As India warms, the effects of rising temperatures are increasingly visible in agriculture, labour markets and health. Less visible – but potentially just as important – are the consequences for early human capital formation. If high temperatures reduce children’s ability to concentrate and learn, then climate change may quietly erode the returns to public investment in education.Most of the existing evidence on heat and learning focuses on older students (Garg et al. 2020, Goodman et al. 2020, Zivin et al. 2020, Park 2022). Exam performance declines on hotter days, and cumulative exposure reduces achievement over the school year.Yet early childhood – when cognitive and behavioural foundations are formed – remains underexplored. This matters because skills acquired early in life raise the productivity of later educational investments. If heat disrupts this stage, the effects may persist long after temperatures fall.In new research from the Indian state of Kerala, we evaluate whether a simple, low-cost infrastructure adaptation can protect learning in early childhood learning centres (John et al. 2025). The intervention is modest: applying high-reflective white paint (“cool roof” coating) to the roofs of government-run pre-schools (anganwadis).Heat exposure in early childhood settingsAnganwadis operate under the Integrated Child Development Services (ICDS) scheme and typically consist of single-room concrete structures with limited insulation or ventilation. Children spend roughly four to six hours per day in these spaces. During hot months, solar radiation absorbed by concrete roofs steadily raises indoor temperatures, particularly during late morning and early afternoon.Young children are especially sensitive to heat. Physiological evidence shows that elevated ambient temperature increases brain temperature and can impair neural functioning and attention (Bowler and Tirri 1974, Yablonskiy et al. 2000, Nam et al. 2015). Compared to adults, pre-school-aged children regulate heat less efficiently and tolerate smaller thermal deviations. In such environments, even modest increases in indoor temperature can affect cognitive performance.Despite this, thermal comfort standards are rarely specified in early childhood infrastructure guidelines, and most anganwadis lack mechanical cooling.The intervention and evaluationIn partnership with the Energy Management Centre, Government of Kerala, we conducted a randomised controlled trial across 73 anganwadis in five panchayats in Thiruvananthapuram district. Eligible anganwadis were randomly assigned to treatment (subjected to intervention) or control (not subjected to intervention) groups.In treatment centres, roofs were coated with high-albedo white reflective paint. The objective was straightforward: reduce solar heat absorption and limit heat transfer indoors. The intervention was completed before the peak summer months of 2024.Temperature loggers were installed in all centres to record daily maximum indoor temperatures. We also conducted thermal imaging of roofs and ceilings to measure surface temperatures. To assess human impacts, we surveyed anganwadi staff regarding thermal comfort and administered an age-appropriate puzzle task to children before and after the intervention. Attendance records of children were collected to examine whether cooling influenced participation.Physical and behavioural effectsThe physical mechanism is clear. Thermal imaging showed that treated roofs were approximately 11°C cooler at peak compared to untreated roofs, and ceiling temperatures were about 5°C lower. These surface changes translated into an average reduction of around 1.3°C in daily maximum indoor temperature in treated anganwadis relative to control group anganwadis.Staff in treated anganwadis reported significantly lower heat perception and discomfort during classroom hours. While we did not directly measure productivity, prior research (Malmquist et al. 2021) suggests that improved thermal comfort can mitigate fatigue and stress, potentially improving classroom interactions.For children, we observed measurable improvements in cognitive performance. Performance on a simple puzzle task improved by approximately 6-7% relative to baseline levels in treated anganwadis. The task was intentionally uncomplicated – most children could complete it even before the intervention – which suggests that the measured gains are likely conservative. Under more cognitively demanding conditions, the effects could be larger.Importantly, we found no effect on attendance. Seasonal declines in April and May, combined with a heatwave-related closure during the study period, likely masked any potential participation response. The evidence therefore suggests that cooling improves the quality of time spent in classrooms rather than increasing the number of days attended.Cost-effectivenessThe intervention cost approximately Rs 19,500 per anganwadi, inclusive of materials and labour. Assuming a conservative lifespan of five years and modest annual maintenance costs, this amounts to roughly Re 1 per child per day in a typical anganwadi serving 15 children.For comparison, cooling a similar space using air-conditioning would cost around five times more per child per day in electricity alone, in addition to requiring reliable power supply and increasing energy demand. Passive cooling through reflective paint, by contrast, involves no ongoing energy use and minimal emissions.Placed alongside existing ICDS expenditures – including Rs 8 per child per day for supplementary nutrition at the Union government level (with higher allocations in many states) – the cost of thermal adaptation is modest.Policy implicationsThe results have two major implications.First, climate adaptation in education need not rely solely on expensive technological solutions. Building-level improvements that reduce heat exposure can generate measurable learning benefits at low cost. As heat extremes become more frequent, such adaptations may protect the returns to public spending on early childhood development.Second, early learning environments deserve greater attention in adaptation planning. Investments in nutrition, teacher training and curriculum aim to improve cognitive outcomes. If environmental conditions systematically undermine children’s ability to concentrate, these investments become less productive.Passive cooling does not replace broader infrastructure reforms, but it complements them. Incorporating reflective roofing standards into construction and renovation guidelines for anganwadis could be achieved within existing administrative frameworks.In a warming climate, protecting early cognition is not only a health or comfort issue; it is a human capital strategy. Small adjustments to public infrastructure today may help preserve the long-run returns to education in the future.Benston John is with St. Stephens College, E. Somanathan with the Indian Statistical Institute and Rohini Somanathan with the Delhi School of Economics.This article has been republished from Ideas for India. Read the original article.