Taking extreme heat as an example, the authors note that preterm births–the leading cause of childhood deaths–spike during heatwaves, while older people are more likely to suffer heart attacks or repository distress. Each additional 1°C in minimum daily temperature over 23.9°C has been shown to increase the risk of infant mortality by as much as 22.4%.

“These studies clearly show that climate change is not a distant health threat, and that certain populations are already paying a high price,” said Dr Anshu Banerjee, Director of Maternal, Newborn, Child and Adolescent Health and Aging at the World Health Organization ( WHO) in a statement issued on Wednesday.

Authored by experts from WHO and academics from around the world, the collection, titled Climate Change across the life course, reports several specific physical and mental health impacts that arise due to different climate hazards. For example, high temperatures are associated with adverse birth outcomes, primarily preterm birth and stillbirth, as well as hypertension in pregnancy and gestational diabetes. Heatwaves affect cognitive function and therefore learning for children and adolescents, while increasing heart attacks and respiratory complications among older people.

Ambient air pollution is associated with hypertensive disorders (high blood pressure) during pregnancy, low birth weight and preterm birth, and impacts fetal brain and lung development. It is also strongly associated with an increased risk of infant death and adverse birth outcomes. Respiratory disorders increase among children and older people, who also face greater risks of cancer, cardiovascular disease, and pneumonia. Climate-related natural disasters have significant mental and physical health impacts. Flooding and drought reduce access to safe water and food supplies, increasing diarrheal diseases and malnutrition. Wildfires have been shown to increase respiratory disorders and cardiovascular mortality rates for older people, as per the report.

While climate change affects everyone, climate-related displacements and disruptions have severe consequences for those needing regular access to health services and social support. Infants and older people as well as pregnant women may have particular physiological risk factors, such as difficulties with temperature regulation, vulnerability to dehydration, and/or weaker immune systems. They also face disproportionate impacts from the indirect effects of climate change and related disasters, like food and water shortages and spikes in vector and water-borne diseases.

“A healthy environment underpins health throughout life, enabling healthy growth and development in childhood and adolescence, healthy pregnancies and healthy aging,” said Anayda Portela, scientist at WHO and an author on the papers. “There is an urgent need to mitigate climate change by reducing greenhouse gas emissions and to build climate resilience; to take specific actions that protect health at these various life stages, and to ensure continuity of health services for those most at risk when climate disasters occur.”