Using local knowledge to project sea level rise impacts on wave resources in California

Sea level rise will have significant impacts on many coastal resources. Waves are an important resource in California, where they support the recreation of 1.1 million surfers who inject millions of dollars into local economies. The impacts of sea level rise on wave resource quality, however, are unknown. By examining the local knowledge of more than one thousand California surfers collected through an online survey, this study extrapolates their evaluations to estimate the susceptibility of California surf -spots to sea level rise based on the principle of tidal extrapolation. Vulnerability classifications are derived from the relationship between wave quality, tide effects, and sea floor conditions. Applying these classifications to 105 surf-spots in California evaluated by multiple respondents, we project that as a result of sea level rise by 2100: 16% of surf -spots are Endangered due to drowning; 18% are Threatened, but could adapt if natural shoreline processes are not impeded; and 5% might improve as rising sea levels increase the likelihood they will experience optimal conditions. These projections are significant not only for the many surfers who depend on surf -spots, but also for the coastal communities who rely on the availability of high quality wave resources. Results from this study also have important implications for when and how managers might take surf-spot quality and vulnerability into consideration through coastal adaptation. Lastly, this study establishes a baseline of wave resource quality in California and suggests that this baseline will shift as wave quality changes over the coming century. (c) 2017 Elsevier Ltd. All rights reserved.