Dr. DeJarnett explains how climate change threatens public health


By Sara Wanous

Each month, Citizens’ Climate Lobby hosts an online meeting featuring a guest speaker to educate listeners on topics related to climate change, carbon fee and dividend, and the Energy Innovation and Carbon Dividend Act. Check out recaps of past speakers here.

Climate change is a large-scale threat, but it is also as personal as our own health. Dr. Natasha DeJarnett of the National Environmental Health Association (NEHA) investigates how climate change and environmental exposures affect public health.  She is among many health professionals paying attention to the effects of climate change on health. According to Dr. DeJarnett, “Many of the health organizations, especially their leadership, all stand by and say that climate change is the greatest threat to public health that we are currently facing.”

Dr. DeJarnett consistently shares her knowledge and experience with our organization by sitting on Citizens’ Climate Education governing board, speaking at our conferences, and most recently joining our national call this February. She covered three major areas—air quality, water quality, and mental health—as well as the importance of communicating how climate change impacts health.


The quality of the air we breathe is vital to our health. The Harvard Six City study dramatically showed that cities with higher pollution had higher mortality rates, and further studies have linked worse air pollution with shorter life expectancies. Anthropogenic climate change warms our atmosphere, trapping both heat and pollution. Dr. DeJarnett said it simply: “Climate change is harming our health. It’s threatening our lives, and it’s also shortening our lives.”

The increased heat associated with climate has negative health effects, too.  Longer, hotter warm seasons caused by climate change lead to more pollen. Increased pollen counts exacerbate common allergies, which leads to decreased workplace productivity and an increase in school absences. These longer, hotter warm seasons also increase the range of vectors. Vectors are small organisms that carry diseases, like ticks carrying Lyme disease and mosquitos carrying West Nile. Climate change increases the range of viable habitat for these animals and increases the population as fewer die off in the shorter cold seasons.  

Under these air quality hazards, Dr. DeJarnett said, “We’re all at risk.” But she pointed out, “There are some of of us who are more vulnerable—children in particular.” According to the World Health Organization, 88% of the burden of climate change falls on children.


Increased atmospheric heat associated with climate change causes instability in our atmosphere, which increases the frequency and intensity of extreme weather events. This means that climate change brings us more varied precipitation, causing both more flooding and more droughts.

Flooding is a risk Dr. DeJarnett has encountered personally. “My family and I were in a flood situation,” she said. “There was a flash flood incident—the road completely flooded—and we found ourselves at a point where we couldn’t see the street anymore. Unfortunately we proceeded, which is not what you’re supposed to do if you don’t see any street lights.” Thankfully they made it through, but it was a frightening situation and one that will happen more and more in years to come as climate change advances.

Beyond direct injuries and drownings, flooding increases the spread of diseases. Floods often overflow sewer systems, mixing raw sewage with fresh drinking water systems. A Johns Hopkins study showed that over half of gastrointestinal illness outbreaks were preceded by an extreme rainfall event.


Dr. DeJarnett emphasized the importance of considering the mental health effects of climate change alongside the physical health effects. Though research of the physical effects is more developed, the growing pool of research on the mental health effects of climate change related events has shown alarming results.

Dr. DeJarnett cited studies showing that “49% of Hurricane Katrina survivors were left with some type of anxiety or mood disorder following the storm,” and “1 in 6 Hurricane Katrina survivors developed PTSD after the storm.”

Extreme heat also creates unique issues. When temperatures soar high enough, some medications meant to treat mental illness no longer work. People with close cultural or economic ties to the land are at risk too. During a recent midwest drought, the suicide rate in farmers doubled.

Communicating the connection

According to Dr. DeJarnett, “Bringing health into the climate conversation is one of the most important things that we can do.” Health is both a universal and personal experience. The health impacts of climate change are important to every single community and can be conveyed through individual, but relatable, stories.

Health care professionals can make a big difference here. “Nurses are the most trusted health professionals,” said Dr. DeJarnett. Health care professionals can be effective communicators because of the personal anecdotes they bring with them. Because they work with local community members every day, they see the impacts of air quality, flooding, and extreme weather first hand.

Dr. DeJarnett recommended emphasizing resilience and staying positive when discussing these topics. There are many important statistics about the links between climate change and health, but those numbers can be overwhelming, negative, and off-putting. Dr. DeJarnett proposed that, instead, “We can frame things in terms of how taking action on climate change builds more resilient communities and stronger communities.”

To hear more from former Dr. Natasha DeJarnett, including some Q&A with CCL volunteers, watch the entire December meeting on YouTube or listen to the podcast. Follow Dr. DeJarnett on Twitter at @DrDeJarnett.

Sara Wanous has been the Membership Coordinator at Citizens’ Climate Lobby since January 2018. She has a B.A. in Economics and B.S. in Environmental Science and Policy from Chapman University and is pursuing a masters in Climate Science and Policy at the Scripps Institution of Oceanography.