Insurance against natural catastrophes: balancing actuarial fairness and social solidarity

Natural disasters offer a specific case study of the mix of public and private insurance. Indeed, the experience accumulated over the past decades has made it possible to transform poorly-known hazards like flood losses, long considered uninsurable, into risks that can be assessed with some precision. They exemplify, however, the affordability issue associated with risk-based premiums. The French scheme reflects such ideas and offers wide coverage for moderate premiums to all, but is questioned in its principle by climate change: we show that some wealthier areas that were not perceived as ‘at risk' in the past have now become exposed to submersion risk. This singularly makes some well-off properties the potential main beneficiaries of a scheme that was historically thought to protect the worst-off. Acknowledging that some segmentation may become desirable, we examine several models for flood risk and the disparity in premiums they entail.