Evaluating the effect of green, blue, and gray measures for climate change adaptation on children’s well-being in schoolyards in Barcelona

• The study evaluates the effect of heat-adapted schoolyards on children’s health. • Students and teachers’ perceptions were assessed using a mixed-method evaluation. • The interventions improved schoolyard appreciation, heat perception, and comfort. • Shaded and seating areas enhanced egalitarian relations and play opportunities. • Urban strategies for climate change resilience should be expanded to other schools. Eleven primary schools in Barcelona were adapted to cope with the effects of climate change under the framework of a European program. Green (vegetation), blue (fountains), and gray (shade structures) interventions were implemented in the schoolyards in 2020. The objective of this study was to assess the impact of these schoolyard transformations on students’ health and its social determinants. A mixed-methods evaluation was conducted: (1) a quantitative pre-post quasi-experimental study using self-reported questionnaires administered to all sixth-grade students from 21 schools (11 from an intervention group and 10 from a comparison group); and (2) a qualitative evaluation through photovoice-based sessions with 11- to 12-year-old students and interviews with teachers from the intervention group. We measured changes in perceptions of the schoolyard environment, play and social behavior, and students’ health and well-being. Data were analyzed using a difference-in-differences approach for quantitative data and a thematic content analysis for qualitative data. After the intervention, both students’ and teachers’ perceptions of the schoolyard environment improved. They reported a decrease in heat sensation and an enhancement in schoolyard attractiveness and naturalization. Additionally, qualitative results suggest that the interventions promoted play opportunities and social inclusion, while reducing conflict behavior. Post-intervention, students also reported increased feelings of relaxation, safety, and physical comfort in the schoolyard. Our findings suggest the effects of the interventions may differ by gender. We identified potential areas for improvement in terms of cooling capacity, safety, water saving, and students’ autonomy. This study supports the need to extend climate adaptations to other schools.