A new study has correlated warmer air temperatures with lower test scores among Black and Latinx students in the United States, likely because they’re less likely than their white peers to have air conditioning in their homes or—most notably—their schools.

“Being exposed to higher temperatures throughout the school year appears to take a gradual and cumulative toll on those students’ ability to absorb their lessons,” lead author R. Jisung Park, assistant professor of public policy at the University of California, Los Angeles, told the New York Times. The study, just published in the journal Nature Human Behaviour, found that students who experienced more school days reaching 27°C or warmer over a year got poorer test scores than those at schools in the same districts who faced fewer hot days.

The study examined “more than 270 million state-administered test scores for third to eighth graders between 2009 and 2015,” writes the Times. Park and his team were careful to account for other factors that might inhibit learning in youth from minority communities, such as lack of access to tutoring. Co-author Joshua Goodman, an associate professor of education and economics at Boston University, confirmed that poor HVAC and ventilation are commonplace in the schools typically attended by low-income students.

This is just the latest in a slew of studies confirming that “climate change in general, and rising temperatures in particular, have a greater effect on minorities”. One study linked the history of redlining to the urban heat island effect, the Times notes, while another connected pre- and post-natal birth problems to high temperatures and air pollution, with Black mothers and babies generally “harmed at a much higher rate than the population at large.”

“The growing body of research showing those disproportionate effects has changed the public conversation around climate change, directing more attention to racial equity,” said Nsedu Obot Witherspoon, executive director for the Children’s Environmental Health Network. However, she told the Times she is not hopeful that the data will translate into policy changes.

“We’ve been discussing a lot of this for a very long time,” she said.