5/5 Bottom line: extreme heat is undermining teacher productivity and reshaping learning in ways we’ve totally missed. As heat waves become more common, schools with older workforces or weak cooling systems will be especially vulnerable. Climate change is already affecting American teachers.

3/5 Using matched student–teacher data from North Carolina plus high-resolution weather data, I find each additional extreme heat day lowers test scores in classrooms taught by the teachers aged 54 and over. For younger teachers, I do not find an effect.