Climate Action

Addressing climate change is one of the best ways to improve public health

Climate change is one of the greatest threats to public health globally. Medical providers across the world are seeing the consequences of warming — from the spread of infectious diseases to increased cardiovascular stress. As global warming continues, these health consequences will continue to grow unless aggressive international climate policy is made that effectively addresses greenhouse gas emissions.

There is overwhelming consensus that the health of those of a lower socioeconomic status and those living in less developed countries will suffer the most from global warming, while those same populations contribute the least to global emissions. The continent of Africa, for example, represents approximately 2-3% of global greenhouse gas emissions. Yet people living there are increasingly threatened by health concerns including food and water insecurity due to drought and flooding, as well as new diseases, such as Dengue, emerging in regions previously not present.

It is essential that we understand how climate change impacts health, as well as prepare for what is to come in the absence of effective climate mitigation. Here are five ways climate change is impacting health on a daily basis.

Spread of infectious diseases

Global warming alters temperature and rainfall patterns, contributing to a change in the activity of some vector-borne diseases. For example, heat and drought conditions are causing larger bodies of water to become smaller and more static, creating a perfect breeding ground for mosquitos, the main vector of West Nile virus. There has also been a rise in the incidence of Dengue in recent decades, which is in part due to changes in precipitation and temperature.

Like mosquitos, hotter conditions alter the range of habitat for ticks, resulting in a northward expansion of Lyme disease in the United States and into Canada.

Worsening of seasonal allergies

For those with seasonal pollen allergies, climate change is leading to longer allergy seasons, as well as a worsening of allergy symptoms. Because of global warming, the freeze-free season is gradually extending. 

This means that plants and trees that produce pollen are able to grow for a longer period of time during the year. On average, in North America, this length of time has extended by about 20 days as compared to 30 years ago. 

In addition, higher levels of carbon dioxide in the atmosphere are leading to increased plant growth, which has also caused an increase in pollen production. There is an approximate 21% increase in pollen levels today as compared to 30 years ago.

Mental health

The mental health consequences of global warming range from greater risk of aggressive behavior, to higher rates of post-traumatic stress disorder, to increased rates of suicidal tendencies. Research has shown people exhibit higher levels of irritability, aggression and even violent behavior when exposed to extreme heat, which is becoming increasingly likely due to global warming. Record temperatures in the Western United States are among the latest occurrences of extreme heat. With each °C of global temperature increase, days of extreme heat are projected to increase between 4-34 extra days per season.

In addition, across the globe, climate change is leading to intensified natural disasters, from hurricanes to wildfires. These intensified natural disasters contribute to widespread devastation and loss of homes. In the wake of this destruction, people are exhibiting growing levels of trauma and shock, which can lead to post-traumatic stress disorder.

Greater risk of heart disease and heart attacks

The last decade was the hottest one on record. This causes thermal stress on the body, leading to physiologic changes, including increased sweating and higher heart rate, as well as higher blood pressure and systemic inflammation. 

These changes can lead to an increased risk of heart disease, as well as complications such as heart attacks and strokes. Many of these heart complications are of highest concern in the most vulnerable people, including those who are elderly, those of a lower socioeconomic status and those who already have other health conditions, such as diabetes.

Increased risk of kidney disease

Working outside during the increasingly hot summers is a major health concern, with increased risk of illness and death due to dehydration and heat-related illness. One of the organs most susceptible to the impacts of heat is the kidneys, where prolonged heat exposure can lead to higher incidence of kidney stones, as well as development of chronic kidney disease.

These health consequences also carry a major economic burden, with outside laborers such as agricultural and construction workers across the globe being unable to work outside during heat waves, with a potential 302 billion work hours lost in 2019.


Each of these health impacts demonstrates that global warming fundamentally alters how our bodies function, putting our health and safety at risk. Climate change should be viewed as a public health crisis, just as it is viewed as an environmental one.

There are many ways to get involved and be part of the solution to protect public health. Organize a teach-in to educate your community about the effects of climate change on health, participate in a cleanup to keep your environment clean from plastic and check out the Earth Day Action Toolkit for more ideas.

A healthy planet is not an option — it is a necessity. We must Restore Our Earth not only to protect the world’s ecosystems, but also to ensure our health and survival.