Rising global temperatures are not only threatening ecosystems, food security, and adult health. New research shows that extreme heat can also slow early childhood development, affecting children even before they reach school age. The findings add to a growing body of evidence that climate change is now influencing some of the earliest stages of human life.
In a study published in the Journal of Child Psychology and Psychiatry, December 2025 and summarized by ScienceDaily, researchers found that children aged three to four who grow up in hotter environments are more likely to experience delays in acquiring basic skills such as reading and counting. The effect was observed consistently across countries with varying social and economic conditions, particularly in low-income regions with warmer climates.
“Heat is not just a physical discomfort,” said Jorge Cuartas, the study’s lead author and a professor at New York University. “For young children, continuous exposure to high temperatures can disrupt critical processes in early brain development.”
The study analyzed data from nearly 20,000 young children across six countries: Gambia, Georgia, Madagascar, Malawi, Palestine, and Sierra Leone. Researchers combined child development data collected through the Early Childhood Development Index with local climate records to examine how temperature patterns relate to early learning outcomes. The analysis revealed a strong association between higher daily maximum temperatures and lower levels of cognitive development.
Children living in areas where average daily maximum temperatures exceed roughly 30 degrees Celsius were significantly less likely to reach key developmental milestones than those growing up in cooler environments. The largest gaps were found in early literacy and numeracy skills, which are widely recognized as the foundation for long-term educational success.
Cuartas explained that early childhood is an especially sensitive period for brain development. During these years, the brain grows rapidly and is highly responsive to environmental conditions. Excessive heat can interfere with sleep quality, increase stress levels, and reduce a child’s ability to focus, play, and engage in learning activities.
“When children struggle to sleep because of heat or feel physically uncomfortable throughout the day, their opportunities to learn through play and social interaction are diminished,” Cuartas said.
The impact of heat exposure does not occur in isolation. The study found that high temperatures had a far stronger effect on children living in disadvantaged households. Limited access to clean water, poor housing ventilation, and the absence of cooling systems such as fans or air conditioning leave children in low-income families more exposed to extreme heat.
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In many lower-income countries, households lack even basic means of cooling. Children spend much of their time indoors or in surrounding environments where temperatures remain high, often with little relief. According to the researchers, these conditions create a climate-related inequality that has received little attention in global discussions.
“Climate change threatens to widen existing gaps in early childhood development,” Cuartas said. “The children who contribute the least to global emissions are often the ones bearing the greatest burden of its consequences.”
The study also found that developmental delays can occur even in the absence of extreme heat waves. Modest increases in average daily temperatures, when sustained over long periods, were still associated with measurable declines in developmental outcomes. This suggests that the effects of climate change on young children may be broader and more pervasive than previously understood.
Researchers warned that delays in early development can have lasting consequences. Children who enter school already behind in basic skills face higher risks of academic difficulties later in life, which can ultimately affect their educational attainment, income potential, and long-term health.
Although the study does not establish a direct causal relationship, the consistency of the findings across multiple countries strengthens the case that heat exposure is a significant risk factor for early childhood development. The authors describe the results as an early warning for policymakers, particularly in regions expected to experience the most severe temperature increases due to climate change.
Cuartas and his colleagues argue that climate adaptation strategies must begin to address the needs of young children. Simple interventions such as improving home ventilation, creating cooler learning spaces, and ensuring access to clean water and sanitation could help reduce the impact of heat on early development.
“Protecting children in early childhood is a long-term investment in society,” Cuartas said. “If we fail to account for the effects of climate on young children today, we risk facing generations with greater developmental challenges in the future.”
The findings add a new dimension to the global climate debate. Until now, rising temperatures have largely been discussed in terms of heat-related deaths, reduced labor productivity, and physical health risks. This research shows that climate change is also affecting a quieter but more fundamental domain: the cognitive development of children who will shape the world’s future.
As global temperatures continue to rise, researchers warn that without serious mitigation and adaptation efforts, millions of children worldwide could face developmental obstacles from their earliest years. For them, climate change is no longer a distant threat, but a reality already shaping how they grow, learn, and experience the world. (Wage Erlangga)
