Global Extreme Weather and Early Childhood Undernourishment

Weather extremes in early childhood can disrupt child growth and nutrition outcomes, but global evidence across developing countries remains limited. We examine the impact of temperature and precipitation variations on early childhood malnutrition across 57 low and middle income countries using over 1.2 million children from Demographic and Health Surveys linked to high-resolution ERA5 weather data. Using bin regression and restricted cubic splines, we identify nonlinear weather effects on stunting, underweight, and wasting probability while controlling for national, seasonal, and regional confounding factors. Our results show that both temperature and precipitation variations increase the probability of childhood malnutrition. We find that temperature has a nonlinear effect on stunting, where both high temperatures (above 90°F) and low temperatures (below 50°F) increase the probability by 1.3-1.4 percentage points relative to moderate conditions. Exposure to heat is associated with underweight and wasting, with months above 90°F increasing these outcomes by 1.2 and 1.0 percentage points, respectively. Precipitation effects vary by outcome type. Drought conditions below 5mm monthly precipitation increase underweight probability by 0.5 percentage points, while heavy rainfall above 250mm increases wasting risk by 0.4 percentage points. Effects vary across child age groups, with temperature showing more precise impacts on stunting among older children, while precipitation effects remain largely insignificant across age groups. Rural children show greater vulnerability to precipitation extremes, particularly for heavy rainfall effects on underweight and wasting.