Frying The Brain: The Effect of Prenatal Heat Exposure on Fetal Brain Development

Sammanfattning: Due to climate change, temperatures are rising and are expected to keep rising-leading to an increase in exposure to hot temperatures. This paper presents an analysis of the effects of prenatal exposure to heat on fetal brain development and cognitive abilities later-in-life. Using individual-level data from the Indonesian Family Life Surveys (IFLS) and gridded weather data, the main finding is that exposure to days hotter than 29.5°C affects performance on both short-term and working memory tasks. This effect is even stronger during a critical period of fetal brain development-corticogenesis-suggesting that heat interferes with fetal brain development which affects cognitive abilities later in life. This effect is also larger in urban areas than rural areas. Using employment data, the analysis is extended to also provide tentative evidence on the potential mechanisms behind these effects. It turns out that a higher share of employment in agriculture reduces the effect, an effect that is exclusive to rural populations, suggesting that high temperatures affect the incomes of workers in agriculture positively allowing them to mitigate the negative effects of prenatal exposure to heat. The results imply a growing cost of climate change to human capital formation and productivity, but importantly they also imply that it is possible to mitigate and avoid the negative effects.