Multiple climate change-driven tipping points for coastal systems.

As the climate evolves over the next century, the interaction of accelerating sea level rise (SLR) and storms, combined with confining development and infrastructure, will place greater stresses on physical, ecological, and human systems along the ocean-land margin. Many of these valued coastal systems could reach "tipping points," at which hazard exposure substantially increases and threatens the present-day form, function, and viability of communities, infrastructure, and ecosystems. Determining the timing and nature of these tipping points is essential for effective climate adaptation planning. Here we present a multidisciplinary case study from Santa Barbara, California (USA), to identify potential climate change-related tipping points for various coastal systems. This study integrates numerical and statistical models of the climate, ocean water levels, beach and cliff evolution, and two soft sediment ecosystems, sandy beaches and tidal wetlands. We find that tipping points for beaches and wetlands could be reached with just 0.25 m or less of SLR (~ 2050), with > 50% subsequent habitat loss that would degrade overall biodiversity and ecosystem function. In contrast, the largest projected changes in socioeconomic exposure to flooding for five communities in this region are not anticipated until SLR exceeds 0.75 m for daily flooding and 1.5 m for storm-driven flooding (~ 2100 or later). These changes are less acute relative to community totals and do not qualify as tipping points given the adaptive capacity of communities. Nonetheless, the natural and human built systems are interconnected such that the loss of natural system function could negatively impact the quality of life of residents and disrupt the local economy, resulting in indirect socioeconomic impacts long before built infrastructure is directly impacted by flooding.

Laterality of exostosis in surfers due to evaporative cooling effect.

OBJECTIVES: 1. To correlate exostosis severity with ear canal evaporative cooling. 2. To assess hearing and complications after canalplasty. STUDY DESIGN: Retrospective chart review. SUBJECTS AND METHOD: A retrospective chart review from 1990 to 2007 at a university tertiary referral center. RESULTS: Surfers from the west coast of the United States were twice as likely to have severe exostoses in the right ear compared with the left. Evaporative cooling from a predominant northerly wind direction during the coldest water temperature months in this region may contribute to this lateral bias because surfers on this coast spend most of their time facing west. Few postoperative complications were identified. No cases of facial nerve injury or entry into the temporomandibular joint occurred. Differences in preoperative versus postoperative pure-tone hearing thresholds were not significant. CONCLUSION: Exostosis severity seems to correspond to the ear that is more exposed to the predominant coastal wind. We propose that evaporative cooling in a cold water environment contributes to greater progression of exostoses in the ear with more exposure to the predominant wind. Exostosis removal using the postauricular approach carries a low complication rate.