Climate adaptation policies for the coastal zone

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In this paper policy strategies are discussed for tackling the challenges of climate adaptation for the coastal zone. It should be read in conjunction with the Coastal Wiki article Integrated Coastal Zone Management (ICZM). Parts of this page 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 for many coastal zones [2] (see also the article Sea level rise). Many coastal zones around the world are already lying around or even below high-water sea levels, especially coastal delta plains and small islands. The wave climate is also expected to become more extreme in various regions of the world, in particular in coastal areas south of the equator, but also in coastal areas around the North Sea and the Baltic Sea (Mentaschi etal., 2015[3]; Metel et al., 2018[4]). Soil subsidence, saline intrusion and water shortage add to the vulnerability (Deltares, 2105)[5], which is further exacerbated by fast population growth (Barragan et al., 2015[6]). 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.

Uncertainty and awareness

Countries with low-lying coastal zones will have to face climate change and some impacts are already occurring. However, separating the impacts of climate change from change produced by other natural or human causes is still very difficult. Uncertainty about the impacts of climate change is a serious (perhaps the most serious) obstacle to raising public awareness and for getting climate adaptation high on the political agenda, compared to issues with a more immediate impact [8]. Uncertainty about the possible impact of climate change is not the only reason. The fact that the greatest impacts are related to exceptional extreme events also plays a role. According to a survey among European policymakers, the occurrence of an extreme weather event is presently the most important trigger for progress in climate adaptation [8].

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. The assessment of risk, defined as the product of probability of occurrence and resulting damage, theoretically provides an objective measure for the need to adapt to these impacts. 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], for instance, by using a Monte Carlo method (Pappenberger et al., 2006 [10]; assumptions have to be made for the probability distributions of independent variables involved in the risk assessment). The application of the risk concept in adaptation strategies is limited, however, by the difficulty to quantify uncertainty in the probability of occurrence and by the more fundamental difficulty to assess 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].


It is very likely that sea level rise will go on for a long time [13]. The same holds for other developments, for example developments related to population growth. Planning for climate change adaptation therefore requires a long-term prospect, taking into account different scenarios for the future. 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 [14]. 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, which are in general major shortcomings of current coastal adaptation strategies. However, scenarios do not answer the question which adaptation strategy among different options should be preferred.

Adaptation pathways

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 questions 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 and economic developments. A static plan is inadequate, as the future can unfold differently from what is anticipated. Actions that are appropriate for the foreseeable future can reveal inadequate for the long term and even hinder actions that may become necessary later.

One way to deal with this problem of “robust decision making” is the strategy of adaptive pathways (Haasnoot et al., 2012[15]). According to this strategy, adaptation pathways are developed that consist of different sets of successive adaptation actions. Each step of such a pathway should ultimately lead to successful long term adaptation within a particular scenario of climate change and socio-economic development. The analysis of the different pathways enables the selection of short term actions that are suitable (no adverse lock-in effects) within different scenarios. 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 and socio-economic 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) [17]. For an effective implementation of the adaptive pathways strategy, it is essential that any development project in the coastal zone that has a potential impact on future adaptation is evaluated against this strategy.

Low-regret adaptation strategy

Figure 1. An artificial dune protects the seafront of Noordwijk coastal village (Netherlands).
Figure 2. A massive foreshore nourishment increases the strength of the narrow dune system protecting the coast between Rotterdam and The Hague (Netherlands). The sand nourishment, which also serves recreational purposes, will spread over time along the coast and feed the dune belt.

A reasonable and generally preferred strategy for climate change adaptation is to start with so-called 'low-regret measures' or, even better, 'no-regret measures' (Hallegatte, 2009 [18]). These are adaptation measures that generate immediate benefits without the need for high additional investments. Examples of such measures are:

  • Choose building with nature solutions for renewing coastal infrastructural works when they have reached the end of their life span (e.g., wetland restoration, dune/beach/shoreface nourishments);
  • Adjust design criteria to extend the lifetime of infrastructural works by incorporating the expected sea level rise in the periodic maintenance/renovation scheme;
  • Make spatial reservations for nature development (or for other temporal benefits) which can eventually serve later for future reinforcement or realignment of coastal defenses;
  • Introduce setback lines to gradually replace settlements in future high-risk areas with nature development with a protective function (e.g., stimulating dune growth, mangrove development).
Figure 3. Mangrove reforestation project in Chachoengsao district, Thailand.

Other no-regrets measures include early warning systems; risk communication between decision makers and local citizens; sustainable land management, including land use planning; ecosystem management and restoration; improvements to water supply, sanitation, irrigation and drainage systems; development and enforcement of building codes (considering also geotechnical aspects) and better education and awareness [19]. Such measures deliver additional benefits, such as opportunities for tourism, recreation, nature development and other ecosystem services.

No-regret (or low-regret) measures are implemented step by step, allowing for adjustment when better knowledge of the impacts of climate change impacts becomes available. They are preferably designed according to the insight that natural dynamics generally offer greater long-term resilience (self-regulating capacity) against climate change impacts than hard man-made structures. A few examples of no-regret / low-regret adaptation measures are illustrated in figures 1-6.

Figure 4. Realignment of coastal defences and wetland restoration projects in the Humber estuary (UK).
Figure 5. Vegetated foreshores reduce the wave impact on coastal defense structures[20]. Dikes along the Dutch Wadden Sea coast are protected by salt marshes created by natural sedimentation stimulated by rows of braided willow twigs.

Figure 6. Climate adjustment of sea defenses and river dikes in the Netherlands: The design conditions for sea defenses and river dikes are evaluated every 12 years and adapted to the latest insights regarding extreme climate conditions. Unsafe defenses are then reinforced. The old 6 km long sea dike along the North Holland coast has been reinforced with an artificial fronting dune.

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). A broad range of measures in different sectors that are listed in this article (Table 4: Actions for the implementation of Integrated Coastal Zone Management) can contribute to climate adaptation. Another overview of relevant measures has been drawn up by USAID (2009) [21], see Table 1.

Table 1. Climate adaptation measures for the coastal zone [21]

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 [19]. Such an iterative risk management strategy consists of an iterative 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 a better understanding of climate change impacts in the coastal and marine zone. A coordinated and consistent approach to marine and marine monitoring is essential for a proper analysis of change in the coastal and marine system. This analysis should focus on the establishment of cause-impact relationships, which make it possible to distinguish climate change impacts from natural variability and other impacts. Monitoring data are often not directly fit 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). Measurable indicators and quantitative targets are essential to assess progress in climate adaptation, to inform policy and the general public and to develop adaptive capacities of institutions and the wider society.

Financing climate adaptation

In many developing countries the impact of climate change is exacerbated by fast urban development in the coastal zone, especially in Asia and Africa (Neumann et al.; 2015[24]). However, financial claims for coastal zone climate adaptation have to compete with other urgent development priorities. Grants and loans from international donor programs are an important resource for many developing countries. Several donor programs provide opportunities for financing coastal zone climate adaptation. An overview of these programs is given in 'A Resource Guide to Climate Finance' (2018)[25]. A few important international funding programs are specifically mentioned below.

The Adaptation fund

The Adaptation Fund ( was established to finance concrete adaptation projects and programs in developing countries that are parties to the Kyoto Protocol and are particularly vulnerable to the adverse effects of climate change. Since 2010, the Adaptation Fund has committed US$ 532 million, including supporting 80 concrete adaptation projects with about 5.8 million direct beneficiaries.

The Global Environmental Facility (GEF)

Funds of the Global Environmental Facility ( are available to developing countries and countries with economies in transition to meet the objectives of the international environmental conventions and agreements. GEF support is provided to government agencies, civil society organizations, private sector companies, research institutions, to implement projects and programs in recipient countries. The Global Environment Facility (GEF) was established at the 1992 Rio Earth Summit to tackle environmental problems; the World Bank serves as the GEF trustee, administering the GEF Trust Fund. Since 1992, the GEF has provided US$ 17 billion in grants and has mobilized an additional US$ 88 billion in loans for 4000 projects in 170 countries.

The Green Climate Fund (GCF)

The Green Climate Fund ( is a financial mechanism under the UNFCCC, established at COP16 in 2010, adopted in 2011, and operational since 2015. The Fund is a global platform to respond to climate change by investing in low-emission and climate-resilient development. The GCF was established to limit or reduce greenhouse gas (GHG) emissions in developing countries, and to help vulnerable societies adapt to the unavoidable impacts of climate change. In 2018 the committed funding was 4.6 billion US$.

Related articles

Integrated Coastal Zone Management (ICZM)
Sea level rise
Setback area

Further reading

CoastAdapt website


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The main author of this article is Job Dronkers
Please note that others may also have edited the contents of this article.

Citation: Job Dronkers (2019): Climate adaptation policies for the coastal zone. Available from [accessed on 3-08-2021]