Health and Climate Change

An assessment carried out the World Health Organisation in 2018 concluded that climate change is expected to cause approximately 250,000 additional deaths globally per year between 2030 and 2050: 38,000 due to heat exposure in elderly people, 48,000 due to diarrhoea, 60,000 due to malaria, and 95,000 due to childhood undernutrition. A recent study¹ which Claudia contributed to, showed there has been a 53-7% increase in heat-related mortality in people older than 65 years during the past 20 years, reaching a total of 296,000 deaths throughout the world in 2018.

This and other studies support the conclusion that climate change has an impact on our life expectancy.

This data is sobering but there are many other ways that climate change can and will affect our physical and mental health, both directly and indirectly.

Infographic illustrating how climate change can impact various aspects of health © American Public Health Association (APHA). Click to expand.

Physical Health Effects of Climate Change

• Heatwaves: Deaths result from heat stroke as well as from cardiovascular, kidney and respiratory diseases. During a heatwave, hospital admissions for these disorders increase significantly putting pressures on local health services.
• Wildfires and floods: Long periods of extreme heat are associated with droughts and dry conditions which can drive wildfires. Wildfire smoke reduces air quality, both locally and in areas downwind of fires, and is responsible for increasing hospitalisations and medication dispensations for respiratory diseases. Severe weather events such as wildfires, flash floods and flooding can harm and kill those directly exposed to them.
• Allergies: The warming climate also makes allergies worse. Higher temperatures mean plants produce pollen for longer periods and higher carbon dioxide concentrations can increase growth in plants such as grass intensifying the allergy-causing effects of the pollen.
• Diseases: Insect carriers of diseases such as malaria, Zika virus and dengue are expanding their geographical ranges due to changes in temperature and rainfall patterns. Higher temperatures are linked with salmonella and campylobacter outbreaks as well as algae blooms which cause gastrointestinal problems and the incidence of waterborne cholera which increases with drought.

Nutrition, work productivity, infectious diseases and migration are some of the indirect ways in which climate change is affecting human health. Rising temperatures lead to declining crop yields and carbon dioxide emissions lower their nutritional density; fish and marine organisms migrate to new areas in response to changes in ocean temperature, affecting traditional fishing industries; and productivity is impacted by the number of hours it’s heat-safe to work outdoors. Sea level rise threatens low-lying island nations and coastal populations which may be forced to migrate when areas become uninhabitable.

Climate Change and Mental Health

Climate change comes with a mental health risk too. Anxiety and post-traumatic stress disorder are observed among people affected by floods and heatwaves. Grief, loss and strains on social relationships occur in communities affected by natural disasters and high-risk coping strategies such as increased alcohol use, substance abuse, stress and depression may be seen in individuals impacted by events linked to climate change. The health of the community also suffers, with increased interpersonal aggression, violence and crime, increased social instability and decreased community cohesion.

Extreme heat is also linked with aggression, violence and suicide. Some psychotropic medications may interfere with the body’s ability to efficiently regulate its temperature, increasing vulnerability to heat. Less well understood but also significant is the distress caused to many by environmental degradation and displacement, and the anxiety and despair that knowledge of climate change might provoke.

Climate Change: a Positive Response

But there are reasons to be positive. Communities, health systems and governments around the world are responding to the impact of climate change on our health with strategies and resources. Read the Mitigation Actions and Health Co-Benefits section which explains why tackling climate change presents an enormous health opportunity as so many of the mitigation and adaptation interventions bring benefits for human health and wellbeing in the form of cleaner air, healthier diets and more liveable cities.

A new generation of architects, engineers and planners are doing just this by working to transform our cities. This includes green spaces which make us less exposed to air pollution and provide local cooling (cities are usually warmer than their rural surrounding because of human activities) and places to interact with other people and do physical activities to reduce stress and improve mental health.

Have you read any recent news stories about the impact of climate change on human health? You may find it helpful to make a note of these to help inform and give real-life context to your studies.

1. The 2020 report of The Lancet Countdown on health and climate change: responding to converging crises. Nick Watts et al. The Lancet Vol 397, P129-170, January 09, 2021

Author: Dr Claudia Di Napoli, School of Agriculture, Policy & Development