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(2026).
Available soon.
AbstractAs climate change intensifies, private insurers raise premiums to avoid insolvency, compromising the affordability of insurance. This paper studies the economic implications of public reinsurance schemes, designed to enhance affordability in floodplains, and compares them with alternative insurance policies. Unlike private insurers, governments face a low risk of bankruptcy, enabling publicly backed reinsurance programs to offer lower premiums. Using rich administrative dwelling-level geolocated data from France, Belgium, and Switzerland, I first estimate the efficiency costs of public reinsurance due to increased construction in floodplains. I compare risky and safe areas over time, exploiting the staggered implementation of public reinsurance in France and Belgium, and regional variation in Switzerland. I find that, in the absence of public reinsurance, flood damage costs in France would decrease by 4% between 1982 and 2100. I derive the welfare effects of public reinsurance using the reduced-form estimates to calibrate a spatial equilibrium model with an embedded insurance market. Comparing the increase in damage costs from construction in floodplains to the reduction in premiums achieved by transferring risk to the government, I find that public reinsurance substantially improves welfare, by 0.3 to 1.4 billion euros per year, as compared to a subsidized insurance scheme similar to the United States. Conditional on public reinsurance, setting risk-based or uniform pricing has small effects on welfare.