A stunning new study of U.S. high school students finds that heat waves lower their test scores, the effect is greater for minorities, and global warming is going to make things worse in the coming years.
Led by researchers from Harvard and the College Board, this National Bureau of Economic Research study, “Heat and Learning,” provides “the first evidence that cumulative heat exposure inhibits cognitive skill development and that school air conditioning can mitigate this effect.”
The study looked at almost 10 million students who took the PSAT twice (or more) from 2001 to 2014 and compared their scores with daily temperature data recorded by thousands of NOAA weather stations around the country.
Researchers found “hotter school days in the year prior to the test reduce learning, with extreme heat being particularly damaging.” Of course, global warming has already started making temperatures higher: As NASA reported in January, the five hottest years on Earth have all occurred since 2010.
At the same time, global warming has also made extreme heat waves considerably more likely, as many studies have shown.
As the new study concluded, “Without air conditioning, each 1°F increase in school year temperature reduces the amount learned that year by one percent.”
Note that this effect is so big that students retaking the test — who would expect to have similar if not higher scores — actually performed worse the second time if they took the PSAT after a warmer year.
“When we’re hot we get distracted, it’s literally hard to focus because we are physically uncomfortable,” coauthor and Harvard Prof. Joshua Goodman told MarketWatch. “The time students are spending in school that’s hot is literally less good for learning.”
These findings are consistent with considerable research showing that higher temperatures harm worker productivity. For instance, a recent paper by the Federal Reserve Bank of Richmond, “Temperature and Growth”, found that “under the business-as-usual scenario, the projected trends in rising temperatures could depress U.S. economic growth by up to a third.”
The authors of the new study point out that future economic growth will be further undermined because of the loss of cognitive skills by students from global warming.
“Median climate change scenarios for the contiguous United States predict average warming of roughly 5°F by 2050,” the study explains. Thus, students in 2050 will be measurably “less cognitively skilled due to hotter temperatures.”
Again, under Trump’s policies of undermining domestic and global climate action, we face simply off-the-charts heat waves in the coming decades.
The study finds that increased use of air conditioning would mitigate the effect of future warming, but will only cut it in half. So strong action to cut carbon pollution remains a vital strategy.
The authors also conclude that “heat effects account for up to 13 percent of the U.S. racial achievement gap,” in part because “black and Hispanic students live in hotter places than white students” and in part because their schools tend to have less air conditioning.
Again, an effort to upgrade and increase air conditioning in U.S. schools would mitigate some of this problem — although, ironically, that would consume more electricity, which would increase CO2 emissions unless the power came from carbon free sources like renewables.
But we live during a time when the majority party has no appetite for infrastructure spending, and a time when most teachers are buying some school supplies with their own money. We apparently will have to wait for wiser politicians to address both our climate and education problems.