Economie expérimentale et acceptabilité des politiques publiques : une étude de cas (le risque de submersion marine en Languedoc-Roussillon)

Can experimental economics provide useful insights for public policies making? We study the acceptability of the strategic retreat solution in order to cope with coastal flooding risks in the Languedoc-Roussillon region (France) . This solution consists in an organized retreat of infrastructures and housings to the hinterland. Two questions are treated. What is the degree of solidarity among individuals exposed to the risk compared to those who are not? Is solidarity function of the distance to the risk? Our experimental protocol shall answer these questions. Using a variant of the solidarity game , laboratory and eld experiments allow us to analyze solidarity preferences. Data were gathered among 5 cities of the Herault region (France): Valras-Plage, Vendres-Plage, Béziers, Murviel lès Béziers and Saint-Chinian. These data give individuals' perceptions (coastal attachment, environmental risks) as well as socio-economical aspects and stakeholders opinions. Data collected from these surveys show that individuals have no memory of the risk worse, they are unaware of it. Thus, the adaptive public policy, such as the strategic retreat solution, tends to be unacceptable. Beaches are mostly perceived as recreational areas, not as protective shields against coastal flooding. Therefore, in terms of public communication an emphasis should be put on the protective role of beaches. Preliminary laboratory results show that the strategic retreat solution can't be funded on solidarity alone. In contrast, fields experiments show more solidarity. However, we can't yet conclude if whether or not this solidarity level will be reached when individuals will have to face these disasters. Solidarity is higher among individuals close to the risk. Thus, solidarity is essentially a local phenomenon. To sum up, the private financing of flooding risk consequences solely on solidarity is not possible. In any case, an analysis of the speci c determinants of solidarity (anonymity, knowledge of the risk, personality traits) [62, 40, 74, 66] is required if one want to use it to finance this endeavour. A deeper analysis should be made about information and individuals' behaviour [63, 64]. These analyses should provide useful insights to quantify the fundraising amount collected in function of policy maker speeches, including the optimal tax rate in order to complete the financing. However, existing cost-benefit analyses of the literature should be completed to include the "ecoplage" solution as well, which has not been done yet.