Climate adaptation policies for the coastal zone

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Coastal adaptation policy cannot be based on a single prediction of future climate conditions or on a fixed set of measures. It should identify measures that are appropriate under present conditions while keeping open options for responding to different future developments. This requires long-term scenarios, adaptation pathways, monitoring of changing conditions and advance preparation for decisions that may become necessary later.

This article should be read in conjunction with the Coastal Wiki articles Climate adaptation measures for the coastal zone and Integrated Coastal Zone Management (ICZM). The important issue of climate adaptation in coastal cities is dealt with in a separate article Coastal cities and sea level rise. Parts of the present article are based on a paper by Dronkers and Stojanovic (2016[1]).



Urgency of climate adaptation

Climate change, and sea level rise in particular, is a major threat to many coastal zones [2] (see also the article Sea level rise). Many low-lying coastal areas, especially delta plains and small islands, are already exposed to flooding, erosion, salt intrusion and other climate-related hazards. Continued sea level rise will progressively increase these pressures, while changes in storm climate, precipitation and temperature can further alter coastal risks (Mentaschi et al., 2017[3]; Metel et al., 2018[4]). In many regions these impacts interact with land subsidence, water shortage and continuing development of the coastal zone (Deltares, 2015[5]), which is further exacerbated by fast population growth (Barragan et al., 2015[6]), see the article Coastal cities and sea level rise. Measures for dealing with the impacts of climate change in these coastal zones are already urgent today (Wong et al., 2014[7]). Such measures interfere with other developments and interests in the coastal zone and should therefore be embedded in an ICZM strategy.

Although the magnitude and timing of future impacts are uncertain, continued climate change and sea level rise are among the more certain long-term developments that coastal societies will have to face. Adaptation can therefore not simply be postponed until future conditions are known with greater certainty. This does not imply that all adaptation measures required in the distant future should be implemented now. It does imply that present policies should anticipate increasing climate impacts and avoid decisions that unnecessarily restrict the adaptation options available in the future. Climate adaptation should therefore be embedded in an ICZM strategy.


Uncertainty and awareness

Countries with low-lying coastal zones will increasingly have to adapt to climate change, and some impacts are already occurring. However, it is often difficult to distinguish climate-change impacts from changes caused by natural variability or other human activities. Uncertainty about the magnitude and timing of future impacts can therefore hamper public awareness and make it difficult to give climate adaptation political priority over issues with more immediate and visible consequences[8].

A further obstacle is that the most severe climate-related impacts are often associated with exceptional extreme events rather than with everyday experience. Such events can therefore strongly influence public and political perceptions of climate risk. A survey among European policymakers found that extreme weather events were the most important trigger for progress in climate adaptation[8]. This points to a fundamental difficulty of anticipatory adaptation: major adaptation measures are often initiated only after an extreme event has demonstrated the risk, while timely adaptation could have reduced the resulting damage.

Risk-based adaptation

The largest climate change impacts in the coastal zone result from extreme events which have a low probability of occurrence within a given time interval. Risk assessment provides a systematic basis for comparing climate impacts and adaptation options by considering both the likelihood and consequences of damaging events (see Vulnerability and risk). It does not by itself determine which level of risk is acceptable, as this also depends on societal preferences and policy objectives.

By evaluating which damage is avoided at which costs, informed choices can be made among different adaptation strategies. Uncertainty in the probability of occurrence and uncertainty in the estimated damage can be incorporated in a risk assessment[9]. If probability distributions can be defined for the various factors influencing occurrence and damage of extreme events, a Monte Carlo method can be used for the risk assessment (Pappenberger et al., 2006 [10]). The application of the risk concept in adaptation strategies is limited, however, by the difficulty to estimate these probability distributions, especially regarding possible damage and loss of life caused by rare extreme events [11].

A further complication arises when a choice has to be made among different possible adaptation measures: which time scales and spatial scales have to be considered ? The choice of these scales strongly influences the outcome of ranking methods (based, for example, on cost-benefit analysis, cost-effectiveness or multi-criteria analysis). This complication is enhanced by the uncertainty about the future in general. How are values of present assets affected by other future global or local changes, in addition to climate change, and how do societal interests evolve? The conjugation of these different sources of uncertainty is sometimes called “deep uncertainty”[12]. Hardest to deal with are the so-called 'unknown unknowns': the things we don't know we don't know (Rumsfeld (2002[13]).

Scenarios

It is very likely that sea level rise will go on for a long time [14]. However, climate change is only one of the major changes that will shape the future coastal zone. By the time the full effects of sea level rise become manifest, society may differ greatly from today as a result of demographic, economic, technological, institutional and cultural change. These developments will influence where and how people live, which assets and values require protection, which adaptation technologies are available and which adaptation measures are considered socially acceptable. Their long-term evolution cannot be predicted with confidence.

Long-term adaptation strategies should therefore not be designed for a single assumed future society. Scenarios can be used to explore different combinations of climatic and societal development without requiring that probabilities be assigned to them. Their purpose is not to predict the future, but to examine whether present decisions remain appropriate under widely different plausible futures and, in particular, whether they preserve options for future adaptation.

Scenarios provide a way to deal with limitations related to quantifying uncertainty (the probability that a damaging event will occur) and to quantifying possible damage (loss of human lives, loss of assets and loss of other values). Scenarios describe the various futures that can be imagined [15]. These scenarios should be internally consistent, but they are not necessarily expressed in terms of probability and money. Their main function is to open the views of those who are involved in climate adaptation to the broad spectrum of situations and adaptation options that should be considered. Scenarios help avoiding suboptimal sector approaches and a one-sided focus on certain adaptation options in current coastal adaptation strategies. However, scenarios do not answer the question which adaptation strategy among different options should be preferred.

Adaptation pathways

Fig. 1. Steps of the Dynamic Adaptation Policy Pathways approach. From Haasnoot et al. (2013[16]).

There is general agreement that adaptation to the impacts of climate change is inevitable and that preparatory actions should already be initiated. But once it becomes clear that a fundamental revision of present coastal policies is needed, the question arises which actions are most appropriate for coping with the impacts of climate change in the long term. Revised policies have to deal not only with the uncertainty related to the future impacts of climate change, but also with uncertainties related to future social, economic and technological developments. A static plan is inadequate, as the future can unfold differently from what is anticipated. An adaptation action remains effective only as long as it meets the specified policy objectives (often expressed in terms of specified risk levels). Changed climatic or socioeconomic conditions may eventually cause these objectives no longer to be met; such conditions are called adaptation tipping points (ATP)[17]. Actions that are appropriate for the foreseeable future then become inadequate and may even hinder actions that may become necessary.

One way to deal with this problem of “robust decision making” is the strategy of Dynamic Adaptation Policy Pathways (Haasnoot et al., 2012[18]), see Fig. 1. According to this strategy, adaptation pathways are developed that consist of different sets of successive adaptation actions. Each step of such a pathway may is designed to lead to successful long-term adaptation within a particular scenario of climate change, socio-economic and technological development. The analysis of the different pathways helps identifying short-term actions that perform satisfactorily under different scenarios while avoiding adverse lock-in effects. The most promising actions are those with the best performance in terms of societal benefits and costs. The steps of pathway definition and analysis is repeated when new follow-up actions become needed; the lessons of the first actions (according to “learning-by-doing”) as well as the newest knowledge of climate change, socio-economic and technological development serve as input. A refined version of this approach (“strategy of dynamic adaptive policy pathways”) has been used to support the Dutch Delta programme for adaptation to climate change (Haasnoot et al., 2013[16]). A similar method has been developed by Sayers et al. (2013[9]) and applied to the Thames estuary (McGahey and Sayers, 2008[19]). For an effective implementation of the adaptive pathways strategy, it is essential that

  • Development projects that can significantly influence future adaptation options should be evaluated for their compatibility with the long-term adaptation strategy.
  • Conditions that affect the objectives of the adaptive strategy are monitored.

Adaptive pathways provide a strong conceptual framework for climate adaptation policies. However, operational implementation is not straightforward because it can be difficult to define robust and directly measurable conditions for deciding when a change in adaptation strategy is required.

Feasibility of an anticipatory relocation strategy

With ongoing sea level rise, the risk to seaside settlements may eventually exceed a socially or economically acceptable level. Decisions about the adaptation pathway should therefore be prepared well before this threshold is reached. If accommodation is not viable, the main alternatives are structural coastal defense measures (construction or reinforcement) or relocation of property at risk.

Anticipatory relocation of well-established settlements is difficult because it raises major social, cultural, legal, financial and governance issues. It is likely to be controversial and its preparation and implementation can take many years. Governments generally find it politically easier to respond after a disaster than to implement anticipatory relocation before severe impacts have occurred[20]. For this reason, the institutional and societal conditions for relocation should be established long before relocation becomes unavoidable.

This requires clear agreement on decision-making responsibilities across the different levels of government and arrangements for fair and equitable compensation for property loss and damage. Public participation and community engagement should start at an early stage. They are essential for developing a shared understanding of (1) the data and models underlying changing risk projections and the associated risk thresholds and trigger points, and (2) why alternative strategies, such as coastal defense structures, may not provide a cost-effective means of ensuring long-term safety and may even increase long-term risks. Because local governments can be particularly exposed to pressure from groups defending short-term interests, sustained support and involvement from higher levels of government should be ensured throughout the process[20].

Mainstreaming climate adaptation

Mainstreaming climate adaptation means that actors in all policy areas that affect the state of the coastal zone are permanently aware of the consequences of climate change and adjust their policies accordingly. Climate adaptation should become a natural component of relevant current policies, at national level, at regional level and at local level. Policy measures are tested for robustness in relation to climate change and adapted to better anticipate the consequences of climate change.

Climate adaptation is an essential component of Integrated Coastal Zone Management and must be part of the policy cycle for the implementation of ICZM:

Climate adaptation plan => Implementation => Monitoring => Evaluation => Plan revision => Implementation => Monitoring => Evaluation, etc.

following the same lines as discussed in Integrated Coastal Zone Management (ICZM).

Knowledge, monitoring and evaluation

Adaptation efforts benefit from iterative risk management strategies due to the complexity, uncertainties and long-term developments related to climate change[21]. Such an iterative risk management strategy involves a continuing process of monitoring, research, evaluation, learning and innovation. Addressing knowledge gaps through improved observation and research reduces uncertainty and helps to design effective adaptation and risk management strategies.

Monitoring is essential for understanding how climate change affects the coastal and marine zone and for evaluating the effectiveness of climate adaptation policies. A coordinated and consistent approach to long-term coastal and marine monitoring is needed to detect trends against the background of natural variability and other human-induced changes. The variables to be monitored depend on the characteristics of the coastal system and the climate impacts of concern. Analysis of the observations should aim at establishing cause-impact relationships and assessing the contribution of climate change and other drivers to observed changes.

Monitoring is also needed to evaluate whether adaptation policies and measures achieve their stated objectives. This requires objectives that can be related to observable or otherwise quantifiable conditions. Appropriate indicators therefore depend on the objectives of the particular adaptation policy; there is no generally applicable set of indicators for climate adaptation. Monitoring results can reveal whether assumptions underlying the adaptation strategy remain valid and whether the strategy needs to be reconsidered.

Monitoring data are often not directly suitable for policy evaluation; translating data into indicators pertinent to policy making is a further subject of special attention. Various examples are given in the literature, for instance by Breton (2006)[22] and Marti et al. (2007)[23]), see Integrated Coastal Zone Management (ICZM) (Table 2: Measurable ICZM indicators proposed by the DEDUCE project). Appropriate indicators and, where possible, quantitative targets are important for assessing progress in climate adaptation, informing policy and the general public and strengthening the adaptive capacity of institutions and wider society.

Climate adaptation measures

The choice and implementation of specific adaptation measures are discussed in Climate adaptation measures for the coastal zone.

Financial instruments for climate adaptation

A separate article provides an overview of some important Financing climate adaptation.


Related articles

Climate adaptation measures for the coastal zone
Integrated Coastal Zone Management (ICZM)
Coastal cities and sea level rise
Sea level rise
Setback area
Financing climate adaptation


Further reading

CoastAdapt website

References

  1. ↑ Dronkers J., Stojanovic, T. 2016. Coastal Management and Governance. In: North Sea Climate Change Assessment (Editors F. Colijn, M. Quante), Springer Verlag: 475-488
  2. ↑ IPCC, 2019. Summary for Policymakers. In: IPCC Special Report on the Ocean and Cryosphere in a Changing Climate [H.-O. Pörtner, D.C. Roberts, V. Masson-Delmotte, P. Zhai, M. Tignor, E. Poloczanska, K. Mintenbeck, M. Nicolai, A. Okem, J. Petzold, B. Rama, N. Weyer (eds.)]
  3. ↑ Mentaschi, L., M. I. Vousdoukas, E. Voukouvalas, A. Dosio, and Feyen, L. 2017. Global changes of extreme coastal wave energy fluxes triggered by intensified teleconnection patterns, Geophys. Res. Lett. 44: 2416–2426
  4. ↑ Melet, A., B. Meyssignac, R. Almar and G. Le Cozannet, 2018. Under-estimated wave contribution to coastal sea-level rise. Nature Climate Change, 1.
  5. ↑ Deltares, Sinking cities https://www.deltares.nl/app/uploads/2015/09/Sinking-cities.pdf
  6. ↑ Barragan, J.M. and de Andres, M. 2015. Analysis and trends of the world's coastal cities and agglomerations. Ocean & Coastal Management 114: 11-20
  7. ↑ Wong, P.P., I.J. Losada, J.-P. Gattuso, J. Hinkel, A. Khattabi, K.L. McInnes, Y. Saito, and A. Sallenger 2014. Coastal systems and low-lying areas. In: Climate Change 2014: Impacts, Adaptation, and Vulnerability. Part A: Global and Sectoral Aspects. Contribution of Working Group II to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Field, C.B., V.R. Barros, D.J. Dokken, K.J. Mach, M.D. Mastrandrea, T.E. Bilir, M. Chatterjee, K.L. Ebi, Y.O. Estrada, R.C. Genova, B. Girma, E.S. Kissel, A.N. Levy,S. MacCracken, P.R. Mastrandrea, and L.L. White (eds.)]. Cambridge University Press, pp. 361-40
  8. ↑ 8.0 8.1 EEA, 2014. National adaptation policy processes in European countries — 2014. EEA report 2014/4
  9. ↑ 9.0 9.1 Sayers, P., Li, Y. Galloway, G., Penning-Rowsell, E., Shen, F., Wen, K., Chen, Y., and LeQuesne, T. 2013. Flood Risk Management: A Strategic Approach. Paris, UNESCO
  10. ↑ Pappenberger, F., Harvey, H., Beven, K., Hall, J., Romanowicz, R. and Smith, P. 2006. Implementation Plan for library of tools for uncertainty evaluation. Report provided as part of the UK Flood Risk Management Research Consortium https://www.academia.edu/22878506/Implementation_Plan_for_Library_of_Tools_for_Uncertainty_Evaluation
  11. ↑ Jonkman, S.N. and Vrijling, J.K. 2008. Loss of life due to floods. Flood Risk Management 1: 43–56
  12. ↑ Marchau, V.A.W.J., Walker, W.E., Bloemen, P.J.T.M., Popper, S.W. (Eds.) 2019. Decision Making under Deep Uncertainty. From Theory to Practice. Springer
  13. ↑ Rumsfeld, D. 2002. Defense.gov News Transcript: DoD News Briefing – Secretary Rumsfeld and Gen. Myers. United States Department of Defense. February 12, 2002
  14. ↑ IPCC, 2014. Climate Change 2014: Synthesis Report. Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Core Writing Team, R.K. Pachauri and L.A. Meyer (eds.)]. IPCC, Geneva, Switzerland, 151 pp.
  15. ↑ Gallopin, G.C. and Raskin, P. 1998. Windows on the Future: Global Scenarios and Sustainability. Environment 40: 6-31
  16. ↑ 16.0 16.1 Haasnoot, M., Kwakkel, J.H., Walker, W.E. and Ter Maat, J. 2013. Dynamic adaptive policy pathways: A method for crafting robust decisions for a deeply uncertain world. Global Environmental Change 23: 485–498
  17. ↑ Kwadijk, J. C. J., Haasnoot, M., Mulder, J. P. M., Hoogvliet, M., Jeuken, A., van der Krogt, R., van Oostrom, N.C.G., Schelfhout, H.A., van Velzen, E.H., van Waveren, H. and de Wit, M.J.M. 2010. Using adaptation tipping points to prepare for climate change and sea level rise: A case study in the Netherlands. Wiley Interdisciplinary Review Climate Change, 1(5): 729–740
  18. ↑ Haasnoot, M., Middelkoop, H., Offermans, A., van Beek, E., van Deursen, W.P.A. 2012. Exploring pathways for sustainable water management in river deltas in a changing environment. Clim. Change 115: 795-819
  19. ↑ McGahey, C. and Sayers, P.B. 2008. Long term planning – robust strategic decision making in the face of gross uncertainty – tools and application to the Thames. In: Flood Risk Management: Research and Practice. Proceedings of FLOODrisk 2008, Taylor & Francis, London, UK, pp. 1543–1553
  20. ↑ 20.0 20.1 Lawrence, J., Boston, J., Bell, R., Olufson, S., Kool, R., Hardcastle, M. and Stroombergen, A. 2020. Implementing Pre-Emptive Managed Retreat: Constraints and Novel Insights. Current Climate Change Reports 6: 66–80
  21. ↑ IPCC, 2011. Summary for Policymakers. In: Intergovernmental Panel on Climate Change Special Report on Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation. Authors: Field, C. B., Barros, V., Stocker, T.F., Qin, D., Dokken, D., Ebi, K.L., Mastrandrea, M.D., Mach, K.J., Plattner, G.-K., Allen, S.K., Tignor, M. and Midgley, P.M. (eds.). Cambridge University Press
  22. ↑ Breton, F. 2006. Report on the use of the ICZM indicators from the WG-ID. A contribution to the ICZM evaluation. EEA, European Topic Centre Terrestrial Environment, Universitat Antònoma de Barcelona
  23. ↑ Martí, X., Lescrauwaet, A-K., Borg, M. and Valls, M. 2007. Indicators Guidelines To adopt an indicators-based approach to evaluate coastal sustainable development. Deduce project, Department of the Environment and Housing, Government of Catalonia. http://www.im.gda.pl/images/ksiazki/2007_indicators_guidelines.pdf


The main author of this article is Job Dronkers
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