Extreme heat and poverty can combine to stunt children's development
Riccardo Lennart Nils Meier/Alamy
Young children who experience extreme heat tend to know fewer words, letters and numbers, showing that global warming can wreak havoc on human development in its earliest stages.
Average monthly maximum temperatures of 32°C (90°F) or higher reduced the likelihood that 3- and 4-year-old children would develop normally by 2.8 to 12.2 percent compared with children whose temperatures only reached 26°C (79°F).
“For the first time in the literature, it has been shown that excessive heat affects not only physical health, but also skill development,” says Jorge Cuartas at New York University.
Cuartas and his colleagues studied data from 19,600 children surveyed by UNICEF in Georgia, Gambia, Madagascar, Malawi, Sierra Leone and the State of Palestine. His Early Childhood Development Index tested children's ability to name letters, read simple words and recognize numbers from 1 to 10, as well as other skills.
The researchers compared this to climate data, taking into account factors such as poverty, maternal education and baseline temperatures in the area. Even temperatures as low as 30°C (86°F) began to impair literacy and numeracy. To a lesser extent, heat also impeded children's social, emotional and physical development.
“Even small influences early in life can expand,” Cuartas says. For example, a child who knows fewer numbers may have difficulty learning arithmetic and may fall behind in school.
Heat stress is the leading cause of weather-related mortality. murder almost half a million people annually. A first-of-its-kind rapid assessment of heat-related deaths this year found that the heat wave in June and July killed 2300 people in 12 European cities, mostly people aged 65 and over.
Cuartas and his colleagues found that the effect extended before birth: a temperature of 33°C (91°F) in the first trimester of pregnancy meant the baby was 5.6% less likely to develop properly.
The impact of the heat was greater on children from poor, urban families with no water sources. “Climate change and excessive heat act as threat multipliers. [on] children who are already facing adverse conditions,” says Cuartas.
But the study may not have fully taken into account factors such as violence or political instability that can also hinder children's development, according to Julia Pescarini at the London School of Hygiene and Tropical Medicine.
She said further research should explore how heat affects development. Low-income households may lack air conditioning, or parents may experience more stress when it gets hot.
A better understanding of who is affected and how will allow us to develop adaptation strategies to help them,” says Pescarini.
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