Coastal Systems under Global and Regional Pressures
We describe the past, recent, ongoing and possible future coastal changes, and identify the main driving forces.
Objectives and Challenges
Coastal systems, comprising geophysical and ecological components, are subject to permanent change, some of which is natural (e.g., changing morphology, low frequency natural climate variability) and some of which is man-made. The latter has become more and more significant in recent decades, with global climate change, exploitation, the discharge of substances into the environment, the import of alien species, the modification of coastal and estuarine waters by infrastructural works, off-shore and on-shore activities (such as tourism). Thus, a variety of pressures is acting on coastal systems, and a sustainable use of the resource "coast" requires Integrated Coastal Zone Management practices. A prerequisite for this is the knowledge on past, recent and ongoing changes, on the driving factors and on perspectives for possible future changes. The objective of this work-package is to assemble this knowledge.
This is challenging for two methodological reasons. First, insufficient data is available on change. Second, coastal systems are open, and the drivers are diverse and hardly predictable; thus the system itself can barely be predicted; instead scenarios of possible futures need to be constructed. Thus, three major challenges are identified:
- Provision of representative data and estimates of past, recent and ongoing developments when insufficient data are available. The portfolio of variables and regions (e.g. from German Bight to North Sea) needs to be extended.
- Distinction between natural variability and anthropogenic driving forces and their multiple interactions.
- Construction of scenarios of possible future developments; this needs knowledge about the dynamics of the systems, the role of different driving forces, and the options available in the future.
We will go beyond the activities of previous programmes by adding observations based on new methodologies, such as new proxies derived from mussels, geological cores, and sea ice components to our regional climate models and by using the existing toolbox in different regions, specifically in the typhoon-prone area of East Asia and in analyzing climate change in the Laptev Sea/Lena Delta Region. (TO1, WP4; TO2, WP4).
A number of analytical tools will be developed, which are needed to clarify not only the informational content of proxies but also the impacts of climate variability on regional systems. These tools relate to dissolved organic matter, suspended matter and sediments as biological filters as well as a depository and source of ecologically important substances; two new proxies representative for the development during the past decades (and longer) are derived from mussels and geological cores.
Dynamical regional models suitable for long-range transport of anthropogenic substances and for the inclusion of climatically relevant or climatically sensitive components – such as sea ice, aerosol, salinity and land surfaces – will be added to the existing regional climate models. When ecosystem models advance sufficiently, these will be added for the North Sea as well.
Analysing and modelling the past and present
We will synthesize and extend continuing studies on the long-term change around Helgoland and Sylt to give an overarching description of ecological change in the German Bight. The retrospective simulations for the North Sea region will be extended to also cover the Baltic Sea and more variables in particular salinity and temperature, atmospheric input of anthropogenic substances such as selected Persistent Organic Pollutants will be examined. New variables, such as bacterial data will be considered, if the statistical and dynamical modelling efforts can be extended to include them. The strategy developed and tested for quantitatively describing the development of the hydrodynamic conditions the North Sea (wind, currents, waves) will be applied to other coastal areas of the world, in particular to the Baltic Sea, the Laptev Sea and the Lena Delta, and exemplary to coastal areas of East Asia.
Constructing scenarios of possible futures
Using the dynamical regional models mentioned above a number of possible, plausible internally consistent futures (i.e., scenarios) for the coming decades and century will be constructed. The models will process global/continental scale climate change, available from the ZMAW in Hamburg and elsewhere, and changing regional pressures available through expert knowledge.
Analysing causes for past and ongoing change
Special emphasis will be placed upon the role of changing geophysical conditions (in particular temperature increase), of altered import of matter and run-off from catchments and atmospheric input on the functioning and composition of coastal ecosystems. We will analyse the spread of exotic species through human trade and alterations in climatic conditions, and explore the implications for ecosystem functioning and habitat properties (link to WP1). Retrospective simulations will be related to scenario simulations to determine the present role of man-made climate drivers (emissions) for ongoing regional climate change as opposed to the role of natural variability. Regional case studies for Northern German coastal areas will explore the range of options required to adapt and locally mitigate undesired and detrimental consequences of regional change, as envisaged by the scenarios mentioned above. Also the possible implications for global scale change will be assessed.
- Synthesis of Long-Term Ecological Change in the North Sea and Wadden Sea (year 2/3)
- Model system for climate reconstruction 1960-today for Laptev Sea up and running; coupling of long-range transport module with regional climate model done; hydrodynamic model of the Baltic Sea up and running (year 2)
- Reconstructions of past climate (1960-today) for Laptev Sea and E. Asia (year 2/3)
- Regional Climate Change scenarios for the North Sea, Baltic Sea, East Asia and Laptev Sea available (year 4)
- Completion and synthesis of the studies on long-term ecological change in the German Bight as a basis for an assessment of the Status and Change in the North Sea
- High-resolution reconstructed data sets and climatologies of temperature, wind, ocean waves and storm surges in the arctic coastal region (Laptev Sea/Lena Delta) and other regions
- Scenarios of coastal change caused by anthropogenic global climate change, regional developments and eutrophication effects
- Contributions to the 5th IPCC Assessment Report, the Quality Status Report of the Wadden Sea and the North Sea, and to the EU Water Framework Directive and the Climate Change Assessment report for the North Sea (Topic 4)