To prevent the water from inundating  coastal cities, the dominant coastal protection model[124] for many Danish coastal cities has been to implement human-made engineered structures that attempt to keep nonhuman forces (such as water) at bay (Faragò et al., 2018). This approach is often referred to as the “hard approach” (ibid.). It consists of seawalls, dikes, locks and levees, which are engineered infrastructures working as defence systems to manage and contain the water. These systems are designed to cater to rising sea levels and the increasing threat of storm surges.

     While these infrastructures have an important role in protecting low-lying coastal cities in the immediate short term, due to future sea-level rise being somewhat unpredictable, it is difficult to design defence systems, such as sea walls, based on uncertainty (Pilkey and Young, 2011). Moreover, past disasters around the world have shown that reliance on hard approaches can be catastrophic, especially in the event of structural failure of hard approaches. Furthermore, levees (i.e. sea walls, dikes) are constructed based on a maximum height that can protect the city up to a certain flood level. However, there is no guarantee that the flood will not surpass the protection capacity or penetrate below the sea wall via groundwater. For instance, Hurricane Katrina in New Orleans overtopped the seawalls and broke through the coastal barrier. In that case, the seawall prevented the water that had toppled the wall into the city from flushing out back to sea, causing a pond-like effect, and causing huge damages (UC Berkeley News, 2005; Pilkey and Young, 2011). Furthermore, these engineered solutions are very expensive and inflexible to refurbish. Therefore, without undermining the importance of technological solutions, they are temporary solutions with limitations in engaging with the complex phenomenon of climate change (Pilkey and Young, 2011).

     Moreover, a heavy reliance on protection/barrier systems such as dikes and sea walls can be said to rest on a false sense of security, as they are not sufficiently designed to be adaptable to future changes in climate. This phenomenon is called the “levee paradox”,[125] which describes the irony of the presence of levees that leads to less awareness of the flooding risks and, in turn, increased development in the so-called “protected” risk area (Smith, 2002). Thus, their very existence and presence encourage an increase in the density of development, making long-term response all the more difficult and expensive (Pilkey and Young, 2011).

    While allocating resources around unforeseeable future risks is difficult, it is even more difficult to imagine better practices without first uncovering the limitations in the existing infrastructural systems (Orff, 2016).  Thus, coastal cities’ challenges with water will require going beyond implementing coastal protection strategies, as these approaches do not address the actual source of these issues.  

Barriers to retreat

An underlying but crucial problem with the defence strategies of the hard approach is not only that they cannot guarantee 100% protection, but they rarely suggest relocating people away from high-risk areas (Pilkey, Pilkey-Jarvis and Pilkey, 2016). There is an inertia in Denmark to retreat from the most vulnerable areas of coastal cities. For instance, there is currently no national comprehensive retreat plan of risk areas or designating risk areas as “no build areas” [126] in urban areas for the future. The current political and economic climate[127] is geared towards development[128] over retreat. For this reason, it is not surprising that managed retreat (also known as realignment or relocation) as a coastal adaptation strategy is the least discussed option when deciding how to respond to the water issues for coastal cities in Denmark[129] and around the world (Pilkey, Pilkey-Jarvis and Pilkey, 2016; Siders, 2019). Prolonging a sensible retreat plan for critical areas can make future responses to sea-level rise and storm surges more difficult and expensive in the future (Pilkey and Young, 2011). Nevertheless, retreat is a difficult issue to discuss and implement for different factors that can act as barriers that reinforce each other (i.e. psychological, perceptual, regulatory, institutional, practical and physical barriers) (Siders, 2019). Research by Rupp-Armstrong and Nicholls (forthcoming[130]) investigated some of the main barriers to implementing managed retreat in England, Scotland, the Netherlands and Germany. Moreover, Siders (2019) and Pilkey et al. (2016) investigated cases in the United States. Here are some of the findings that are barriers to retreat (not an exhaustive list) that may also apply to the Danish context:

• The lack of public acceptance is due to the negative perception of loss of land and real estate value in risk areas (Leggett, Harvey and Cooper, 2004; Rupp-Armstrong and Nicholls, forthcoming).

• Not being able to get proper or decent compensation for their loss of land and not being satisfied with the proposed solutions (Rupp-Armstrong and Nicholls, forthcoming; Siders, 2019).

• High costs associated with retreating existing urban infrastructure due to its size, inflexibility and complexity behind legal liabilities due to different coastal land owners over the area (buy back costs) (Rupp-Armstrong and Nicholls, forthcoming; Siders, 2019).

• The lack of available land to safely relocate to (i.e. this is particularly the case for the Netherlands, where they have high population density and lack of suitable land to safely relocate to) (Rupp-Armstrong and Nicholls, forthcoming; Siders, 2019).

• Overestimating the capacity of techno-centric engineering solutions with a view that one can always engineer oneself out of these issues (Pilkey and Young, 2011; Pilkey, Pilkey-Jarvis and Pilkey, 2016). This belief is often termed “optimism bias”, which refers to the tendency of people to believe nothing bad will happen to them (Siders, 2019).

• An existing community with a strong place attachment (i.e. historical, cultural and/or psychological factors) to the coastal area and livelihoods depend on the risk area. Moreover, people that want to maintain the status quo and resist action due to “status quo bias” (Siders, 2019).

• A lack of collective “flood memory”, short-term thinking and/or the lack of perception and awareness of threat (Siders, 2019).

• Actors (i.e. residents, local and state governments, real estate industry) who hold power to make decisions on managed retreat have financial incentives to prevent retreat plans from being implemented. At the same time, stakeholders with an incentive to support retreat (i.e. federal taxpayers, federal agencies and future generations) have little to no power. This is particularly the case in the USA (Siders, 2019, p.218).

• Property developers are encouraged to build on risk areas like the coast to make short-term profits but are free from the long-term consequences of their development. (Siders, 2019, p.219).

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