Macroeconomic impacts of local population dynamics and acute climate events: a 20-year global perspective

Local economies worldwide are largely influenced by fundamental population dynamics including migration. Climate change is a growing threat to macroeconomic stability through both the direct damage from acute hazards and the indirect pressures of climate-induced migration. This study examines two distinct forms of macroeconomic vulnerability via: (1) local population change and (2) exposure to severe climate events. We used globally available, high-resolution spatial data (12.5 km) from 2000 to 2020, including population, gross domestic product (GDP), median age, poverty (deprivation index), human development index (HDI), and annual flood and fire metrics. We first assessed how economic and sociodemographic indicators shifted with population change over 20 years. Then, using a difference-in-differences approach, we estimated annual GDP changes in the ten years following a severe flood or fire. Analyses were stratified by global economic region (developed, emerging, and developing) and urban–rural context. Population growth was significantly associated with GDP gains, particularly in urban, developed regions (0.91–1.04% increase per 1% population growth). Increased population was also linked to younger age, lower poverty, and higher HDI (except in some rural and developing regions). Rural, least developed regions experienced the largest and most persistent GDP losses following floods. Rural areas in Brazil, Russia, India, and China experienced the greatest impacts after fire exposure—with maximum GDP losses of 1.1% in years 0–3, 5.6% in years 4–6, and 9.3% in years 7–10. This analysis provides critical insight into the relative vulnerabilities of local economies—while population change drives long-term economic shifts in developed urban regions, rural areas in developing and emerging economies are highly vulnerable to acute macroeconomic shocks from climate extremes.