Saving Carnival, saving lives: Inside Rio’s heat response

In November 2023, Rio de Janeiro experienced record-breaking temperatures reaching 42°C, with a “real-feel” of nearly 60°C - an event estimated to have caused up to 1,400 deaths. In response, the Centro de Inteligência Epidemiológica (CIE) launched an Extreme Heat Response Protocol in June 2024 to reduce heat stress and related injuries. Integrating meteorological data with hospital admissions and emergency visits, the early warning system can forecast health risks up to three days in advance and trigger alerts. During the 2025 pre-Carnival heatwave, the system activated its second-highest warning level, prompting citywide alerts, opening cooling centers, and stocking clinics as hydration hubs. 

The effectiveness of any alert system hinges upon the degree of coverage and accuracy of the data used for the system. The ability to predict heat indices, forecast health impacts, and trigger responses in advance was a key part of the Extreme Heat Response Protocol process. Data gives cities the opportunity and time to act and prepare. Lastly, the success of the protocol largely stems from the strong collaboration of policymakers, climate scientists, and healthcare leaders.