Climate change and sex ratios at birth

Jasmin Abdel Ghany , University of Oxford
Joshua K. Wilde, Oxford University
Anna Dimitrova, Vienna University of Economics and Business
Ridhi Kashyap, University of Oxford
Raya Muttarak, University of Bologna

Although human sex ratios at birth (SRBs) shape population composition and are closely linked to maternal health, human SRBs have received little attention in the context of climate change. We examine the effect of temperatures before birth on SRBs by linking Demographic Health Survey (DHS) data on 5.6 million live births in 33 sub-Saharan African countries and India with high-resolution daily maximum temperature data. To identify causal effects, we isolate the quasi-random temperature fluctuations that occur year-to-year, within subnational region and calendar month. We show that in sub-Saharan Africa, extreme heat in the first pregnancy trimester reduces male births by up to 1.1 fewer males per 100 females for a one-standard deviation change in heat days. Particularly vulnerable to heat exposure are women in rural areas, with little formal educational attainment, younger women (15 to 24 years of age), and third and higher parity births. In India, by contrast, heat exposure in the second trimester reduces male births by up to .364% (or .84 fewer males per 100 females). The decrease is driven by higher order (>3) births of women with at least one son. This pattern suggests that when the weather is hot, less sex-selective abortion against girls is practiced by mothers who already have sons. The results point to a context dependent prenatal mortality response to heat exposure that differs by the child’s sex. The findings have important consequences for population composition, reproductive health and inequalities, and gender inequality in the context of global warming.

No extended abstract or paper available

 Presented in Session P11. Climate Change Impacts in the Global South