An simplified application of cost-benefit analysis to sea level rise and to the increased risk of storm surges is performed for the Languedoc-Roussillon region of France. This analysis allows to show the interests and limits of cost-benefit analysis. It shows that taking into account the current level of protection is important. It also highlights that cost-benefit analysis is usefull to communicate on the opportunity to rise defenses. However, uncertainty and elements difficult to quantify, such as non monetary amenities prevent the cost-benefit analysis to be the sole basis for decision
