Heatwaves in the Northern Brazil Region: Current and Future Perspectives

ABSTRACT Heatwaves (HWs) characteristics (number, frequency and duration) in state capitals of the Northern Brazil Region (NBR) and their climate projections throughout the century were analysed using observed data from meteorological stations and Regional Climate Models (RCMs). HWs were identified considering a minimum period of three consecutive days during which the daily maximum temperature exceeds the 90th percentile. Results showed that more than 125 HWs were recorded in each NBR capital between 1980 and 2019. On average, these HWs were observed over a span of 17–21 days per year, with individual events typically lasting between 3 and 5 days. In the last four decades (1980–2019), the number of HWs as well as their frequency and duration have increased over the NBR. Regarding the model's performance, the HWs characteristics could be reasonably reproduced by the ensemble generated by the RCM from the CORDEX‐CORE. However, the errors found led us to apply a bias‐correction method to produce a fair indication of the future changes. In a future perspective considering the most pessimistic scenario (RCP8.5), HWs are projected to increase in number, frequency, and duration in almost all capitals, with these conditions expected to worsen by the end of the century. The projected intensification suggests that the number of HWs could more than double in most NBR capitals, while the increase in frequency and duration can exceed 600% and 300%, respectively. These regional projected changes reinforce the need for deep, rapid and sustained mitigation and accelerated implementation of adaptation actions to contain and reduce global warming and its related impacts and risks for humans and ecosystems.