The climate crisis is taking the world over. It has repercussions in a variety of areas, and one is human health, including the heart and the lungs.
Climate Change vs. Heart and Lung Health: The Causes and Effects (Part 1)

We need a healthy heart as well as lungs to live a happy life. The cardiovascular system consists of the heart, arteries, veins, and capillaries. The heart pumps the blood through the circulatory system by rhythmic contraction and dilation. The respiratory system is the network of organs (including lungs) and tissues that help you breathe. So, the two systems of our body, i.e., the cardiovascular and the respiratory, should function well if we want to lead a happy life.

Climate change has an impact on our health. Major sources of greenhouse gas emissions that cause climate change include fossil fuel burning, agriculture, and deforestation. Climate change leads to more frequent extreme weather events (such as heatwaves, wildfires), air pollution, ecosystem collapse, and declines in the global food production and the nutritional quality of major cereal crops. Globally, the healthcare sector is responsible for nearly 5% of emissions. If the healthcare sector were a country, it would be the fifth largest polluter in the world. Moreover, the healthcare sector accounts for nearly 3% of fine particulate matter air pollution (PM2.5).

As a result, the climate change makes the heart and lungs go weaker, causing heatwaves, wildfires and bushfires, air pollution, allergens, and flooding and other extreme weather events. Climate change also can affect food, power, and water supply and quality, impacting migratory patterns of both humans and vector‐borne diseases. Moreover, people with existing heart and lung conditions have an increased risk of complications.

For example, elevated temperatures were responsible for an estimated 93,000 cardiovascular deaths around the world in 2019 alone. The extreme weather events that occur due to climate change are linked to trauma, stress, and depression, which are risk factors for coronary heart disease. Moreover, desertification, increased atmospheric carbon dioxide, and ocean warming and acidification affect nutritious food supplies. So, diets low in fresh produce, whole grains, and seafood are responsible for over 3 million cardiovascular deaths annually worldwide.

In the open-access journal BMJ Global Health, focusing on the heart, a new speciality called climate cardiology is identified to tackle links between climate change and cardiovascular health, protecting patients and the future of the planet.

The causes and effects of climate change

Climate change affects the heart and lung health through heatwaves, wildfires and bushfires, air pollution and allergens, and other extreme weather events, including flooding.


The three hottest years in the world are 2015, 2019 and 2020 and the air temperature in increasing in 2023. A heatwave is defined as unusually high air temperature that would last three days in a row. With elevated temperatures, heatwaves become more frequent in the world. Prolonged high air temperatures and heatwaves will cause drought.

High air temperatures during a heatwave or even single hot days cause health risks, both directly and indirectly increasing cardiovascular and respiratory morbidity and mortality (or diseases and death).

Heatwaves can be dangerous for people with existing health conditions, including heart and lung conditions. For example, acute cardiovascular disease or (CVD) such as myocardial infarction is at an elevated risk of heart problems. CVD events are the primary cause of death during heatwaves. Older people as well as people experiencing socioeconomic disadvantage are also at higher risk during a heatwave.

Hot temperatures have a spiralling effect as they lead to increasing levels of ground‐level ozone, a greater risk of wildfire and dust storms, and a higher demand for electricity, which in turn increases demand for fossil fuel combustion and air pollution.

Wildfires and bushfires

When air temperature becomes too high for a period, perhaps causing drought, it leads to wildfires and bushfires. Now that air is hotter than usual, wildfires and bushfires are becoming more widespread and severe due to climate change. They are also a common source of air pollution.

Smoke exposure from wildfires and bushfires can put increased stress on the heart and can be dangerous for people with heart conditions (such as heart failure and high blood pressure) and older people.

Bushfire smoke can contain harmful gases (carbon monoxide) and toxins. Bushfire smoke also creates tiny solid particles and airborne liquid droplets that you cannot see. This is called ‘particulate matter (PM)’. These small particles can cross the lungs into the bloodstream. Being exposed to such smoke might also increase the risk of cardiac arrest or heart attacks.

The exposure to it can cause symptoms including chest pain or tightness; irritation of eye, nose, and throat; difficulty breathing, shortness of breath, coughing or wheezing; racing heart or palpitations; and tiredness. Further, microscopic particles found in wildfire smoke cause everything from coughing and asthma flare-ups to heart attacks and premature death, especially for those with heart and lung diseases.

Wildfires and bushfires blow smoke hundreds of miles away, so it is not just people who live in wildfire-prone regions who are at risk but people living in cities can be exposed.

Like extreme weather, wildfires and bushfires can force people to evacuate, which can make it hard to access medical care.

Air pollution and allergens

Air pollution is the world’s single largest environmental health risk. Climate change increases the risk that air pollution, including ground-level ozone and particle pollution, will worsen. Climate change creates conditions, including heat and stagnant air, which increase the risk of unhealthful ozone levels. Ground-level ozone, often called smog, forms in the atmosphere when gases emitted from sources like smokestacks and tailpipes mix in the air. Hotter weather and stagnant air create conditions that make ozone more likely to form.

Long-term exposure to air pollution can increase the risk of cardiovascular disease, including heart attack, coronary heart disease, abnormal heart rhythms, cardiac arrest, heart failure and stroke. Globally, air pollution from fossil fuel burning, industrial emissions, and landscape fires are responsible for nearly 1 in 5 cardiovascular deaths.

Air pollution refers to the small particles and gases that circulate in the air. When people inhale these particles and gases, they can harm the heart and lungs. Air pollution can occur in both outdoor and indoor environments.

If humans breathe in very small air pollution particles, this can affect the heart by: damaging blood vessels so they become hard and narrow; increasing the risk of blood clots; increasing blood pressure; disrupting the electrical activity of the heart, which can lead to abnormal heart rhythms; and changing the structure of the heart (in a similar way to what happens in early heart failure).

Hotter temperatures and the lack of rainfall also increase the risk of drought and wildfires, both of which create particle pollution. Wildfires have become a major source of extremely high particle levels in places hundreds of miles from fire sites. Dust storms also contribute to particle pollution, and they are expected to increase as soil dries out and the water table drops.

Air pollution gets worse as temperatures rise, stressing both the heart and lungs. The fossil fuel pollution that causes the climate crisis is linked with increased hospitalizations and deaths from cardiovascular disease, and it relates to more asthma attacks and other breathing problems.

For allergy sufferers, climate change may mean more itching and sneezing. As temperatures rise, plants produce more pollen, increasing ragweed and other allergens. Moisture from increased rainfall and floods can raise the risk of mould. Warmer temperatures also allow allergens to flourish in new regions and for allergy seasons to last longer.

Other extreme weather events, including flooding

Climate change increases the risk of flooding and other extreme weather events, such as famine, storms, drought, and sea level rise, which can damage homes, businesses and infrastructure, sometimes resulting power outages. Such events are associated with an increased risk of hospitalization for cardiovascular disease.

When forcing families to evacuate their homes, they have little time to recover essential medicines or seek medical care elsewhere. Those who return often face homes with mould, polluted floodwater residue and other damage, exposing them to indoor air pollution as they clean up and repair their dwellings. Some would forcefully migrate, often to places ill prepared to provide health services of the heart and lungs.

These changes in climate also impact agricultural production, food security, and political stability, particularly among vulnerable communities and regions.

The solutions?

If we sadly continue to emit carbon emissions which contributes to climate change, the 1.5C threshold would last this decade, i.e., only until 2029. So, we must act now.

There are solutions to maintain the human health of the heart and lungs, especially if you have cardiovascular or respiratory conditions, in climate change. The next post will bring that.


Note: This article was first published in The Sustain blog on 31 October 2023:


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