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Coordinator: H. von Storch

Overarching Questions

This RA addresses the impacts of variability and of change in large-scale climate (e.g. North Atlantic) on the local (1-20 km) and regional scale (20-1000km). Here, the regional and local systems are mainly viewed as being constrained by the large scale (North Atlantic) climate – in the spirit of “downscaling” – while specific “upscale”-influences of the European region on the large-scale weather dynamics are considered to be negligibly small. Climate impacts are seen as a function of the changing probability of events (such as storms, extended calm periods) but also as a function of the changing vulnerability related to changing human usage of natural resources and to trajectories of social and technological innovation. Thus, the changing climate scenarios need to be matched by scenarios of other regional and local drivers for instance fishery and agriculture policies.

The geographic domain of this RA is, mainly the greater North Sea Region with activities focused on resolving the dependency of significant components of the region (e.g. marine ecosystems, forestry as well as industrial, recreational and population use) on large-scale climate conditions. These components comprise the regional and local weather, also in urban conglomerates such as Hamburg, wind force, sea state, storm surges, soil quality loss, rainstorms the hydrodynamics of the North Sea, marine and terrestrial ecosystems, the flow of matter including water, sediments and anthropogenic chemicals.

The overarching research questions addressed in RA-D are

• How does climate variability and climate change impact upon marine and terrestrial ecosystems, fluxes of matter and urban structures on the regional and local scale?
• What potential risks to society occur due to these changes?
• How may the manifestation of these risks change in the short, medium and long term?
• How may climate impact change in the foreseeable future?

Five major issues are presently addressed with high scientific standards by the various partners from the University of Hamburg, the Max-Planck Institute for Meteorology and the Institute for Coastal Research of the GKSS Research Centre, and are worth to be extended in the future: Geohazards (e.g., wind, water level, sea state, precipitation and run-off), terrestrial ecosystems (forests and soils), marine systems, social systems (vulnerability, security), and urban systems.

Goals and Methods of RA-D

The joint goal of activities is to develop capabilities to estimate the effect of variability and future change of climate conditions on the various components of the regional Earth system. Most of the activities in RA-D are “applied” in the sense that they try outline options and limitations for sustainable and rationale management and suitable adaptation measures. Key methods comprise the usage of models of regional Earth system and its components (including ecosystem and biogeochemical cycles), regional and local analyses and DKRZ-scenarios as well as long-term datasets from existing monitoring and analysis programs.

In the following we sketch the goals and methods of the five RA-D issues listed above.

Geohazards – Wind, Water Level, Sea State Precipitation and Run-Off

• Geo-risks such as wind force, ocean waves and storm surges as well as rainstorms are significant in the greater North Sea region. These risks are in principle predictable, if the large-scale steering level is known. Because of the geographical detail of the costal zone, with for example barrier islands, estuaries, successive downscaling steps are needed, and accomplished via cascading grid resolutions or explicit transfer functions. Dynamical models needed for this purpose are available, but require ongoing improvement in order to better represent processes and geographical detail.
  
• An unresolved problem remains the quantification of regional changes in mean sea level, in particular, their deviations from the global mean. While the time period covered by satellite data is relatively short, tide gauge data are often affected by local effects such as construction work. For the North Sea, the data situation is relatively good. Efforts are underway to quantify the relevant terms in the sea level equations, in particular by filtering out local effects by combining observation and hindcast data from dynamical model simulations.
  
• Changes in the hydrological cycle influence precipitation regimes as well as river run-off. Such changes impact water availability (droughts), which is important for many sectors like energy, agriculture, tourism and infrastructure/transport on rivers. Changes in heavy precipitation events might cause flooding and land slides. The impact of hydrological events may be modified by regional and local conditions (vegetation, urban settlements), so that the interaction of regional and local land use with the water cycle needs to be addressed.

Terrestrial Ecosystems – Forests and Soils

• The native tree species in our forests have adapted to the local climate, atmosphere and soils over many years. Research is done to understand of how changes to the natural environment influences forests in the future. Projections of future changes to tree survival and growth and forest ecosystems health and vitality are constructed.
  
• Soils are the most important interface for processes between the atmo-, hydro, litho- and biosphere. Soils have multi-functions for the living base of humans. The Soil-Forest-Field Lab will serve as a local laboratory and case study in the “Kattinger Watt”. The interdisciplinary research is concentrated i) on scenarios of water level rise by a controlled big field experiment under in situ condition in cooperation with the local forest authorities, and ii) on trace gas fluxes forced by soil microbial processes.

The Marine Systems

• Ocean - Shelf fluxes of a variety of properties (i.e. momentum, heat, freshwater, and dead and live matter) are still poorly understood. Decadal simulations of the ocean-shelf exchange with a coupled physical-biogeochemical model are suitable tools to estimate the variability in physical, biological and biogeochemical parameters for the NW European shelf and parts of the North Atlantic. Special emphasis will be laid on the transition zone, the dynamics of which can be simulated by advanced numerical methods available in the consortium. These simulations will help understand the variability in physical, biological and biogeochemical parameters, and to identify the most sensitive components of the system to climate change.
  
• Climate change drives changes in the fluxes of materials in coastal oceans, in particular nutrients and pollutants. Eutrophication due to anthropogenic activities is a major ecological problem impacting upon the environmental status of coastal oceans. The North Sea, a well-studied example, has seen a tripling of nutrient loads since the 1950´s. Reacting to rising nutrient discharges and expected environmental deterioration, countries bordering the North Sea agreed to reduce nutrient discharges by 50% to re-establish a status approaching that of the pristine North Sea. Major scientific challenges are to define that pristine status, to quantify natural variations, and to assess carrying capacities for loads and changes in nutrient element ratios. This entails identification and quantification of nutrient sources and sinks under both pristine and impacted conditions. Clarification of natural variability and critical rates and thresholds are pursued by a combination of empirical research and numerical modelling.
  
• Marine ecosystems and their services (e.g. fisheries and the sequestration of greenhouse gas materials) are heavily impacted by changes in climatic forcing. Critical for predicting and mitigating the effects of climatic forcing on marine ecosystems and their services is an improvement of the parameterisations employed in our existing modelling and management frameworks as well as the establishment of causal relationships via the analyses and extension of existing databases on climate, populations and their interactions. These insights will allow building climate-ecosystem models suitable to support decisions by national and international agencies as to management of marine ecosystems and their services.

Social Systems – Vulnerability, Security

• Changes in vulnerability depend on trajectories of social and technological innovation and on effective forms of risk communication. Variation in innovation systems can be identified at several levels, allowing for downscaling from national to regional levels. Institutional regimes and governance structures influence the adaptation capacities of social systems. Established patterns of science-policy interactions are important channels through which risk perception and communication is formed. These social science concepts can be used to develop typologies that can feed into long-term monitoring data.
  
• Coastal zones are regions of dense interaction between natural and socio-economic changes. Regional vulnerabilities and dynamics depend on risk perception of social systems and their adaptive capabilities. Severe science gaps exist in the analysis and evaluation of impacts of climate changes and geo-risks related to regional economic, socio-demographic and cultural systems and different spatial structures like agricultural land-use systems or urban and port areas. Referring to the LOICZ science plan we contribute to following research questions: Which regional risks (will) arise from socio-economic and natural change due to the intensity and predictability of climatic and human forcing of global change? What are the time lags between predictability of risks and processes of regional adaptation and mitigation? What are political, economic, cultural and social incentives or barriers for stakeholder involvement and participation?
  
• International security: The various impacts of climate change as found in other the major research areas (geo-risks, terrestrial, marine and urban systems) are translated in socially relevant consequences, which are projected on a political map. This will allow investigating the implications on international security (migration across borders, potential conflicts caused by regionally uneven distribution of scarce resources, etc.) and possible conflicts from non-compliance with international agreements (e.g., Kyoto Protocol, Biodiversity Convention)

Urban systems

• Cities as highly sophisticated technical artefacts show a strong vulnerability to the effects of climate change. The special characteristics of cities (thermal and radiative properties, flow resistance, anthropogenic emissions) produce a distinctive urban climate with direct impact on human health and comfort, resource consumption and local economics. The prevailing impacts of climate change on urban regions are short-term (heat waves, ozone episodes) and mostly local (severe storms). Using our advanced dynamical models, the RA addresses the following questions: To what degree is climate change in urban areas caused by global/regional climate change and to what extent is it ‘home-made’? To what degree can urban climate change be mitigated or even manipulated by urban modifications? What are the implications for future town planning, local architecture, and urban governance?

 

Relations with other RA's

This RA depends strongly on knowledge and products provided by the other RAs. Specifically, analysis of ongoing variability and change both on the large-scale as well as on the regional scale are required (RA-A). The degree of predictability of environmental change as well as realistic scenarios of possible and plausible futures are provided by RA-B. The dynamical character of links between large-scale change and regional change will be examined jointly with RA-C.

Participating Researchers

1. UniHH: K. Fraedrich, H. Schlünzen, M. Schatzmann, B. Leitl (Meteorological Institute), J. Backhaus, D. Stammer (Institute for Oceanography), A. Engels (CGG), J. Oßenbrügge (Institute for Geography), M. Köhl (Centre for Forestry and Forest Products), K. Emeis (Institute for Biogeochemistry and Marine Chemistry), M. St. John, A. Temming (Institute of Hydrobiology and Fishery Science), E.-M. Pfeiffer (Institute of Soil Science), M. Kalinowski (ZNF)
   
2. MPI-M: D. Jacob
3. GKSS Research Centre: H. von Storch, R. Ebinghaus, R. Weisse