Adaptation of water management to regional climate change in a coastal region – Hydrological change vs. community perception and strategies

Summary

The climate scenarios of the IPCC suggest that adaptation to future climate change will be required. The North Sea Region, a marginal sea of the Atlantic Ocean between Great Britain, Scandinavia, Germany, the Netherlands and Belgium, is particularly affected due to rising sea level and a changing water balance. Water management plays a key role in sustainable management of natural and societal resources. This paper presents a participatory study of community approaches to regional adaptation to climate change. Water management adaptation options to regional climate induced changes until 2050 were developed together with stakeholders for the Wesermarsch County (Northern Germany). Available information on expected regional climate change and a modelling study on hydrological change suggested that adaptation of water management will be required until 2050. A regional stakeholder forum formulated a vision on how the Wesermarsch should look like in 2050. Following the holistic approach of collaborative planning, two stakeholder groups developed an adaptation portfolio on how urban and rural areas could adapt their water management to cope with the expected changes. Since most of the stakeholders do not want the county to undergo significant changes in terms of landscape and land use, they proposed technical measures to enforce flood protection and enhance the performance of the existing water management system. Adaptation in terms of land use change was not proposed although information on comparable examples from similar regions was available. To justify the proposed adaptation options, available information on expected climate change impacts was used selectively. Uncertainty in model projections was partly ignored to legitimate suggesting inflexible (technical) adaptation measures. However, collaborative planning proved to be helpful for a joint adaptation to climate change at the regional scale. Stakeholders as well as scientists took active part in the participatory learning process as required by EU directives.

Introduction

Climate change is one of the key issues in recent environmental research and studies on sustainable development. The Intergovernmental Panel on Climate Change (IPCC) has stated that global warming has accelerated significantly in the second half of the 20th century, and that humans have caused the dominant part of global warming (IPCC, 2007a).

Based on these commonly accepted facts, science and society are debating on how to react to climate change. Two main complementary strategies are recently suggested: (1) to mitigate a future climate change (e.g., by reducing the emission of greenhouse gases) and (2) to adapt to those changes which cannot be mitigated. While mitigation needs to be evaluated on a global scale, adaptation to climate change is a local to regional scale issue (Füssel, 2007). According to van den Hurk and Jacob (2009), ‘global mean temperature will continue to rise by approximately 0.1 °C per decade during the 21st century due to the delayed response of the slow components in the climate system even when greenhouse gas concentrations will not increase from the level reached in 2000’. Therefore, independent of the efficiency of future mitigation, an adaptation to continuing climate change is necessary if such climate change exceeds current climate variability. Adaptation to climate change, therefore, has raised public interest in the past years, mainly driven by climate related disasters (Füssel, 2007, Krysanova et al., 2010). As a consequence, preliminary national concepts have been setup towards the development of national adaptation strategies (e.g., for Germany: Bundesregierung, 2008).

Due to the increasing relevance of adaptation to climate change, the scientific community has paid more attention to this topic in recent years. Publications introduced general concepts and approaches for adaptive planning (e.g., Füssel, 2007) and analysed regional possibilities for and limitations of climate change adaptation (e.g., Kabat et al., 2005, de Bruin et al., 2009). Adaptation strategies were compared among different regions and river basins (e.g., Krysanova et al., 2010) as well as their recent status in adaptation planning (e.g., Huntjens et al., 2010). Most authors agreed that adaptation needs to be on regional scale (e.g., Wesselink et al., 2009) and consider different issues (de Bruin et al., 2009, Veraart et al., 2010) such as natural systems, agriculture, economy and water management.

Planning the adaptation to climate change requires the use of information on present and future climate conditions. Therefore, most developments of adaptation strategies or concepts are based on future climate projections. According to Füssel (2007), the effectiveness of proactive adaptation to climate change is expected to depend on the accuracy of regional climate and impact projections when following a top-down approach. The uncertainty in future climate can be one of the most important barriers for climate change adaptation (Krysanova et al., 2010). Consequently, the question that arises is how to incorporate uncertain scenarios into the process of adaptation planning (Cohen et al., 2006). Some authors argue that additional information provided by climate model ensembles and scenarios is valuable for understanding the possible ranges of future conditions. Such information might enable decision-makers to compare the (dis-)advantages of different adaptation options and their timing (e.g., Lopez et al., 2009). Other studies object that policy makers prefer to stick to one single climate change scenario (Veraart et al., 2010). Nevertheless, acceptance of uncertainty and dealing flexibility with variable projections should be one quintessence of adaptive planning. Blöschl and Montanari (2010) emphasised the uncertainty in the assessment of climate change effects. They argue that there should not be too much confidence in any simulation of rainfall–runoff driven floods in a changed climate which are mostly used as basis for the development of water management concepts. While Blöschl and Montanari (2010) do not provide alternatives, they pronounce the need for better uncertainty estimation and promote to effectively communicate any uncertainty to the end users of their simulation products (e.g., peak flows, water balance terms).

One sector which is mostly considered within climate adaptation studies is the water sector (e.g., Woltjer and Al, 2007, de Bruin et al., 2009, Lopez et al., 2009, Wesselink et al., 2009, Huntjens et al., 2010, Krysanova et al., 2010, Veraart et al., 2010). Some authors argue that climate change will only transform boundary conditions for water managers only (e.g., van Beek, 2009). On the one hand, many stakeholders as well as experts perceive water related risks (e.g., floods, droughts) as most serious impact of climate change (Veraart et al., 2010). Correspondingly, many studies conclude that a closer cooperation between water management and spatial planning is required (Woltjer and Al, 2007, Aerts and Droogers, 2009, Veraart et al., 2010). Furthermore, fresh water plays a particular role in coastal regions (Bormann et al., 2009, Veraart et al., 2010). In low lying coastal areas such as The Netherlands and Northwest Germany, water management is crucial due to the interactions between fresh water and salt water, storm tides and river floods as well as seasonal variations in fresh water availability. In terms of climate change, these regions will further be faced with rising sea levels and a likely hydrological change characterised by increasing frequencies and intensities of floods and droughts (e.g., Ludwig and Moench, 2009, Bormann et al., 2009). Based on such expectations, an adaptation of coastal water management in accordance with the European Water Framework Directive (EC, 2000), an Integrated Coastal Zone Management (EC, 2002) and Flood Risk Management Directive (EC, 2007) is urgently required. These EC documents emphasise an intense involvement of stakeholders in terms of participation and collaborative planning of management plans.

In this study, the importance of hydrological projections as well as their conceptualisation is analysed with respect to their perception by a community of stakeholders from water related sectors in the Wesermarsch County, Northwest Germany. Projections of a regional climate model are used to quantify possible future hydrological change in the region which might necessitate an adaptation of the regional water management. In the last century, the Wesermarsch County has continuously been affected by river engineering. Therefore, adaptation of water management to changing hydrological conditions has a long history since first rectification of the Weser River around the 1890s. Previous research shows that stakeholders are an indispensable part for the process of developing regional adaptation strategies (Cohen, 1997, Cohen et al., 2006, Füssel, 2007, de Bruin et al., 2009, Huntjens et al., 2010, Krysanova et al., 2010). They are already an explicit part of the implementation process of the European Water Framework Directive (EC, 2000) and recommended to be involved in the implementation of an Integrated Coastal Zone Management plan (EC, 2002) and for the implementation, review and updating of flood risk maps and plans according to the Flood Risk Management Directive (EC, 2007). Social learning processes in stakeholder networks have been proposed to be powerful in coastal issues such as water management (Walker et al., 2002, Berkhout et al., 2006, Pahl-Wostl et al., 2007) and coastal protection (Ahlhorn, 2009).

Within such a participation process, an adaptation strategy for regional scale water management has been developed by a group of stakeholders, experts and scientists in the framework of the Climate Proof Areas (CPA) project (EU Interreg IVB North Sea Region). Based on a description of the process and the results gained from the CPA project, we try to elaborate the impact of the available information on expected hydrological change on the result of the participation process in terms of adaptation options. We analyse the way how the information provided during the process was used, and we end up with conclusions on the information management within such a participation process to develop a regional climate change adaptation strategy (Fig. 1). This is the first study which analyses this context in the field of water management in Germany while Ahlhorn (2009) performed similar analyses for the coastal protection sector.