Adapting urban areas to rising temperatures: Strategies to reduce heat and vulnerability in a warming world

The need for cities to prepare for the increasing frequency, persistence, and intensity of heat waves (HWs) makes modeling these events essential for evaluating the effectiveness of heat adaptation strategies. We use the Pseudo Global Warming (PGW) method to project HW episodes that are simulated with the Weather Research and Forecasting (WRF) model coupled with the Building Effect Parameterization and Building Energy Model at 1 km resolution using the Metropolitan Area of Barcelona (AMB) as a case study. We assess three plausible urban adaptation strategies to reduce temperatures, heat stress and vulnerability to heat now and in mid- and late- 21st century conditions under the SSP370 radiative forcing scenario: 1) increasing rooftop albedo by white-painting all feasible rooftops; 2) implementing irrigated sedum green roofs where possible; and 3) increasing peri-urban agriculture, urban parks, and urban fraction while reducing urban forest according to the recently approved Urban Master Plan. We find that (1) provides the greatest cooling (−1.75 °C during daytime) in the most vulnerable areas, while (2) and (3) show moderate regulation (−0.37 °C and − 0.26 °C respectively) and slight nighttime warming (0.24 °C and 0.31 °C). Despite these reductions, none fully counterbalance the projected 6 °C increase by 2100, highlighting the limited capacity of adaptation strategies under severe warming scenarios and providing critical insights into effective and feasible measures to mitigate heat impacts and reduce vulnerability in urban environments.