Coastal zones are extremely vulnerable to the effects of global climate change and accelerated sea-level rise. Coastal areas that are exposed to human impacts and natural changes are at increased risk of shoreline retreat and land loss, which can lead to increased hazard potential for coastal populations, infrastructure, and investment (Klein & Nicholls, 1998). Over the past 100 years, global sea-level has risen by 1.0-2.5 mm yr-1 (Klein & Nicholls, 1999) and it has been estimated that by 2100 there will be an increase in sea-level of between 15 and 95 centimetres (USGS, 2000), with a best estimate of 50cm (IPCC, 2005). Predicting future impacts to coastal zones is a difficult task, as there are a number of variables that influence coastal evolution, such as socio-economic impacts and natural changes. Over the past twenty years there has been an increased effort in developing guidelines and methodologies to assess coastal vulnerability (Klein & Nicholls, 1999). In 1992, the former Coastal Zone Management Subgroup of the Intergovernmental Panel on Climate Change (IPCC) published its Common Methodology for Assessing the Vulnerability of Coastal Areas to Sea-Level Rise (IPCC CZMS, 1992). In 1994 the IPCC developed Technical Guidelines for Assessing Climate Change Impacts and Adaptations (Carter et al., 1994) and the United Nations Environment Program (UNEP) used the IPCC Technical Guidelines to develop the Handbook on Methods for Climate Change Impact Assessment and Adaptation Strategies (Klein et al., 1998), which contains an entire chapter on coastal zones. A fourth methodology, Coastal Vulnerability Index (CVI) was developed by Gornitz et al. (1994) and was later modified by Hammar-Klose & Thieler (2001). Each of these publications provide generic frameworks, which were designed to assess the potential consequences of climate change in any natural or socio-economic system and to identify options to respond to the effects (Klein & Nicholls, 1999). This report will focus on the IPCC Technical Guidelines, CVI, and the IPCC Common Methodology, which has been the most widely used methodology to assess coastal vulnerability, and their application to the assessment of Nova Scotia’s coastal zones, specifically the issue of sea-level rise and its effects on coastal development.
According to Klein and Nicholls (1999) “vulnerability of coastal zones has been defined as the degree of incapability to cope with the consequences of climate change and accelerated sea-level rise” (p. 183). Based on this definition coastal vulnerability assessments must include the assessment of anticipated impacts, as well as the assessment of available adaptation options (Klein & Nicholls, 1999). Vulnerability assessment processes can be structured into three levels of increasingly complex assessment: screening assessment (SA); vulnerability assessment (VA); and planning assessment (PA) (CPACC, 1999). SA is a screening process, which uses existing data and the judgement of local experts and focuses on susceptibility (CPACC, 1999 and Klein & Nicholls, 1999). VA is a more comprehensive analysis and includes socio-economic changes and other climate change, and requires a previous SA or VA (CPACC, 1999 and Klein & Nicholls, 1999). PA requires a high level of detail, includes socio-economic, climatic changes, as well as non-climate changes, and would take place in the wider context of coastal management (CPACC, 1999 and Klein & Nicholls, 1999). The IPCC Common Methodology consists of seven main steps of analysis, which take into account the assessment of both the impacts as well as the possible responses to the impacts. The Common Methodology framework “incorporates expert judgement and data analysis of socio-economic and physical characteristics to assist the user in estimating a broad spectrum of impacts from sea-level rise, including the value of lost land and wetlands” (IPCC Common Methodology, 1991). The seven steps of the frame work include: (1) delineate the case-study area; (2) inventory study area characteristics; (3) identify the relevant socio-economic development factors; (4) asses the physical changes; (5) formulate response strategies; (6) assess the Vulnerability Profile; and (7) identify future needs. These steps are suggestions of analysis that should be done; however, with the Common Methodology there are no specific instructions on how the analysis should be performed, which is meant to encourage users to apply the framework appropriately to their specific situation. The key output of the Common Methodology includes the vulnerability profile for the specified case-study area and a list of future policy needs to adapt both physically and economically (IPCC Common Methodology, 1991). The IPCC’s Technical Guidelines were developed to serve as a more generic framework for any natural or socio-economic system, unlike the Common Methodology, which was developed specifically for coastal zones (Klein & Nicholls, 1999). The Technical Guidelines consist of seven steps, which are very similar to the Common Methodology: (1) define the problem; (2) select method; (3) test method/sensitivity; (4) select scenarios; (5) assess impacts; (6) assess autonomous adjustments; and (7) evaluate adaptation strategies. As stated in the objectives of the Technical Guidelines “the ultimate purpose of the Guidelines is to enable estimations of impacts and adaptations which will allow comparable assessments to be made for different regions/geographical areas, sectors and countries” (pg. v). Three coastal adaptation strategies have been identified when discussing sea-level rise: protect (defend vulnerable areas, especially population centres, economic activities, and natural resources), accommodate (strike a balance between preservation and development), and retreat (abandon structures in developed areas and ensure that new developments are set back from the shore) (Shaw et al., 1998).
Shaw et al. (1998) published a report titled Potential Impacts of Global Sea-Level Rise on Canadian Coasts, which concluded that 3% of the total Canadian coastline was at high sensitivity to sea-level rise, with sensitivity being defined as the likelihood that physical changes due to sea-level change will occur at the coast. To assess the sensitivity of the Canadian coastline Shaw et al. used a method that combined data on seven variables: relief, rock type, coastal landform, sea-level tendency, shoreline displacement rate, mean tidal range, and mean annual maximum significant wave height, and assigned each variable a risk value in the range of 1 to 5. Through the use of the methodology it was discovered that the Maritime region makes up a large portion of the high sensitivity coastal area. These areas of high sensitivity will likely be subjected to a series of opposed effects with sea-level rise, including: more frequent overwashing of beaches and higher rates of beach retreat and in other areas the formation of new beaches will take place (Shaw et al., 1998). Rates of unconsolidated cliff erosion could increase, but erosion would be interspersed with intervals of stability and small parts of the Atlantic coast of Canada would be permanently submerged (Shaw et al., 1998).
To deal with the impending sea-level rise in Nova Scotia, in 2009 the provincial government developed The State of Nova Scotia’s Coast Report, which provides an overview of the condition of the coastal areas and resources and has the ultimate goal of ensuring the sustainable development and conservation of the coastal areas and resources of Nova Scotia. The report identifies six priority coastal issues in the province: coastal development, working waterfronts, public coastal access, sea-level rise and storm events, coastal water quality, and sensitive coastal ecosystems and habitats.
In Atlantic Canada sea-level rise is occurring due to a number of factors, including: general rise in average sea-level, regional subsidence, and global warming associated with climate change (Nova Scotia’s Coast Report, 2009). Some of the greatest areas at risk of sea-level rise in Nova Scotia are low lying areas, areas with frequent storm conditions and high storm-surge potential, areas with coastal infrastructure and property, areas of sensitive ecology, and areas of rapid coastal erosion (Nova Scotia’s Coast Report, 2009). Sea-level rise occurring on the coast of Nova Scotia will have large effects on human development taking place along the coastlines. According to Nova Scotia’s Coast Report “coastal development is defined as the human-induced alteration of the landscape, including the erection of structures, within sight of the coastline” (p. 91). High sensitivity exists around residential development along the coast of Nova Scotia, with 11 percent of the coastline being intensely developed urban and industrial areas (Nova Scotia’s Coast Report, 2009). According to the Nova Scotia’s Coast Report “the most densely developed coastal areas are associated with ports and harbours”, which exist in areas such as Halifax, Antigonish, and Yarmouth. The assessment of sea-level rise and its effects on coastal development in the province could be done through the use of the Coastal Vulnerability Index (CVI) in combination with the Common Methodology. Using the Coastal Vulnerability Index (CVI) methodology allows for the assessment of various factors and their relative contributions and interactions. Hammar-Klose and Thierler’s (2001) CVI looks at six variables: tidal range, wave height, coastal slope, shoreline erosion rates, geomorphology and historical rates of relative sea-level rise. Scientists using CVI apply a mathematical formula (CVI = ((a*b*c*d*e*f)/6)1/2 ) to relate the different types of data to each other to calculate an index value. “The index allows the six physical variables to be related in a quantifiable manner that expresses the relative vulnerability of the coast to physical changes due to sea-level rise. This method yields numerical data that cannot be equated directly with particular physical effects. It does, however, highlight those regions where the various effects of sea-level rise may be the greatest” (Hammar-Klose & Thierler, 2001). Each physical variable evaluates specific physical effects that occur on the coast in response to sea-level rise and each variable is calculated in a unique way. The geomorphology variable indicates the relative erodibility of different sections of shoreline and is ranked qualitatively according to the relative resistance of the coastal landforms and rocks to marine erosion. Data concerning geomophology is collected through detailed maps (geological, topographic, and geomorphological) and is used in combination with descriptive information (Hammar-Klose & Thieler, 2000). The regional coastal slope (steepness or flatness of the coastal region) evaluates both the relative risk of inundation and the potential rapidity of shoreline retreat and can be calculated through the use of a Digital Elevation Model that is created from topographic diagrams (Hammar-Klose & Thieler, 2000 & Gaki-Papanastassiou et al., n.d.). The relative sea-level change variable corresponds to the increase or decrease in mean water elevation over time as measured at tide gauge stations and the data is usually collected from historical records, and therefore only show change for recent time scales (Hammar-Klose & Thieler, 2000 & Gaki-Papanastassiou et al., n.d.). Shoreline erosion rates evaluate how fast a section of shoreline has been eroding, the data can be collected from a variety of sources including published reports, historical shoreline change maps, field surveys and aerial and satellite photo analyses (Hammar-Klose & Thieler, 2000 & Gaki-Papanastassiou et al., n.d.). Mean tide is linked with inundation hazards and the data is usually collected from published information (Hammar-Klose & Thieler, 2000 & Gaki-Papanastassiou et al., n.d.). The final variable is wave height, which is also linked to inundation and the data can be collected from published information in addition to the use of a sea-level tidal gauge (Hammar-Klose & Thieler, 2000 & Gaki-Papanastassiou et al., n.d.). Using the collected information and data, maps could be created and used to provide insight into the relative potential of coastal change due to future sea-level rise.
The information concerning Nova Scotia’s coasts provided through the CVI could be used in conjunction with the Common Methodology to reveal the physical and socio-economic impacts of sea-level rise and to assist with furthering physical and economic modeling. As previously mentioned 11 percent of Nova Scotia’s coast line is intensely developed with urban and industrial areas and roughly 70 per cent of the province’s population lives in coastal communities (Nova Scotia’s Coast Report, 2009). Applying the Common Methodology will “allow for the identification of populations and resources at risk, and the costs and feasibility of possible responses to adverse impacts” (Klein & Nicholls, 1999). It will also provide information regarding elements of the natural coastal system, such as beaches cliffs, estuaries and tidal rivers, freshwater marshes, salt marshes, small islands, aquifers and species and ecosystems. It will also highlight the socio-economic impacts of sea-level rise such as direct loss of economic, ecological, cultural and subsistence values through loss of land, infrastructure and coastal habitats; increased flood risk of people, land and infrastructure; and impacts related to changes in water management, salinity and biological activity (Klein & Nicholls, 1999). These findings will assist in the development and application of long term coastal management plans.
Climate change and rising sea-levels will have a large effect on many coastal zones in the near future. Coastal Vulnerability Assessments can assist with predicting future coastal evolution and the impacts that may occur due to sea-level rise. Coastal Vulnerability Assessments also allow scientists and researchers to examine a number of coastal variables that are affected by climate change and relate them to one another to provide the most effective adaptation strategies. The information that is provided through the assessments can be used to help identify the risks for natural systems, government systems, as well as socio-economic and cultural systems as well as in the development of national, provincial, or municipal coastal management plans.
References
Caribbean Planning for Adaptation to Global Climate Change (CPACC) Project (1999). Coastal Vulnerability Assessment for Sea-Level Rise: Evaluation and Selection Methodologies for Implementation. Retrieved from http://fama2.us.es:8080/turismo/turismonet1/economia %20del%20turismo/turismo%20de%20costas/COASTAL%20VULNERABILITY%20LEVEL%20SEA.PDF
Carter, T., Parry, M., Nishioka, S., & Harasawa, H. (1994). IPCC Technical guidelines
for assessing climate change impacts and adaptations. Retrieved from http://www.ipcc.ch/pdf/special-reports/ipcc-technical-guidelines-1994n.pdf
Gaki-Papanastassiou, K., Karymbalis, E., Poulos, S., Seni, A. & Zouva, C. (n.d.). Coastal vulnerability assessment to sea-level rise bαsed on geomorphological and oceanographical parameters: the case ofArgolikos Gulf, Peloponnese, Greece. Retrieved from http://hua.academia.edu/EfthimiosKarymbalis/Papers/398105/Coastal_ vulnerability_assessment_to_sea-level_rise_based_on_geomorphological _and_oceanographical_parameters_the_case_of_Argolikos_Gulf_Peloponnese_Greece
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Government of Nova Scotia. (2009). The 2009 state of Nova Scotia’s coast technical report. Retrieved from http://www.gov.ns.ca/coast/state-of-the-coast.htm
Gutierrez, B., Williams, S. & Thieler, R. (2009). Appendix 2. Basic approaches for shoreline change. Retrieved from http://www.epa.gov/climatechange/effects/coastal/app2.pdf
Hammar-Klose, E. & Thieler, E. (2001). Coastal Vulnerability to Sea-Level Rise, A Preliminary Database for the U.S. Atlantic, Pacific, and Gulf of Mexico Coasts. Retrieved from http://geology.uprm.edu/MorelockSite/morelockonline/3_image/cstvulnGoM.htm
IPCC. (2005). IPCC second assessment – Climate change 1995; A report of the Intergovernmental Panel on Climate Change. Retrieved from http://www.ipcc.ch/pdf/climate-changes-1995/ipcc-2nd-assessment/2nd-assessment-en.pdf
IPCC CZMS. (1992). A common methodology for assessing vulnerability to sea level rise. Global climate change and the rising challenge of the sea. Ministry of Transport, Public Works and Water Management, The Hague, The Netherlands, Appendix C.
Klein, R. & Nicholls, R. (1998). Coastal Zones. In: Handbook on methods for climate change impact assessment and adaptation strategies. Retrieved from http://research.fit.edu/sealevelriselibrary/documents/doc_mgr/465/Global_Methods_for_CC_Assessment_Adaptation_-_UNEP_1998.pdf
Klein, R. & Nicholls, R. (1999). Assessment of coastal vulnerability to climate change. Ambio, 28(2), 182-187.
Shaw, J., Taylor, R., Solomon, S., Christian, H. & Forbes, D. (1998). Potential impacts of global sea-level rise on Canadian coasts. The Canadian Geographer, 42(4), 365-79.
U.S. Geological Survey (USGS). (2000). National assessment of coastal vulnerability to future sea-level rise. Retrieved from http://pubs.usgs.gov/fs/fs76-00/fs076-00
This was written for my Biophysical Dimensions of Resource and Environmental Management class.
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