Climate change is a major threat to human health around the world, according to the World Health Organization. The health effects caused by human-driven climate change are intensifying globally. Rising greenhouse gas concentrations result in:
- Increases in temperature and frequency of heatwaves
- Changes in precipitation patterns
- Increases in the frequency and intensity of extreme weather events
- Rising sea levels and flooding
Climate change endangers human health through the air we breathe, the water and food we consume, the weather we experience, and our interactions with natural and built environments. The IPCC AR6 Working Group II report on Impacts, Adaptation and Vulnerability confirms that climate change is already impacting human health across every region, with the burden falling disproportionately on vulnerable populations.
Exposure Pathways
- Extreme Events (heatwaves, storms, wildfires)
- Air Quality deterioration
- Flooding
- Vector-borne diseases
- Water-related issues
- Food security and safety
- Mental Health & Well-being
Effects of Climate Change on Human Health
1. Extreme Events
More frequent and intense extreme events such as heatwaves cause significant illness and death globally. The WHO estimates that between 2030 and 2050, climate change is expected to cause approximately 250,000 additional deaths per year from heat stress, malnutrition, malaria, and diarrhoea alone.
2. Air Quality
Rising temperatures and changing precipitation worsen outdoor air quality, contributing to cardiovascular and respiratory illness, allergies, asthma, and premature death. The WHO estimates that air pollution causes approximately 7 million premature deaths annually worldwide.
3. Flooding
Rising sea levels, extreme rainfall, and storms cause flooding in coastal and urban areas. Health impacts include deaths, injuries, mental health disorders, waterborne illness, and skin conditions. Most urban infrastructure was not designed for current or projected flood levels.
4. Vector-Borne Infections
Changing weather patterns are expanding the geographic range and season of disease vectors, increasing human exposure to Lyme disease, malaria, dengue, encephalitis, hantavirus, West Nile virus, and chikungunya. The CDC Climate and Health program tracks these trends for the United States.
Climate Change: Some Facts and Solutions
5. Water-Related Issues
Climate change alters both the quality and quantity of freshwater available to populations, increasing risk of cholera, cryptosporidiosis, campylobacter, leptospirosis, diarrhoeal diseases, and malnutrition. Research shows that 68% of waterborne disease outbreaks in the US between 1948 and 1994 occurred after extreme rainfall events.
6. Food-Related Issues
Changes in temperature and precipitation directly impact crop yields, food quality, and food safety. Flooding events contaminate drinking water, disrupt wastewater treatment, and amplify pathogen risks from bacteria, viruses, and protozoa.
7. Mental Health and Well-being
The mental health effects of climate change are increasingly documented. Disasters and climate-driven displacement cause stress, grief, behavioural disorders, and social disruption. The CDC identifies mental health as one of the key health outcome areas of climate change.
Adaptation and Mitigation Measures
- Building capacity and resilience of healthcare systems for climate-sensitive diseases
- Leadership and governance commitments at national and subnational levels
- Health workforce capacity building for climate-related health threats
- Strengthening health information systems and early warning systems
- Provision of medical products and technologies to address climate-sensitive diseases
- Efficient, equitable health service delivery systems
- Availability of climate adaptation financing, especially for low-income countries
Related reading: Climate Change and Sustainable Development | Climate Change: Facts and Solutions | Sustainable Development Goals
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