Climate Change and the Impact on Digestive Health

Written by: Dr. Desmond Leddin, Dr. Mary Zachos, Dr. Natasha Lepore, Kelsey Cheyne, CDHF

Updated: June 10th, 2026

This article aims to provide you with some information about climate change and its impact on your health. We want to inform you so that you can make choices regarding how you can protect yourself from it and how you can contribute to meeting the challenge. More of a visual learner? Skip to our infographic on climate change and the impact on digestive health.

Firstly, we need to sort out a bit of background and definitions:

Weather refers to the temperatures and cloudiness and rainfall which we experience day to day.

Climate change is when the usual weather in an area changes over a long time (like several decades). Sometimes people will say if it’s a hot day in the winter “So much for climate change”, but that’s wrong, climate is not the same as day-to-day weather, but weather pattern over a long time.

Let’s dive in!

What is climate change, pollution and biodiversity loss?

Climate change is happening because the earth’s atmosphere is changing. The atmosphere is a thin layer of gas that surrounds the planet; a bit like the skin on the outside of an apple.

For instance, when you fly in an airplane almost all the atmosphere is between you and the ground. The Earth receives its energy from the sun. Normally a significant amount of that energy is reflected into space. However, humans have been pouring chemicals, like greenhouse gasses, into the atmosphere for centuries and some of those hold energy back and prevent it from being lost into space. This has led to the atmosphere getting warmer and warmer as time goes by.

The energy present in the atmosphere increases the extremes of the weather events we experience. This means temperatures are more extreme; dry periods tend to be drier, rainfall can be heavier, resulting in flooding, hurricanes and storms that are more intense.

Greenhouse Gases

There are several greenhouse gases, and many occur naturally, but some are produced by human activity. The most common is carbon dioxide. The biggest source of it is from burning fossil fuels like gasoline, oil and coal.

Methane is another powerful greenhouse gas. It can occur naturally when plant material rots. Cattle also produce methane which is one reason why there are calls to reduce meat consumption. Natural gas, which is used as fuel, is methane and some of it is lost into the atmosphere when it is extracted from the ground.

Finally, there are other gases which are man-made such as the anaesthetics used in hospitals for surgery. Some medications like asthma inhalers also contain powerful synthetic greenhouse gases.

Pollution

We all tend to focus a bit on climate change since it’s the change in temperature and rainfall, and the shifting of seasons. However, the same things that cause climate change, such as burning fossil fuels and driving cars, also cause pollution.

Pollution is the introduction of harmful materials into the environment. It can occur naturally, but a lot of it is caused by humans. Pollution is emerging as a significant risk to human health(1).

Pollutants can interact with humans in several ways. They can be in the air that we breathe, or in the water that we drink or in the food that we eat.

Biodiversity

Another thing we need to consider is biodiversity. Biodiversity refers to the range of animals, plants and other living organisms on the planet. A rich and wide biodiversity is important for our health and for that of everything on the planet, including plants and animals.

Biodiversity is decreasing because of climate change and pollution. One example of biodiversity loss is that of pollution from pesticides killing bees. We need bees to pollinate plants so that we can grow food. Biodiversity is important in protecting us from disease and epidemics, it keeps our water clean and our food supply intact.

How do Climate Change, Pollution and Biodiversity Interact?

So, these three factors are related, climate change, pollution, and biodiversity loss. Let’s bundle them up and call them environmental change. Until recently the connections between environmental change and human health were not studied much.

However, more studies have been conducted in recent years, so let’s explore those preliminary results.

Connections between global warming, pollution, biodiversity loss and digestive health(14).

Why do I need to know about climate change and health?

Environmental changes can impact almost every aspect of human health, from conception to death. Every organ system in the body can be affected by these changes.

For example, recent evidence has linked maturity-onset diabetes with air pollution(2). No one has ever thought about that before, but now this theory is being actively investigated.

The reverse is also true. Healthcare delivery in Canada contributes over 4% of greenhouse gases to the atmosphere(3). So, we now know that trying to make people better actually makes some people sick because of the greenhouse gases, and pollution which we are releasing from delivery of care. That’s a bit of a problem and has led to a lot of activity in the healthcare sector to try and reduce the impact of healthcare delivery on the environment.

How does producing food contribute to climate change?

The food that we eat contributes to our health and can also affect the health of the planet.

For example, a diet high in red meat is linked to an increased risk of disease in humans such as certain types of cancer and heart disease. Red meat consumption also contributes to greenhouse gas emissions since cattle, from whom we get meat, produce significant amounts of methane, a powerful greenhouse gas. Further, runoff manure from cattle herds can destroy rivers and lakes. A diet based on vegetables, fruits, nuts, and minimal meat is beneficial for both human health and the environment.

Who is most vulnerable?

We are all vulnerable to the effects of climate change, pollution, and biodiversity loss. However, some groups are more vulnerable than others either because of their stage in life, underlying health issues or financial circumstances. This includes:

Lower socioeconomic groups
Children
Older adults
Pregnant individuals
Those with certain chronic diseases
Those with disabilities

Children

Children’s rapid growth and changing bodies, along with their exposure to risks over many years, make them more likely to be affected by things in the environment that can harm them. As temperatures rise around the world, there have been more severe weather events. These events put children’s safety at risk and make it difficult to access healthcare. Children are more vulnerable to high temperatures and are at greater risks of heatstroke, dehydration and harm to the respiratory and cardiac systems. Babies and young children are at higher risk from extreme weather because their temperature regulating systems are not fully developed. Heatwaves can also impact education as many classrooms in Canada are not temperature controlled which can make it difficult to concentrate and learn.

Air pollution directly impacts children’s health because they breath faster than adults, have immature lungs, and usually spend more time outdoors. When air quality worsens including smoke from wildfires, it leads to higher rates of emergency department visits for heart and lung issues, particularly asthma exacerbations.

Environmental change also has effects on digestive health in children. Changes in rainfall patterns can make water unsafe to drink, which can lead to diseases and poor nutrition. Events like floods and droughts disrupt how we grow food and its availability. Good nutrition is important in childhood to allow for children to grow and for brain development. Changes in the environment have increased the risks of infection from food and water sources and from insects and ticks. Young children are more likely than adults to have bacterial infections causing diarrhea(4) .

Although less well studied than these physical health concerns, climate change also impacts children’s mental well-being. Research has shown increased depression, post-traumatic stress disorder, and anxiety caused from events such as damage to homes, seeing caregivers undergo stressful relocations from extreme weather, interruptions in daily routines, and the uncertainty of the future(5) .

Lower Socioeconomic groups

People in lower socio-economic groups, generally have higher burdens of chronic illness. In addition, they may not have the financial or other resources to cope with climate challenges, like heat waves and storms. People with lower incomes may not be living in ideal conditions and may not have access to air conditioning when needed. Environment change can drive up food prices, especially of fresh fruits and vegetables. This may drive people towards more processed foods which are not as healthy.

Older Adults

Older adults are vulnerable to climate change for some of the same reasons as those in lower economic groups. They may have a higher burden of chronic illnesses like lung disease and diabetes. They may be more susceptible to dehydration. Limited mobility can make it difficult to deal with disruption to transportation which can occur with storms and other climate events

Pregnant Individuals

There are several links between climate change and pregnancy. Exposure to high temperatures may increase the risk of the baby being delivered too early. There is also some evidence that high temperatures can cause illness in the mother(6).

Individuals with Chronic Diseases

Climate change and pollution may be contributing to an increase in several chronic diseases. Leaving that aside however it is now clear that climate change and particularly high temperatures and pollution can make a lot of chronic diseases worse. For example, air pollution is linked to worsening lung problems like asthma and obstructive airways disease. Air pollution is also linked to an increased risk of heart attacks and stroke. Dehydration from high temperatures can worsen kidney disease. Virtually every organ system can be affected by the combination of climate change and pollution.

People with Disabilities

The effect of environment change can vary across a very wide variety of different types of disabilities. In general, however, climate change and pollution, tend to make life more difficult for people who may already be challenged in various ways. Extreme weather can limit mobility and the ability to get around. Sometimes supplies can become strained and it may be difficult to get the medication and care which people need.

How Does Climate Change Impact those with Digestive Health Diseases?

A lot of attention has focussed on the health connections between environmental change and disease of the lungs and heart. However, it’s now clear that the intestine is also impacted(7). Specifically, increasing temperatures may lead to intestine dysfunction.

There is a particular type of pollution called particulate matter in the air. Particulate matter (PM) refers to very fine particles of dust. They are measured in millionths of a meter. These particles are small enough so that you can breathe them in, and they go down into the depths of the lungs and transfer over into the bloodstream. They are then moved all around the body. They can also reach the intestine by being swallowed from food or when they stick to your throat when you breathe. These particles can carry chemicals and they are appearing as a real concern regarding digestive health.

Plastic pollution is now widespread, and it has also been linked to digestive disease.

Particulate matter pollution and plastics(8) have been linked to the potential risk of developing or exacerbating certain chronic diseases like:

Increased flare-ups in those with inflammatory bowel disease (IBD)
Liver diseases

Evidence is still emerging, but research on particulate matter and plastic pollution and the link to chronic disease is growing.

Climate change is a threat to our food supply and there is some evidence that it is moving people towards more processed foods. Food insecurity may lead to an increase in processed food consumption and increased processed food intake is linked to a greater risk of developing Crohn’s disease.

The news that we hear and the pictures that we see about climate change can affect our mental health and general well-being; with anxiety linked to certain functional gut disorders like irritable bowel syndrome (IBS).

Access to care may be affected by extreme weather since wildfires and storms and flooding can close down health facilities and disrupt delivery of care such as clinics and endoscopy.

Flooding is a particular concern(9). Municipal wastewater systems are built to deal with average conditions. The torrential rains associated with climate change can overwhelm the ability of municipal systems to treat water and infections can get into the drinking supply. This has already been reported in Canada(10).

Wildfires are now a feature of the Canadian climate. They contribute huge amount of pollution and cause biodiversity loss. There is a lot of concern that chemicals released in controlling wildfires, or by the burning, may affect water supplies but research in this area is still in early stages(11).

Despite all of this, Canada is still in a pretty good place when it comes to dealing with the upcoming threat of environmental change. That means that we will be a haven for people from many countries around the world who are worse affected. We need to plan for this by putting in place healthcare, housing, and support for migrants moving to this country. Otherwise, life and health of those already here will be negatively affected.

What can I do about it?

The question then is what can you do about it? One approach is to increase your ability to withstand the challenges of environmental change.

For example, we know that hurricanes will become more severe, and they may increase in number. If you’re living on the East Coast of Canada, it makes sense to take that into account, and prepare your home and supplies for the storm season.

Similarly, if you live in an area which may be affected by wildfires, you need to plan for it. Periods of intense heat will become more common, and we need to protect children and the elderly from it. That means making sure that there is sufficient access to areas of cooling and water supplies.

We need to build resilience in the healthcare system so that climate challenges don’t shut it down.

The other approach you can take is to try and reduce your contribution to the problem. That means reducing your greenhouse gas output, or what’s called your carbon footprint. There are several ways that you can do that. The first is trying to move away from fossil fuels (oil and gas) as much as you can. If you can afford it, solar panels ,or hybrid cars, or electric cars, or just using public transport are good ways to reduce the emissions that you are responsible for.

Moreover, changing your diet to one that has more vegetables and fruits is good for you and good for the environment(12).

Further, fast fashion is a significant contributor to pollution and water usage around the world. Consider buying less stuff or buying second-hand clothes.

Travel is one of the causes of pollution of the atmosphere, and you might consider reducing your air travel footprint.

Regarding healthcare, don’t get unnecessary tests or investigations, see if your doctor will provide follow-up visits by telemedicine, don’t waste medications and dispose of them at your local pharmacy.

There are signs of progress.

Now you know something about what’s happening in this area. The news isn’t all bad. In countries like Canada, carbon dioxide emissions per person have been falling for years(13). The world may have reached peak per person carbon emissions. There is a significant change under way. There is still time to tackle this issue. We can do that and make sure that the future is secure for our children and grandchildren. Healthy humans need a healthy planet, it’s in our interest to act.

climate change and the impact on digestive health infographic

Download the Climate Change & Impact on DIgestive Health Infographic

References

1. Fuller R, Landrigan PJ, Balakrishnan K, Bathan G, Bose-O’Reilly S, Brauer M, et al. Pollution and health: a progress update. Lancet Planet Health. 2022;6(6):e535-e47.

2. Burkart K, Causey K, Cohen AJ, Wozniak SS, Salvi DD, Abbafati C, et al. Estimates, trends, and drivers of the global burden of type 2 diabetes attributable to air pollution: an analysis of data from the Global Burden of Disease Study 2019. The Lancet Planetary Health. 2022;6(7):e586-e600.

3. Eckelman MJ, Sherman JD, MacNeill AJ. Life cycle environmental emissions and health damages from the Canadian healthcare system: An economic-environmental-epidemiological analysis. PLoS Med. 2018;15(7):e1002623.

4. Sockett PN, Rodgers FG. Enteric and foodborne disease in children: A review of the influence of food- and environment-related risk factors. Paediatr Child Health. 2001;6(4):203-9.

5. Helldén D, Andersson C, Nilsson M, Ebi KL, Friberg P, Alfvén T. Climate change and child health: a scoping review and an expanded conceptual framework. Lancet Planet Health. 2021;5(3):e164-e75.

6. Jiao A, Sun Y, Avila C, Chiu V, Slezak J, Sacks DA, et al. Analysis of Heat Exposure During Pregnancy and Severe Maternal Morbidity. JAMA Network Open. 2023;6(9):e2332780-e.

7. Donnelly MC, Talley NJ. Effects of climate change on digestive health and preventative measures. Gut. 2023;72(12):2199-201.

8. Yan Z, Liu Y, Zhang T, Zhang F, Ren H, Zhang Y. Analysis of Microplastics in Human Feces Reveals a Correlation between Fecal Microplastics and Inflammatory Bowel Disease Status. Environmental Science & Technology. 2022;56(1):414-21.

9. Carignan A, Valiquette L, Laupland KB. Impact of climate change on emerging infectious diseases: Implications for Canada. J Assoc Med Microbiol Infect Dis Can. 2019;4(2):55-9.

10. Chhetri BK, Takaro TK, Balshaw R, Otterstatter M, Mak S, Lem M, et al. Associations between extreme precipitation and acute gastro-intestinal illness due to cryptosporidiosis and giardiasis in an urban Canadian drinking water system (1997–2009). Journal of Water and Health. 2017;15(6):898-907.

11. Fadadu RP, Solomon G, Balmes JR. Wildfires and Human Health. JAMA. 2024.

12. Farvid MS, Sidahmed E, Spence ND, Mante Angua K, Rosner BA, Barnett JB. Consumption of red meat and processed meat and cancer incidence: a systematic review and meta-analysis of prospective studies. Eur J Epidemiol. 2021;36(9):937-51.

13. Per capita CO2 emissions. 2024 [Available from: https://ourworldindata.org/grapher/co-emissions-per-capita?tab=chart&country=~CAN.

14. Leddin D. The impact of climate change, pollution and biodiversity loss on digestive health and disease. Gastro Hep Advances. 2024.