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"Adaptation options for coastal management are most effective when incorporated with policies in other areas, such as disaster mitigation and land-use plans."(49)
The physical impacts of climate change on the coastal zone will vary by location and depend on a range of biophysical and socio-economic factors, including human response.(50) Appropriate adaptation will play a pivotal role in reducing the magnitude and extent of potential impacts, thereby decreasing the vulnerability of the coastal zone to climate change. In many cases, existing techniques and technologies used to deal with past water level changes could also serve as effective adaptations for future climate change.
To date, relatively little attention has been given to understanding the motivations for adaptation, and the barriers that may exist to successful adaptation. Rather, most of the adaptation literature examines methods used to address changes in water levels. Over recent years, three trends have been observed in coastal adaptation and associated technology use:
- increase in soft protection (e.g., beach nourishment and wetland restoration), retreat and accommodation;
- reliance on technology, such as geographic information systems, to manage information; and
- awareness of the need for coastal adaptation that is appropriate for local conditions.(51)
Strategies for Dealing with Sea Level Rise
Many believe that, on a global scale, the consequences of sea level rise could be disastrous if appropriate adaptation measures are not taken.(49) The following discussion focuses on the three basic strategies of protect, accommodate and retreat,(3) and the range of technological options available for each.
Protecting the coastline through mechanisms such as seawalls and groins has been the traditional approach to dealing with sea level rise in many parts of the world. The goal of protection is generally to allow existing land use activities to continue despite rising water levels.(3) Such measures range from large-scale public projects to small-scale efforts by individual property owners. Traditional protection measures tend to be expensive and may have limited long-term effectiveness in highly vulnerable locations.(19)
Consequently, there has been growing recognition during the last few years of the benefits of 'soft' protection measures, including beach nourishment and wetland restoration and creation.(51) These measures can be implemented as sea level rises, and are therefore more flexible than, for example, seawalls, the expansion of which may require the removal or addition of structures. It should be noted, however, that the transition from hard to soft protection requires knowledge and understanding of physical coastal processes in the region.(3) Soft protection can enhance the natural resilience of the coastal zone and is generally less expensive than hard protection, which can lead to unwanted effects on erosion and sedimentation patterns if not properly implemented.(51)
Accommodation involves continued occupation of coastal land while adjustments are made to human activities and/or infrastructure to accommodate sea level changes, and thereby reduce the overall severity of the impact.(3) Accommodation strategies may include redesigning existing structures, implementing legislation to encourage appropriate land use and development, such as rolling easements, and enhancing natural resilience through coastal dune and wetland rehabilitation. Examples include elevating buildings on piles, shifting agriculture production to salt-tolerant crops,(3) controlling and/or prohibiting removal of beach sediment,(19) and developing warning systems for extreme high sea level events, flooding and erosion.(36)
Retreat involves avoiding risk in order to eliminate a direct impact.(3) With this strategy, no attempts are made to protect the land from the sea. Instead, land that is threatened by sea level rise is either abandoned when conditions become intolerable, or not developed in the first place. For example, legislated setback regulations may be used to reduce future losses from erosion.(19) In some cases, resettlement may be a cost-effective long-term alternative to coastal protection works.(19)
Researchers recommend that adaptation to climate change in the coastal zone be considered as a component of a larger, integrated management framework, as promoted in Canada's Oceans Act. This would help to manage the complexity of the adaptation process, and encourage researchers, policy-makers and stakeholders to work together.(52) Stakeholders must be involved from the beginning of the process and actively engaged in discussions of potential adaptive measures.(53)
To assess the vulnerability of a region or community, it is necessary to consider both the magnitude of the potential impacts as well as our capacity to adapt to those impacts. An important factor of such analysis is the rate at which change is expected to occur. For example, a gradual rise in sea level may allow most coastal infrastructure to be adapted during the course of normal maintenance or replacement, making accommodation or retreat viable options. In contrast, a more rapid rate could necessitate expensive protective measures or replacement in less than the design lifespan of the facility. Assessment often involves conducting specific case studies in the region of concern (see Box 5). The following sections discuss specific regional examples of adaptation to climate change. While these include suggestions for adaptation options, detailed examinations of the processes of adaptation and the viability of potential adaptation options have, in most cases, not been conducted.
BOX 5: Assessing coastal community vulnerability(54)
Consulting with community residents to identify impacts of local concern was the critical first step of this study in Conception Bay South, Newfoundland. These concerns included coastal erosion, infrastructure damage and implications for town management and development. Researchers then used historic data to evaluate past climatic impacts and to identify which parts of the coast are most sensitive to flooding and erosion. Finally, options (preventing development in areas of known vulnerability, implementing setback limits) were recommended as a proactive means of limiting future impacts.
Topsail Beach, Conception Bay South, Newfoundland. Photo courtesy of Norm Catto.
Prince Edward Island
In Prince Edward Island, potential adaptation strategies that have been identified and discussed in the literature include identification and monitoring of hazards (e.g., flood mapping), managed retreat or avoidance (e.g., restricted development in sensitive areas), accommodation, and enhanced awareness-raising and public education.(19) The most appropriate adaptation measures will depend on the conditions at the specific site of concern. For example, retreat is likely not a viable option in urban settings such as Charlottetown. In these areas, strategies that incorporate elements of accommodation and protection would have to be considered, with both hard and soft protection likely necessary to protect valuable coastal infrastructure.(19)
On Prince Edward Island's north shore, a complex system of sand dunes is a major tourist attraction that is at risk of being breached by storm-induced wave activity. These dunes serve as a natural barrier that protects the shoreline from ongoing coastal processes, the absence of which could lead to accelerated erosion in sensitive areas.(19) Adaptation strategies along the north shore could include accommodating rising sea levels by enhancing natural resilience through dune rehabilitation, and soft protection such as beach nourishment and sand storage.(19) Overall, a range of adaptation strategies would be needed in Prince Edward Island, and would be most successful if several options were to be considered, at various scales, in deliberations that include stakeholder participation.(19)
Structures are already used in the Fraser Delta to protect the land from the sea. However, if extreme flooding and storm-surge events were to occur more frequently as a result of future climate change, there would be an increased risk of breaching and additional damage to dyke systems.(37) Yin(37) recommended several adaptation options for the Fraser Delta coastal zone, based on the potential impacts of climate change on this region. These options include
- prevention of further development in sensitive areas;
- ensuring that new development does not infringe upon the shoreline;
- public repurchase of sensitive land and infrastructure; and
- protecting existing investments by maintaining, extending and upgrading existing dyke systems to prevent damage to coastal infrastructure and human activities.
Individual property owners along the shores of the Great Lakes would be impacted if projected decreases in lake levels were to occur, although they will likely be able to adapt, in most cases, by moving with the lake (e.g., extending docks; references 11, 45). Shoreline protection structures designed for the current range of lake levels would also be affected by water level changes. As a result, the design and implementation of flexible structures that can be modified for a range of water levels could represent an appropriate form of anticipatory adaptation.(45, 55) Decisions will also have to be made regarding coastal land use and development. For example, existing shoreline management policies and plans may need to be adjusted and new policies that limit pressure for lakeward development of sensitive areas of the shoreline could be used to help reduce potential impacts from coastal hazards.(11, 56)
Dredging is a commonly recommended adaptation option for dealing with low water levels in the Great Lakes. In 2000, Fisheries and Oceans Canada initiated the Great Lakes Water Level Emergency Response Program, to provide $15 million in dredging assistance to marinas severely affected by low water levels.(57) However, from an economic and environmental perspective, dredging is not always a feasible option. For example, the Welland Canal is situated on a rock basin, and deepening this structure would require a multiyear drilling and blasting project.(58) A study investigating harbour dredging in a portion of the Great Lakes concluded that costs at Goderich, Ontario might be as high as $6.84 million for one future water level projection.(59) Furthermore, in contaminated areas, extensive dredging could lead to high disposal costs and present a public health and environmental hazard to shoreline interests and activities.(43)
Changes to regulation of the Great Lakes have also been suggested as a potential adaptation option. Regulation of Lake Ontario and the St. Lawrence River is currently being studied to evaluate the benefits and impacts of the current plan used to regulate these water bodies, and assess the changes that would be needed in order to meet current and future needs, including those under climate change scenarios.(60) With respect to increasing regulation to include all five Great Lakes, research has found that this option is neither economically nor environmentally feasible at the present time.(61)