The Future of Atmospheric Heatwaves in Chile Projected by a Regional Climate Model

Heat waves pose a threat to human health, energy services and ecosystems. We use the CNRM‐ALADIN regional climate model (12.5 km resolution) to quantify projected changes in duration, intensity, frequency and magnitude of heat waves in Chile this century under two high‐emission scenarios. Temperatures were bias‐adjusted using the unbiased quantile mapping (UQM) method. We estimate seasonal heatwave and cold spell evolution in three Chilean cities (La Serena, Santiago, Concepción), analyse cold wave evolution and estimate heat wave risk ratios. In Santiago, projections indicate that by the warm season extends from late November to early April, a increase. The heatwave period will extend at days per decade to cover over 6 months by 2080, with potential occurrences from September to April and the cold season is expected to disappear. This contributes to a increase in heat wave frequency in Santiago between – and –. Projected heat waves in Santiago exceed 50 days in duration, are up to 3°C more intense and have magnitudes greater than the historical climate. The annual most intense heat wave is expected to be more intense and 2.8 times the magnitude. Risk ratio analysis suggests heat waves surpassing Santiago's historical annual maximum will occur 6 to 8 times more frequently.