Potential effects of increased global temperatures on neurological development factors in children under 5 years in east Africa: a modelling study

Abstract

Background A rise in global temperatures is known to reduce calorie and nutrient availability through diminished yields and shifts in crop nutrient content. Insuffi cient calorie and nutrient intake can adversely aff ect nervous-system development in children. To quantify the eff ect of rising temperatures on paediatric neurological development in east Africa, we analysed total intake of calories, iron, and zinc in Kenya, Rwanda, Tanzania, and Uganda. We then used a model to predict the eff ect of rising temperatures on incidences of factors important for neurological development in children younger than 5 years. MethodsWe used data from meta-analyses from the fi elds of climate change, agriculture, economics, nutrition, and neurology referenced in the UN Intergovernmental Panel on Climate Change fi fth Assessment Report and obtained via a Web of Science search in January, 2015. We constructed a model of these meta-analyses to evaluate the eff ect of temperature on yields of all crops; yields on consumption demand elasticity; consumption on caloric intake; and caloric intake on the incidence of undernutrition, stunting, iron defi ciency anaemia in children under 5 years, and population zinc defi ciency. We calculated incidences of nutritional defi ciencies with and without the diluting eff ect of rising atmospheric CO 2 concentration on crop iron and zinc content.Findings Across Kenya, Rwanda, Tanzania, and Uganda, for every 1°C degree of warming we predict that mean calorie consumption would be reduced by 2•20% (95% CI 0•93-3•51); the percentage of undernourished children would increase by 2•40% (1•1-4•1); the incidence of moderate stunting would increase by 12•33% (11•47-13•52) and severe stunting would increase by 6•32% (5•87-6•93). The proportion of children under 5 years with iron defi ciency anaemia is predicted to increase by 1•62% (1•12-2•11) without CO 2 dilution eff ects and 3•00% ( 1•16-4•84) with CO 2 eff ects. The incidence of zinc defi ciency is predicted to increase by 1•20% (0•84-1•56) and 1•88% (0•64-3•13) with and without CO 2 eff ects. At the Paris Agreement target to limit mean global temperature rise to 2°C, we predict total additional cases above baseline (World Bank, 2010) of undernutrition, moderate and severe stunting to be 537 000 (258 000-949 000), 189 000 (91 000-334 000), and 97 000 (46 000-172 000). Compared with World Bank (2010) and Food and Agriculture Organization (2005) baselines, additional cases of iron and zinc defi ciency in children aged under 5 years are predicted to range from 49 000 to 380 000 and 28 000 to 126 000, with Rwanda and Tanzania predicted to have the fewest and most cases in both scenarios.Interpretation Although the combining of meta-analyses will propagate uncertainty, our meta-model is an attempt to quantify the eff ect of rising global temperatures on paediatric neurological development. Our fi ndings could be used in developing countries to support child nutrition programmes, and to justify investment in agricultural productivity and interventions to mit...