Five key links between climate change and health
As the latest IPCC report on how climate change is affecting the world shows, the consequences of a rapidly warming earth are devastating to human health. We need urgent action
- 22 March 2023
- 5 min read
- by Priya Joi
Human activity has warmed the planet by 1.1°C which has caused unprecedented changes to the Earth's climate, according to the latest Intergovernmental Panel on Climate Change (IPCC) report released this week.
From rising sea levels to more extreme weather events to fast disappearing sea ice, the planet is changing quicker than people and animals can adapt to the change, leading to significant damage to our health and wellbeing.
High temperatures, and especially heatwaves, have several negative effects on mental health such as a rise in depression and anxiety, and there is a proven link between rising temperatures and suicide attempts.
Moreover, certain populations, such as the elderly, children and those with existing health conditions, are particularly vulnerable to the impacts of climate change. Additionally, low-income communities and indigenous populations may be disproportionately affected by climate change because of limited access to healthcare and greater exposure to environmental hazards.
The good news is that despite these devastating consequences, there remain "multiple, feasible and effective options to reduce greenhouse gas emissions and adapt to human-caused climate change, and they are available now," said scientists writing in the IPCC report.
The report calls for the mainstreaming of health into food, infrastructure, social protection, and water policies, including strengthening public health programmes, increasing health systems resilience, reducing exposure of water and sanitation systems to flooding, improving surveillance and early warning systems and vaccine development.
What it requires is significant individual and government commitment to reversing some of these effects of climate change on human health – here are five key links between the two.
1. Greater spread of insect-borne diseases
Rising temperatures and changing rainfall patterns are enabling the increased spread of diseases such as malaria, dengue, West Nile virus and Lyme disease as the mosquitoes and other insects that carry them are able to expand their habitat. For instance, changing temperature and rainfall across Africa could increase yellow fever deaths by up to 25% by 2050.
Data suggests that malaria-carrying mosquitoes have already been able to move into more temperate regions, and over the past century have elevated their range by about 6.5m per year and away from the Equator by 4.7km every year. A malaria vaccine is now being rolled out in high-risk areas, and while a dengue vaccine is available, it is not accessible worldwide.
2. Water and food scarcity can mean malnutrition and greater disease
Climate change can affect the availability and quality of water and food resources. This can lead to dehydration and the spread of water-borne diseases as clean water becomes even more scarce – about half the global population currently contends with severe water scarcity for at least one month per year.
Global warming can also affect crop yields, which can lead to food shortages and price increases, which leads to malnutrition. Being undernourished weakens the immune system, putting people at greater risk of disease, making it even more important to ensure routine immunisation against key childhood diseases, and to be able to respond to outbreaks of vaccine-preventable diseases such as cholera.
3. Increasingly poor air quality can cost lives
Warmer temperatures can lead to increased ground-level ozone formation and worsened particulate matter pollution. And this isn't just a few parts of the world that might be perceived as polluted – according to the United Nations Environment Programme (UNEP) in 2019, 99% of the world's population was living in places where the WHO's 2021 air quality guidelines were not met.
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Poor air quality can have significant impacts on human health. Pollutants in the air can cause respiratory problems and exacerbate existing conditions such as asthma and make people more vulnerable to diseases like COVID-19. But poor air quality is also linked to diabetes, heart disease and cancers. New research suggests air pollution may also affect the brain and be linked to developmental problems in babies.
Already, UNEP data indicates that air pollution has contributed to an estimated seven million premature deaths every year. In 2019, around four million people died from exposure to fine particulate outdoor pollution, with most deaths in East Asia and Central Europe.
4. Displacement and migration is putting people at risk
Climate change is leading to more frequent and severe extreme weather events such as intense heatwaves, wildfires and floods. These can not only cause humanitarian emergencies and a loss of life, but can also lead to displacement and migration, particularly in low-lying coastal areas and areas prone to extreme weather events.
Population movement can lead to a greater risk of infectious diseases due to overcrowding and poor sanitation. Many migrant populations have little or no access to healthcare, especially to geographically static health interventions such as routine immunisation or maternal health programmes, which means they miss out on essential healthcare, putting them at greater risk of disease.
5. Climate change is affecting mental health
Global warming is damaging our mental health in a myriad ways. Extreme weather events trigger population displacement that can cause increased stress and damage people's mental health as they are constantly on the hunt for resources such as food, water, shelter and access to healthcare. High temperatures, and especially heatwaves, have several negative effects on mental health such as a rise in depression and anxiety, and there is a proven link between rising temperatures and suicide attempts. Data indicates that for every 1°C increase in monthly average temperature, mental health-related deaths increase by 2.2%.
As the IPCC says, air pollution also affects our mental health, with depression and anxiety rising as air quality falls – in the US, short-term exposure to pollutants (PM2.5 and NO2) was associated with higher risk of acute hospital admission for psychiatric disorders. In the UK, higher levels of air pollution have been linked with a rise in use of mental health services for people living with psychotic or mood disorders.
