies of this ‘river dimension’ of coastal change and subsequent upscaling to subregional and continental scales, as performed in the Basins project, had been lacking. Recently, policy and global assessment efforts hosted by, for example, UN Programmes such as UNEP and UNESCO, have adopted this approach to programs such as the Integrated Coastal Area and River basin Management (ICARM) initiative under the Global Program of Action for the Protection of the Marine Environment from Landbased Activities (GPA), and to efforts that deal with global monitoring in coastal zones, e.g., Coastal GOOS (Global Oceans Observing System). Coastal themes are under development for initiatives that deal with regular Earth Observation such as IGOS, and practical management has recognized the catchment scale of coastal change in some of the most recently launched regional ‘institutions’, i.e. the European Water Framework Directive (Directive 2000/ 60/EC, L 327/1 Brussels, 23 Oct. 2000 and Ledoux et al. 2004) and the EU recommendations concerning the implementation of Integrated Coastal Zone Management in Europe (2002/413/EC, L 148/24, Brussels 30 May 2002). Recent research reflects the relevance of the water-continuum scale for integrated modeling and forecasting, and also for policy advice. Examples are projects such as the EU-funded EuroCat (http://www.iia-cnr.unical.it/EUROCAT/project.htm), daNUbs (http://danubs.tuwien.ac.at/) and Catchment2Coast (http://www.catchment2coast.org/), which study coastal change in a regional perspective in Europe and Africa. The ‘New’ LOICZ, mandated to provide an integrated view on coastal systems and human-initiated-change issues to the Earth System Sciences in the coming decade (2003–2012), has given the water-continuum scale of coastal change a priority position among the themes that will guide its scientific agendas in the future (see the ‘New’ LOICZ draft Science Plan and Implementation Strategy and subsequent information under http:// www.loicz.org). Its ‘‘Anthropogenic influences on river basin and coastal zone interactions’’ theme, as well as the other three themes (Fig. 1), will contribute to the key question on ‘‘what determines the vulnerability of coastal systems and human safety’’ all of them being embedded in Published online: 17 February 2004 a Springer-Verlag 2004