Hazards threaten coastal communities and ecosystems over a wide range of spatiotemporal scales. One of the most pressing concerns for coastal property owners, decision makers, and researchers is the uncertain role that a changing climate will have on the intensity and frequency of these hazards. The significant uncertainties associated with both projected rates of global sea level rise (SLR) and the potential for continued trends of increasing wave heights and changes to storm tracks has made the task of incorporating the impacts of climate change into coastal vulnerability assessments challenging. Within this context of this uncertainty, we present a methodology to directly incorporate the impacts of climate change and variability into coastal vulnerability assessments via an integrated multi-scale, multi-hazard approach. Our quasi-probabilistic technique integrates two coastal hazards (dune overtopping and coastal erosion) over a time scales ranging from individual storm events to multidecadal trends influenced by a variety of climate change scenarios. Since both SLR and changes in storminess have the potential to exacerbate the extent of vulnerable stretches along a coast, these two climate controlled factors are integrated into projections of local total water levels (wave runup plus tides) to assess the relative strengths of their influence on flood and erosion hazards. Despite underlying uncertainties associated with future climate conditions, coastal decision makers need to begin planning for a changing climate now. Therefore, we use a suite of recently published semi-empirical global SLR predictions to develop scenarios of future conditions. The potential for continued changes in storminess is accounted for by developing a range of wave climate scenarios based on decadal observations from regional wave buoys. While this approach has been developed for dune backed coastlines in general, discussed here is application of the technique to a 14 kilometer stretch of the dynamic Northern Oregon coast along which significant coastal erosion and flood hazards are currently perceived. By using simple models to predict the possibility of coastal dune overtopping and the extent of coastal erosion from storm events we can quantitatively assess the relative influence of climate change trends based on projections at various future planning horizons. Incorporation of these future hazard probabilities into the development of coastal hazard maps can provide science-based support to allow prioritization of resource allocation to best prepare coastal communities, fragile ecosystems, and jeopardized infrastructure which are likely to experience accelerated vulnerability due to a changing climate.

Authors: 
Erica L. Harris
Short Description: 
Methodology to directly incorporate the impacts of climate change and variability into coastal vulnerability assessments via an integrated multi-scale, multi-hazard approach.
Product Number: 
ORESU-Y-11-003
Entry Date: 
Friday, May 17, 2013
Price: 
Free
Length: 
Online, 91 pp.
Size and Format: 
8 1/2 x 11, online
Department/University: 
Oceanography, Oregon State University
Degree: 
Master of Science
Year of Publication: 
2011
How to Order: 

Available online from the National Sea Grant Library