Hotter daytimes are thwarting students’ academic progress and exacerbating long-standing educational inequities for people of color, according to researchers who examined the issue in more than 50 countries.

The report, published yesterday in the journal Nature Human Behavior, used two major datasets to track the relationship between students’ exposure to soaring temperatures and their learning outcomes. The data revealed that additional days above 80 degrees Fahrenheit inhibit students’ performance on standardized tests that are meant to measure educational achievement and cognitive ability.

“Temperature has been shown to affect working memory, stamina and cognitive performance, and to lead individuals to reduce time spent engaging in labour activities,” the researchers wrote. “This suggests that, in addition to the channels above, heat may directly affect students’ capacity to learn or teachers’ ability and willingness to teach.”

Co-author Joshua Goodman, a professor of education and economics at Boston University, said the findings have major implications for students who attend classes in buildings that lack proper ventilation and air conditioning. Both in the United States and abroad, he underscored, those schools disproportionately serve low-income families and people of color.

So while it’s already important to ensure school facilities are safe and comfortable, as climate impacts intensify, it will only become more important that older facilities are updated or replaced altogether.

“The returns of doing that,” Goodman said, “are going to get higher over time.”

The researchers worked with two datasets to study academic achievement and temperature across a range of age groups, economies and international borders.

The first dataset examined the test scores of more than 144 million students in nearly 60 countries who took a standardized international exam between 2000 and 2015. The test at issue is administered every three years by the Programme for International Student Assessment and aims to provide comparative, international data on 15-year-olds’ academic performance in reading, math and science.

The second analysis, meanwhile, comprised more than 270 million exam scores of U.S. students between the third and eighth grades. The researchers pulled the exam results from the Stanford Education Data Archive, which standardizes different states’ required annual exams to provide national comparability.

The research revealed that students who went to school during years with additional hot days demonstrated “reduced learning”—and lower test scores. Of particular importance to Goodman was that in the United States, “basically all of the impact of heat on these test score outcomes was driven by Black and Hispanic students, and not by white students. Similarly, by low-income school districts and not by high-income school districts.”

In this way, the two datasets yielded the same conclusion, Goodman said. The learning damage associated with hotter temperatures appear to be larger for low-income populations around the world. That likely means that heat exposure—which is intensifying in step with global warming—will have a more direct and persistent impact on economic growth and development than previously anticipated.

“There are countries where students [already] experience 200 days a year where the temperature is over 80 degrees Fahrenheit,” said Goodman.

So there is an “important component of learning differences between countries, mainly due to the fact that it is literally just harder to learn when you live in a hot place—unless you have air conditioning,” he added.

Reprinted from Climatewire with permission from E&E News. E&E provides daily coverage of essential energy and environmental news at