Taxe ambiante : un outil adapté à la lutte contre les coulées de boue ? Une étude expérimentale

[paper in French] Recent surveys report the increasing number of muddy flows and point out the fact that agricultural practices (among others) play an important role in their occurrence. We propose to use an ambient tax/subsidy instrument to induce farmers to adopt better practices. The advantage of this type of instrument is that it allows the regulator to introduce the correct incentives without needing the observation of the agents’ individual efforts, but only of the collective result of efforts. Our first objective is to test the efficiency of the instrument in the specific context of muddy floods. Our second objective is to investigate the acceptability of this scheme. We run our experiment with six real farmers and carry out a socio-economic debriefing after the experiment. We observe that the instrument is relatively efficient at least in the first part of the experiment. However, the debriefing reveals subjects’ scepticism about the usefulness of the experimentation for investigating their real behaviour and that they are against this type of instrument.