How climate change is threatening human health

By Rhiannon Wardle

When you think about climate change, what’s the first thing you think about? For most people, their first thought is the destruction of the environment. This includes things like melting ice caps and deforestation. While this is a huge impact of climate change, the effects of global warming on human health are not to be ignored.

That’s why, in the midst of COP27, we’re focusing on human health and disease, to highlight just how far-reaching and detrimental climate change can be. It’s not just about saving the trees but about prolonging the lives of humans and animals. 

Between 2030 and 2050, the World Health Organisation expects climate change to cause 250,000 deaths per year as a result of heat stress, diarrhoea, malaria and childhood malnutrition.  

In this article, we’ll explore the consequences of climate change and delve into the biggest human health risks that come as a result. We’ll then discuss who is affected by climate change globally, and ask how we can minimise the impact of climate change on our health.

What are some of the biggest consequences of climate change?

In our article on climate change, we go into detail about the causes and consequences of climate change. But we’ll condense this down here to give you some context for the rest of the article. 

Fundamentally, climate change is the long-term shift in the regular weather conditions and temperature of a certain region. Yet, we usually talk about it on a global scale. 

Climates around the world aren’t all being affected in the same way, but we are seeing huge shifts in climate patterns across the whole globe. Our biggest concern is global warming – the earth is heating up every year.

There are four consequences of climate change that we detailed in our previous blog post, but many more negative outcomes follow as a result of these changes. They are extreme weather, mass extinctions, melting ice glaciers and changing wildlife habitats.

Each of these negative consequences has an impact on human health further down the line, and this is what we’ll be investigating today. 

What are the effects of climate change on human health?

There are numerous health risks that stem from issues related to climate change, but today we’re going to talk about some of the most impactful. It’s worth pointing out that these health risks are not caused by climate change alone, but there’s no denying the overwhelming impact it is having. 

You can learn more about the connection between climate change and human lives in our One Health: Connecting Humans, Animals and the Environment course by the University of Basel.

1. Lack of clean air

The reduction in air quality in many areas of the world is having a detrimental effect on people’s health in numerous ways. There are several main causes of air pollution related to climate change. These include increased ground-level ozone (smog) and more wildfires occurring.

Smog is created when sunlight, warm air and pollution from fossil fuels combine together and often can be witnessed as a thick haze in the sky. It can normally be found in big cities or industrial areas. 

This is due to the higher amount of fossil fuels burnt or more products with volatile organic compounds (VOC), such as paint and gasoline, being used. It’s also worth noting that burning fossil fuels releases air pollutants that can worsen allergies.

In addition, wildfires reduce air quality by increasing the amount of smoke in the air, and we’ve certainly seen an increase in wildfires lately. For example, the European Forest Fire Information System said that 175,000 acres were burned last year in Turkey. This is eight times more than the national average.

Decreased air quality can have negative impacts on health. Some examples include diminished lung function, an irritated respiratory system, aggravated asthma and an inflamed lung lining. 

While these can be short-term effects, living in air pollution for a long time can lead to long-term respiratory and lung issues.

2. Food shortages

It’s not surprising that climate change has such a negative impact on food supply. The growth of food in many countries is reliant on things like the weather, temperature, soil quality and spread of disease.

In our open step, Poverty, inequality and food insecurity by the University of Bergen, we discuss the ways in which food security is affected by climate change. 

They suggest that food access, utilisation and price stability are all affected by climate change. One of the key issues is changes in the distribution of weeds, agricultural pests and diseases. 

Additionally, temperature increases can have a negative impact on yields for crops such as rice and wheat. Changing aquatic ecosystems are also affecting fish in freshwater and saltwater areas.

While a lack of essential, filling crops such as rice and wheat can be devastating for many communities, one billion people are also reliant on fish as their primary protein source. This means that many people are suffering from hunger and poor nutrition.

If we don’t seek to correct these issues, by 2050, we could see an increase in malnourished children under the age of five by 20-25 million. This is a scarily large number. Ensuring that children receive a nutritious diet is important for disease prevention, physical strength and cognitive development.

3. Spread of disease

A very concerning side effect of climate change on human health is the increased spread of diseases. In our Vector-borne disease open step, the University of Bergen explains how diseases such as malaria, dengue fever, and Japanese encephalitis are “climate-sensitive”.

This is because new habitats for disease-spreading insects are created as a result of changing temperatures and rainfall patterns.

While climate change isn’t always the prevailing factor in these diseases being spread, there are examples where it’s become a big concern. For example, dengue fever has been closely linked to climate change, since it’s increased 30-fold over the past five decades.

On the subject of water-borne diseases, climate change has certainly had a negative impact on their spread too. In our Climate Change and its Impact on Water Health open step, EIT Food talks about how increased flooding and precipitation means that more animal waste, pesticides, fertilisers and water-borne diseases are able to enter waterways and food systems.

For example, more surface water and increased nutrients from agricultural runoff can lead to harmful algal blooms in the sea. These can release biotoxins. If humans eat contaminated fish or shellfish, they could be subject to neurological damage, respiratory harm and diarrhoea. These are just a few potential health consequences.

You can learn more about the spread of human diseases in one of our courses by the University of Leeds. For example, in our Causes of Human Disease: Nutrition and Environment course, you can explore how nutrition and environmental factors such as toxins influence your chance of developing human disease. 

4. Droughts and heatwaves

We’ve already spoken a little bit about wildfires, but what exactly is causing them? Most of the time, they happen during a heatwave, and often because the trees are very dry due to a lack of precipitation. This brings us to the next big issue for human health caused by climate change: droughts and heatwaves.

Both droughts and heatwaves have direct and indirect health effects. Heat itself can make people very ill, especially the elderly, infants, pregnant women and sick people. Not to mention, those who have to work outside all day in order to make a living. 

This could become even more of a problem in the future, as discussed in our open step, Heatwaves, drought and wildfires, by the University of Bergen. 

They discuss how a study in Australia estimates that the number of dangerously hot days per year will rise from the current 4-6 days to 33-45 days by the year 2070. They also mention how extreme heat can prevent health, emergency, and social services from providing proper care. 

A side effect of droughts and extreme heat, alongside wildfires, is water scarcity. Certain regions will experience less precipitation than usual, and this can mean people and animals suffer from a lack of drinking water and a higher concentration of contaminants in water sources.

5. Natural disasters

In our Storms and floods open step, the University of Bergen discusses how the number of weather-related natural disasters globally has more than tripled since the 1960s. Each year, these events result in over 60,000 deaths.

It might appear that the main issue with natural disasters is that they destroy properties and natural habitats. But they also can be disastrous for human health issues. For example, flooding contaminates freshwater supplies, which increases the risk of water-borne diseases. It also increases the rate of reproduction for disease-carrying pests like mosquitoes.

Take the recent devastating floods in Pakistan, for instance. Torrential monsoon rains led to the worst flooding experienced in many years, and almost 10 million children have needed crucial support to protect them from waterborne diseases, malnutrition and homelessness.

Many natural disasters are also a direct health concern and put people in danger straight away. Floods and tsunamis can cause drowning, while earthquakes and hurricanes can cause physical injuries and disabilities. What’s more, natural disasters can put a huge strain on healthcare delivery because of the sudden, widespread disorder and damage.

Who is most affected by climate change globally?

It’s important to recognise that not everyone is affected by health issues related to climate change equally. In our poverty and climate change open step by the University of Nottingham, experts suggest that those who live in poverty are more likely to struggle with climate change-related health issues. The main reason for this is inadequate resources. 

Not having the right resources renders people living in poverty more vulnerable. This is because they are less able to adapt to risks, cope with risks, and are more likely to experience harm.

They will likely be less able to deal with infrastructure damage as a result of natural disasters, the spread of disease due to flooding and food shortages due to lack of precipitation. Not to mention, poorer communities will have less access to effective healthcare services.

Our open step on poverty, inequality and food insecurity by the University of Bergen also points out that climate-related issues such as water scarcity and food shortages can be the tipping points for some low-income families to fall into true poverty.

It’s not just wealth that affects susceptibility to climate change-related health risks – climate trends vary greatly depending on the region. 

This means that those who live in floodplains are more likely to experience health risks related to flooding. Similarly, those who live in regions with poor air quality are more likely to experience respiratory or lung diseases. 

How can we address climate change and health?

So what are some of the things we can do to lessen the negative health effects of climate change? The main thing is to try and stop global warming altogether. We go into more detail about this in our how to save the planet and how to live sustainably articles. 

We also offer inspiring climate change courses and sustainability courses. For example, you might like our Planet Partners: Tackling the Climate Crisis Together course. 

However, we’ve also provided some more specific examples of what you can do to help below, both as an individual or as a government or corporation:

What can I do as an individual?

• Write to your MP to encourage climate-positive and anti-fossil fuel legislation
• Stay indoors when there is smog/air pollution
• Reduce your consumption of greenhouse gases
• Protect yourself from mosquito and tick bites
• Get involved in a climate action group
• Lower your carbon footprint
• Protect yourself from the sun by using SPF and finding shade
• Buy from local stores when you can
• Volunteer if you have free time
• Donate to local charities when there are natural disasters or food shortages.

What can governments and corporations do?

• Support local food providers and sustainable food practices
• Reduce (and preferably, eradicate) the amount of fossil fuels burned per year
• Design more sustainable and energy-efficient buildings
• Invest in green energy providers
• Take action to prevent food waste
• Improve climate education in schools
• Invest in and support healthcare providers.

Final thoughts

Even if you don’t feel like you’re affected by these climate-related issues, it’s important to understand how your actions can have repercussions on the health of others.

Equally, your actions could help people who suffer from climate change-related health issues. For example, switching to green energy is a good option to save money and reduce your carbon footprint. Yet, it can have many more far-reaching positive consequences.