Extremely High Temperatures and Fertility in Italy: A Municipal-Level Event-Based Analysis

This paper analyses the short-term impact of extremely high tempera-tures on fertility in Italy. We build a novel municipality-level panel for 2003–2023 combining birth records from ISTAT with data on extreme monthly average tem-peratures derived from Copernicus. To address the non-random spatial and tempo-ral distribution of climate shocks, we adopt an event-study framework integrated with propensity score matching, balancing treated and control municipalities on pre-treatment fertility dynamics and structural characteristics. The biological lag between conception and birth provides a natural over-identification test for model specification and strengthens causal interpretation. Once comparable municipalities are matched, the estimated effects of extreme temperature events on fertility are small and not statistically significant. Coefficients remain close to zero throughout the post-treatment period. These findings emphasize the importance of accounting for selection and seasonal confound-ing in panel analyses and contribute methodologically to the study of short-term demographic responses to climate variability.