Climate change and health
Climate change affects health through heat, changing disease patterns, extreme weather, displacement and threats to food and water security. The harms are unequally distributed, and action to reduce emissions can also improve health through cleaner air and changes in living conditions.
Direct and indirect health effects
Climate change is a growing global health threat that amplifies environmental health risks. Higher temperatures are associated with dehydration, loss of renal function, skin malignancies, tropical infections, adverse mental health outcomes, pregnancy complications, allergies, and cardiovascular and pulmonary illness and death. Warming can also increase respiratory allergies and asthma and alter the geographical distribution of insect-borne infections, including chikungunya and West Nile disease.
Heatwaves and wildfires cause deaths, while floods and droughts can force people to move within or across national borders. Climate-related disruption can also contribute to civil conflict.
Global heating reduces the yield potential of major crops, while extreme weather and soil depletion hamper efforts to address undernutrition. Destruction of ecosystems erodes food and water security and increases pandemic risk.
Vulnerability and future risk
Children, older people, ethnic minorities, poorer communities and people with underlying health conditions bear disproportionate harms. Countries and communities contributing least to the environmental crisis are often least able to mitigate its effects, while wealth offers no complete protection.
A 2021 assessment reported an increase of more than 50% in heat-related mortality among people over 65 during the preceding two decades. Between 2030 and 2050, climate change is expected to cause additional deaths through malnutrition, heat stress, malaria and diarrhoea.
Health risks occur below 1.5°C of warming above the pre-industrial average; rises above that level increase the chance of natural-system tipping points that could lock in instability and make further harm harder to prevent.
Health benefits and equity in climate action
Investment in climate action can improve health through reduced air pollution, greater physical activity, better housing and healthier diets, while also creating good-quality jobs. Better air quality alone can yield health benefits that offset the global costs of emissions reductions.
Health-journal editors recommend that an equitable response account for countries’ historical and current emissions and their capacity to act. Government action should extend beyond encouraging cleaner technologies to redesigning transport, cities, food production and distribution, financial investment and health systems. Coordination is needed so cleaner technologies do not cause further environmental destruction or exploitation.
Countries contributing disproportionately to the crisis should help lower-income countries build cleaner, healthier and more resilient societies. The editors’ financing recommendations include splitting support equally between mitigation and adaptation, including health-system resilience, using grants rather than loans, building local capabilities, forgiving constraining debts and providing support for unavoidable loss and damage. Such changes should address social and economic determinants of health rather than rely on austerity or perpetuate large inequalities in wealth and power.