Projections of temperature extremes and heatwaves in Goiânia, Brazil: intensity, duration, and persistence under CMIP6 scenarios

Abstract This study assessed changes in maximum air temperature, daytime and nighttime extremes, and heatwaves in Goiânia under SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5 for 2021–2040, 2041–2060, and 2081–2100. Daily NEX-GDDP-CMIP6 series from 31 global climate models were aggregated over the municipality; maximum temperatures were evaluated against ERA5 and INMET observations. Mean daily maximum-temperature changes used the 1995–2014 baseline; extremes used 1985–2014. Heatwaves comprised at least six consecutive days above model- and calendar-day-specific historical P90 thresholds. The multimodel median summarized projections, with performance weighting as a sensitivity analysis. In 2081–2100, median warming ranged from 1.24°C under SSP1-2.6 to 5.15°C under SSP5-8.5, reaching 6.96°C in October under the latter. Median annual heatwave-day increases were 44.60 and 260.60 days, respectively; warm-night frequency increased by 75.69 percentage points under SSP5-8.5. Weighting reduced this scenario’s median warming from 5.15 to 4.70°C. Longer heatwaves and greater hot-day persistence indicate substantial changes in Goiânia’s temperature-extreme regime, especially under SSP5-8.5.