High Heat Exposure Affects Early Childhood Development

Climate change – including rising average temperatures and more frequent heatwaves – is widely recognised as a serious threat to the environment, food systems, and human health.

New research now suggests it may also undermine early childhood development, with potentially lifelong consequences.

A study published in the Journal of Child Psychology and Psychiatry finds that young children exposed to higher-than-usual temperatures are less likely to meet key developmental milestones, particularly in literacy and numeracy.

Heat exposure and early childhood development

The research shows that children living in areas where average maximum temperatures exceed 30°C (86°F) perform worse on early learning benchmarks than those growing up in cooler environments.

Specifically, children exposed to sustained high temperatures were less likely to meet basic literacy and numeracy milestones, such as recognising letters, numbers, and simple mathematical concepts.

The study analysed data from 19,607 children aged three and four across six countries: Georgia, The Gambia, Madagascar, Malawi, Sierra Leone, and the State of Palestine. Data were collected between 2017 and 2020 and included household demographics, education levels, health and nutrition, sanitation conditions, climate exposure, and child development outcomes.

To assess developmental progress, researchers used the Early Childhood Development Index (ECDI), which measures milestones across four domains: literacy and numeracy, social-emotional development, approaches to learning, and physical development.

Who is most affected?

The findings reveal that children exposed to average high temperatures above 32°C were up to 6.7% less likely to meet basic developmental milestones than those living in regions with average highs below 26°C. The negative impacts were strongest in literacy and numeracy skills.

Children from poorer households, particularly those living in urban areas with inadequate access to clean water and sanitation, were found to be the most vulnerable. These compounding disadvantages amplify the developmental risks posed by extreme heat.

Why heat matters beyond the classroom

The researchers note that their findings align with earlier evidence linking high temperatures to adverse health and social outcomes. Extreme heat increases the spread of vector-borne diseases, bacteria, and gastrointestinal and respiratory illnesses, all of which can disrupt early development. Temperatures above 34°C also reduce crop yields and increase the risk of food contamination, threatening children’s nutrition and overall health.

Additionally, higher temperatures have been associated with increased levels of stress and violence among adults, indirectly placing children’s safety and well-being at risk.

Jorge Cuartas, the study’s lead author and Assistant Professor of Applied Psychology at NYU Steinhardt, emphasises the broader implications of the findings:

“Because early development lays the foundation for lifelong learning, physical and mental health, and overall wellbeing, these findings should alert researchers, policymakers, and practitioners to the urgent need to protect children’s development in a warming world” (McClain, 2025).

The study underscores the importance of climate adaptation and resilience strategies that explicitly consider early childhood development, particularly in vulnerable communities already facing poverty, food insecurity, and inadequate infrastructure.