Cooling the Crisis: How Juntos Helps Students Learn Despite Rising Temperatures

A groundbreaking study by the World Bank’s Environment Global Department, in collaboration with the Pontificia Universidad Católica del Perú (PUCP) and the Instituto de Estudios Peruanos (IEP), exposes a hidden but alarming threat to education in Peru: rising temperatures. The research, authored by Juan José Miranda and Cesar Contreras, uncovers how heat waves are steadily undermining learning outcomes for children, especially in the country’s under-resourced public schools. Drawing from national testing data and granular climate metrics, the study finds that even a modest increase of just 1°C above 20°C results in a 7% drop in math and 6% drop in reading scores, measured as a fraction of a standard deviation. When temperatures climb above 22°C, the impact is even more severe, with math and reading outcomes falling by 13% and 8% respectively. These losses amount to erasing weeks of academic progress, particularly for Peru’s most vulnerable children.

A Country Rich in Climates, But Poor in School Readiness

Peru’s extraordinary geographic diversity makes it an ideal setting for examining how climate impacts learning. The country hosts 84 of the world’s 117 life zones and 28 of 32 recognized climate types, ranging from tropical lowlands to high-altitude Andean zones. Yet this natural diversity is matched by glaring inequalities in educational infrastructure. More than 70% of schools lack access to adequate water services, 20% have no electricity, and fewer than half are connected to sewage systems. The majority of public schools are also in poor physical condition, with limited internet connectivity and substandard classroom environments. This lack of basic infrastructure severely limits adaptation options, such as air conditioning or thermal insulation, that are available in wealthier nations. The government has introduced targeted programs like Plan Selva to address these gaps in the Amazon region, but their coverage remains far too narrow to cope with the national scale of climate exposure.

The Chilling Effects of Heat on Cognitive Performance

The study uses data from Peru’s Student Census Evaluation (SCE), which tested second-grade students between 2007 and 2016, and overlays this with ERA5 weather data to measure temperature exposure leading up to exam dates. The researchers focused on “cooling degree days” (CDDs), the cumulative number of degrees above a 20°C baseline, to assess how extended exposure to heat affects learning. The results are stark: every additional cooling degree day corresponds to a measurable decline in test performance. Interestingly, moderate increases in temperature appear to help slightly in colder zones, reflected through “heating degree days,” but the overwhelming effect of high temperatures is clearly negative. Students exposed to more CDDs are significantly more likely to fall into the bottom 25% of their class academically and much less likely to land in the top quartile, tightening the grip of inequality.

The impact doesn’t vary significantly by gender, but students in schools with access to basic services like electricity and water showed marginally smaller learning losses. Still, these infrastructure buffers were not strong enough to fully counteract the detrimental effects of extreme heat. The data also revealed that temperature effects were most pronounced during the three to six months leading up to exams, precisely when instructional time is most crucial, while heat waves during summer breaks had little to no effect.

Cash Transfers as a Lifeline: The Role of Juntos

In an encouraging twist, the study explores how social policy might blunt the worst effects of climate shocks. It evaluates the Juntos Program, Peru’s flagship conditional cash transfer initiative that provides bimonthly payments to the poorest families on the condition that their children remain enrolled in school. The results are compelling: for every year a student is exposed to Juntos, the negative impact of heat on test performance is reduced by 17% in math and 12% in reading. In schools with high attendance rates, above the 65th percentile, the mitigating effect jumps to 40%, making Juntos one of the most effective tools in the country’s policy arsenal to shield education from climate risk.

Even more impressive is Juntos’ influence on school attendance. Using additional datasets from 2014 to 2016, the study finds that higher temperatures generally reduce student attendance. But students receiving Juntos benefits are more likely to continue attending school during hot spells, offering continuity in learning that helps offset the cognitive burdens of heat. This protective effect of Juntos echoes findings from Mexico’s PROGRESA program but is even more pronounced in Peru, likely due to the country's heightened climate vulnerability and deeper infrastructural challenges.

Toward a Resilient Education System

While the Juntos Program offers a powerful lifeline, the researchers stress that it cannot fully compensate for weak school infrastructure. Financial incentives alone cannot cool sweltering classrooms or replace missing water systems. The authors argue for a dual approach: expanding and strengthening social programs like Juntos while simultaneously investing in climate-resilient infrastructure. Schools need better ventilation, access to clean water, electricity, and ultimately climate-adaptive buildings, especially in low-income regions where vulnerability is highest.

The research offers critical insights for policymakers not just in Peru but across the developing world. As climate change intensifies, its impact on education could quietly undercut decades of progress in human capital development. Peru’s experience suggests that integrating targeted social protection with infrastructure reform can form a robust defense against the creeping threat of climate-induced learning loss. The classroom may be an unexpected front line in the battle against climate change, but as this study makes clear, it is one we cannot afford to ignore.