What you need to know

  • Climate change impacts health in many ways, including by making weather more extreme and creating better conditions for disease-carrying organisms.
  • The health effects of climate change can harm everything from our heart and immune system to our mental health and ability to sleep. 
  • Vulnerable and marginalized communities, like older adults and low-income populations, are at the highest risk of climate-related health effects.

Our environment influences our health—especially the climate. Climate change fuels extreme temperatures, severe weather, poor air and water quality, and carriers of infectious diseases, all of which have negative impacts on our overall health.

Here are some of the many ways that climate change is making us sick. 

Cardiovascular health

The cardiovascular system includes your heart and the blood vessels that carry blood (and oxygen) to every part of your body. Decades of research have shown that certain climate-related “stressors,” such as heatwaves and tropical storms, are bad for cardiovascular health.

A 2024 review of nearly 500 studies published between 1970 and 2023 found that climate hazards are associated with an increase in cardiovascular events, like heart attacks and strokes. The article emphasized that older adults, low-income communities, and racial and ethnic minorities are particularly vulnerable to these climate-related health effects.

Meanwhile, a 2023 study projected that cardiovascular deaths from extreme heat in the U.S. are on track to increase dramatically by the middle of the century.

“In the United States, an estimated 1,600 deaths due to cardiovascular disease

occurred annually [from 2008 to 2019] due to extreme heat exposure,” said Dr. Sameed Khatana, a cardiologist at Penn Medicine and the study’s lead author, in a University of Pennsylvania video. 

Khatana found that the number of deaths could double or even triple in the coming decades if greenhouse gas emissions increase.

Mental health

In 2022, the World Health Organization published a brief concluding that climate change “can lead to emotional distress, the development of new mental health conditions and a worsening situation for people already living with these conditions.” 

Many people experience stress and anxiety about the global climate crisis. A May American Psychiatric Association poll revealed that more than half of adults in the U.S. report climate anxiety, a persistent fear or stress about the climate. This anxiety is often worse for individuals with existing mental health conditions, about one in five U.S. adults.

The mental health impact is even greater for people who have survived extreme climate events, which are increasingly common.

“After [Hurricane] Katrina, we saw…rises in conditions like trauma-related disorders, anxiety, or depression,” said Dr. Jacob Lee, a psychiatrist and the chair of APA’s Committee on Climate Change and Mental Health, in an August interview.

He added, “That’s kind of a pattern we see across a variety of other disasters that are becoming more frequent.”

Additionally, people with existing mental health conditions are especially vulnerable to extreme heat, which can worsen symptoms. Difficulty regulating body heat is also a side effect of certain anti-psychotic and anti-depressant medications, making people taking them more susceptible to heat exhaustion and heat stroke. 

Immune disease

Climate change also takes a toll on the immune system, our body’s primary defense against disease. A 2024 review reported that climate stressors can damage the immune system. This leads to an increase in immune conditions, including allergies, asthma, and autoimmune diseases, which occur when the immune system mistakenly attacks healthy cells. 

“Climate change derails the human immune system in two [key] ways: it breaks down the body’s defenses and also prevents the body from rebuilding them,” wrote Dr. Kari Nadeau, one of the study’s authors and professor of climate and population studies at Harvard University, in a STAT News opinion piece.

“All these exposures damage the structures that have evolved to protect humans from infection, including the skin and the mucous membranes of the gut and lungs.”

Similarly, a 2023 report suggests that a climate-related rise in pollutants, allergens, and disease-carrying organisms could lead to allergic and autoimmune conditions. Like previous studies, the paper emphasized that lower-income and marginalized communities “bear a disproportionate burden of climate change.”

Sleep 

Sleep is one of the most important—and most frequently neglected—components of health. Consistently getting enough sleep is linked to better overall health and lower risks of a host of chronic diseases. Unfortunately, climate change is also diminishing our ability to get a good night’s sleep.

A June study found that warming temperatures increased rates of sleep apnea, a condition in which breathing pauses during sleep. The condition, which affects around 1 billion people worldwide, can lead to poor sleep quality, chronic sleepiness, and headaches during waking hours. 

“If temperature keeps rising the way they project it to, the burden and prevalence of sleep apnea may double,” said Bastien Lechat, the study’s lead author and a senior research fellow at Flinders University in Australia, in an ABC News interview.

An earlier study projected that rising global temperatures could result in people losing up to 58 hours—seven to eight nights—of sleep per year by the end of the century. The researchers emphasized that women, older adults, and individuals living in lower-income countries are most affected by climate-related sleep loss. 

Infectious disease

Climate change also creates ideal environments for organisms that cause and carry human diseases. Research suggests that climate change is accelerating the spread of a staggering number of infectious diseases. 

Disease vectors like mosquitoes and ticks carry harmful viruses and bacteria that they pass to humans. Warming temperatures and changes in precipitation patterns have allowed these organisms to expand their population and spread to new areas. For example, in recent years, mosquitoes carrying dengue and other deadly viruses have spread to previously unaffected regions. 

Similarly, this year the U.S. has seen an “explosive increase” of ticks, including a species that triggers a severe allergic reaction. Historically, these ticks were primarily found in warm climates such as the southeastern United States. Now, they’re increasingly spreading to northern regions as rising temperatures allow them to thrive in places once too cold for their survival.

“The reality is that with the changes we’re seeing in climate, we have to be more prepared and more aware of the infections and the pathogens that we can be exposed to by being outside,” Dr. Manisha Juthani, the Connecticut Department of Public Health commissioner, told NBC News.